F: drivers/char/digi*
DIRECTORY NOTIFICATION (DNOTIFY)
-P: Stephen Rothwell
-M: sfr@canb.auug.org.au
+P: Eric Paris
+M: eparis@parisplace.org
L: linux-kernel@vger.kernel.org
-S: Supported
+S: Maintained
F: Documentation/filesystems/dnotify.txt
F: fs/notify/dnotify/
F: include/linux/dnotify.h
M: john@johnmccutchan.com
P: Robert Love
M: rlove@rlove.org
+P: Eric Paris
+M: eparis@parisplace.org
L: linux-kernel@vger.kernel.org
S: Maintained
F: Documentation/filesystems/inotify.txt
#include <linux/cdev.h>
#include <linux/bootmem.h>
#include <linux/inotify.h>
+#include <linux/fsnotify.h>
#include <linux/mount.h>
#include <linux/async.h>
inode->i_private = NULL;
inode->i_mapping = mapping;
+#ifdef CONFIG_FSNOTIFY
+ inode->i_fsnotify_mask = 0;
+#endif
+
return inode;
out_free_security:
BUG_ON(inode_has_buffers(inode));
ima_inode_free(inode);
security_inode_free(inode);
+ fsnotify_inode_delete(inode);
if (inode->i_sb->s_op->destroy_inode)
inode->i_sb->s_op->destroy_inode(inode);
else
INIT_LIST_HEAD(&inode->inotify_watches);
mutex_init(&inode->inotify_mutex);
#endif
+#ifdef CONFIG_FSNOTIFY
+ INIT_HLIST_HEAD(&inode->i_fsnotify_mark_entries);
+#endif
}
EXPORT_SYMBOL(inode_init_once);
mutex_lock(&iprune_mutex);
spin_lock(&inode_lock);
inotify_unmount_inodes(&sb->s_inodes);
+ fsnotify_unmount_inodes(&sb->s_inodes);
busy = invalidate_list(&sb->s_inodes, &throw_away);
spin_unlock(&inode_lock);
+config FSNOTIFY
+ bool "Filesystem notification backend"
+ default y
+ ---help---
+ fsnotify is a backend for filesystem notification. fsnotify does
+ not provide any userspace interface but does provide the basis
+ needed for other notification schemes such as dnotify, inotify,
+ and fanotify.
+
+ Say Y here to enable fsnotify suport.
+
+ If unsure, say Y.
+
source "fs/notify/dnotify/Kconfig"
source "fs/notify/inotify/Kconfig"
+obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o
+
obj-y += dnotify/
obj-y += inotify/
config DNOTIFY
bool "Dnotify support"
+ depends on FSNOTIFY
default y
help
Dnotify is a directory-based per-fd file change notification system
*
* Copyright (C) 2000,2001,2002 Stephen Rothwell
*
+ * Copyright (C) 2009 Eric Paris <Red Hat Inc>
+ * dnotify was largly rewritten to use the new fsnotify infrastructure
+ *
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/fdtable.h>
+#include <linux/fsnotify_backend.h>
int dir_notify_enable __read_mostly = 1;
-static struct kmem_cache *dn_cache __read_mostly;
+static struct kmem_cache *dnotify_struct_cache __read_mostly;
+static struct kmem_cache *dnotify_mark_entry_cache __read_mostly;
+static struct fsnotify_group *dnotify_group __read_mostly;
+static DEFINE_MUTEX(dnotify_mark_mutex);
+
+/*
+ * dnotify will attach one of these to each inode (i_fsnotify_mark_entries) which
+ * is being watched by dnotify. If multiple userspace applications are watching
+ * the same directory with dnotify their information is chained in dn
+ */
+struct dnotify_mark_entry {
+ struct fsnotify_mark_entry fsn_entry;
+ struct dnotify_struct *dn;
+};
-static void redo_inode_mask(struct inode *inode)
+/*
+ * When a process starts or stops watching an inode the set of events which
+ * dnotify cares about for that inode may change. This function runs the
+ * list of everything receiving dnotify events about this directory and calculates
+ * the set of all those events. After it updates what dnotify is interested in
+ * it calls the fsnotify function so it can update the set of all events relevant
+ * to this inode.
+ */
+static void dnotify_recalc_inode_mask(struct fsnotify_mark_entry *entry)
{
- unsigned long new_mask;
+ __u32 new_mask, old_mask;
struct dnotify_struct *dn;
+ struct dnotify_mark_entry *dnentry = container_of(entry,
+ struct dnotify_mark_entry,
+ fsn_entry);
+
+ assert_spin_locked(&entry->lock);
+ old_mask = entry->mask;
new_mask = 0;
- for (dn = inode->i_dnotify; dn != NULL; dn = dn->dn_next)
- new_mask |= dn->dn_mask & ~DN_MULTISHOT;
- inode->i_dnotify_mask = new_mask;
+ for (dn = dnentry->dn; dn != NULL; dn = dn->dn_next)
+ new_mask |= (dn->dn_mask & ~FS_DN_MULTISHOT);
+ entry->mask = new_mask;
+
+ if (old_mask == new_mask)
+ return;
+
+ if (entry->inode)
+ fsnotify_recalc_inode_mask(entry->inode);
+}
+
+/*
+ * Mains fsnotify call where events are delivered to dnotify.
+ * Find the dnotify mark on the relevant inode, run the list of dnotify structs
+ * on that mark and determine which of them has expressed interest in receiving
+ * events of this type. When found send the correct process and signal and
+ * destroy the dnotify struct if it was not registered to receive multiple
+ * events.
+ */
+static int dnotify_handle_event(struct fsnotify_group *group,
+ struct fsnotify_event *event)
+{
+ struct fsnotify_mark_entry *entry = NULL;
+ struct dnotify_mark_entry *dnentry;
+ struct inode *to_tell;
+ struct dnotify_struct *dn;
+ struct dnotify_struct **prev;
+ struct fown_struct *fown;
+
+ to_tell = event->to_tell;
+
+ spin_lock(&to_tell->i_lock);
+ entry = fsnotify_find_mark_entry(group, to_tell);
+ spin_unlock(&to_tell->i_lock);
+
+ /* unlikely since we alreay passed dnotify_should_send_event() */
+ if (unlikely(!entry))
+ return 0;
+ dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry);
+
+ spin_lock(&entry->lock);
+ prev = &dnentry->dn;
+ while ((dn = *prev) != NULL) {
+ if ((dn->dn_mask & event->mask) == 0) {
+ prev = &dn->dn_next;
+ continue;
+ }
+ fown = &dn->dn_filp->f_owner;
+ send_sigio(fown, dn->dn_fd, POLL_MSG);
+ if (dn->dn_mask & FS_DN_MULTISHOT)
+ prev = &dn->dn_next;
+ else {
+ *prev = dn->dn_next;
+ kmem_cache_free(dnotify_struct_cache, dn);
+ dnotify_recalc_inode_mask(entry);
+ }
+ }
+
+ spin_unlock(&entry->lock);
+ fsnotify_put_mark(entry);
+
+ return 0;
+}
+
+/*
+ * Given an inode and mask determine if dnotify would be interested in sending
+ * userspace notification for that pair.
+ */
+static bool dnotify_should_send_event(struct fsnotify_group *group,
+ struct inode *inode, __u32 mask)
+{
+ struct fsnotify_mark_entry *entry;
+ bool send;
+
+ /* !dir_notify_enable should never get here, don't waste time checking
+ if (!dir_notify_enable)
+ return 0; */
+
+ /* not a dir, dnotify doesn't care */
+ if (!S_ISDIR(inode->i_mode))
+ return false;
+
+ spin_lock(&inode->i_lock);
+ entry = fsnotify_find_mark_entry(group, inode);
+ spin_unlock(&inode->i_lock);
+
+ /* no mark means no dnotify watch */
+ if (!entry)
+ return false;
+
+ mask = (mask & ~FS_EVENT_ON_CHILD);
+ send = (mask & entry->mask);
+
+ fsnotify_put_mark(entry); /* matches fsnotify_find_mark_entry */
+
+ return send;
+}
+
+static void dnotify_free_mark(struct fsnotify_mark_entry *entry)
+{
+ struct dnotify_mark_entry *dnentry = container_of(entry,
+ struct dnotify_mark_entry,
+ fsn_entry);
+
+ BUG_ON(dnentry->dn);
+
+ kmem_cache_free(dnotify_mark_entry_cache, dnentry);
}
+static struct fsnotify_ops dnotify_fsnotify_ops = {
+ .handle_event = dnotify_handle_event,
+ .should_send_event = dnotify_should_send_event,
+ .free_group_priv = NULL,
+ .freeing_mark = NULL,
+ .free_event_priv = NULL,
+};
+
+/*
+ * Called every time a file is closed. Looks first for a dnotify mark on the
+ * inode. If one is found run all of the ->dn entries attached to that
+ * mark for one relevant to this process closing the file and remove that
+ * dnotify_struct. If that was the last dnotify_struct also remove the
+ * fsnotify_mark_entry.
+ */
void dnotify_flush(struct file *filp, fl_owner_t id)
{
+ struct fsnotify_mark_entry *entry;
+ struct dnotify_mark_entry *dnentry;
struct dnotify_struct *dn;
struct dnotify_struct **prev;
struct inode *inode;
inode = filp->f_path.dentry->d_inode;
if (!S_ISDIR(inode->i_mode))
return;
+
spin_lock(&inode->i_lock);
- prev = &inode->i_dnotify;
+ entry = fsnotify_find_mark_entry(dnotify_group, inode);
+ spin_unlock(&inode->i_lock);
+ if (!entry)
+ return;
+ dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry);
+
+ mutex_lock(&dnotify_mark_mutex);
+
+ spin_lock(&entry->lock);
+ prev = &dnentry->dn;
while ((dn = *prev) != NULL) {
if ((dn->dn_owner == id) && (dn->dn_filp == filp)) {
*prev = dn->dn_next;
- redo_inode_mask(inode);
- kmem_cache_free(dn_cache, dn);
+ kmem_cache_free(dnotify_struct_cache, dn);
+ dnotify_recalc_inode_mask(entry);
break;
}
prev = &dn->dn_next;
}
- spin_unlock(&inode->i_lock);
+
+ spin_unlock(&entry->lock);
+
+ /* nothing else could have found us thanks to the dnotify_mark_mutex */
+ if (dnentry->dn == NULL)
+ fsnotify_destroy_mark_by_entry(entry);
+
+ fsnotify_recalc_group_mask(dnotify_group);
+
+ mutex_unlock(&dnotify_mark_mutex);
+
+ fsnotify_put_mark(entry);
+}
+
+/* this conversion is done only at watch creation */
+static __u32 convert_arg(unsigned long arg)
+{
+ __u32 new_mask = FS_EVENT_ON_CHILD;
+
+ if (arg & DN_MULTISHOT)
+ new_mask |= FS_DN_MULTISHOT;
+ if (arg & DN_DELETE)
+ new_mask |= (FS_DELETE | FS_MOVED_FROM);
+ if (arg & DN_MODIFY)
+ new_mask |= FS_MODIFY;
+ if (arg & DN_ACCESS)
+ new_mask |= FS_ACCESS;
+ if (arg & DN_ATTRIB)
+ new_mask |= FS_ATTRIB;
+ if (arg & DN_RENAME)
+ new_mask |= FS_DN_RENAME;
+ if (arg & DN_CREATE)
+ new_mask |= (FS_CREATE | FS_MOVED_TO);
+
+ return new_mask;
}
+/*
+ * If multiple processes watch the same inode with dnotify there is only one
+ * dnotify mark in inode->i_fsnotify_mark_entries but we chain a dnotify_struct
+ * onto that mark. This function either attaches the new dnotify_struct onto
+ * that list, or it |= the mask onto an existing dnofiy_struct.
+ */
+static int attach_dn(struct dnotify_struct *dn, struct dnotify_mark_entry *dnentry,
+ fl_owner_t id, int fd, struct file *filp, __u32 mask)
+{
+ struct dnotify_struct *odn;
+
+ odn = dnentry->dn;
+ while (odn != NULL) {
+ /* adding more events to existing dnofiy_struct? */
+ if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
+ odn->dn_fd = fd;
+ odn->dn_mask |= mask;
+ return -EEXIST;
+ }
+ odn = odn->dn_next;
+ }
+
+ dn->dn_mask = mask;
+ dn->dn_fd = fd;
+ dn->dn_filp = filp;
+ dn->dn_owner = id;
+ dn->dn_next = dnentry->dn;
+ dnentry->dn = dn;
+
+ return 0;
+}
+
+/*
+ * When a process calls fcntl to attach a dnotify watch to a directory it ends
+ * up here. Allocate both a mark for fsnotify to add and a dnotify_struct to be
+ * attached to the fsnotify_mark.
+ */
int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
{
+ struct dnotify_mark_entry *new_dnentry, *dnentry;
+ struct fsnotify_mark_entry *new_entry, *entry;
struct dnotify_struct *dn;
- struct dnotify_struct *odn;
- struct dnotify_struct **prev;
struct inode *inode;
fl_owner_t id = current->files;
struct file *f;
- int error = 0;
+ int destroy = 0, error = 0;
+ __u32 mask;
+
+ /* we use these to tell if we need to kfree */
+ new_entry = NULL;
+ dn = NULL;
+
+ if (!dir_notify_enable) {
+ error = -EINVAL;
+ goto out_err;
+ }
+ /* a 0 mask means we are explicitly removing the watch */
if ((arg & ~DN_MULTISHOT) == 0) {
dnotify_flush(filp, id);
- return 0;
+ error = 0;
+ goto out_err;
}
- if (!dir_notify_enable)
- return -EINVAL;
+
+ /* dnotify only works on directories */
inode = filp->f_path.dentry->d_inode;
- if (!S_ISDIR(inode->i_mode))
- return -ENOTDIR;
- dn = kmem_cache_alloc(dn_cache, GFP_KERNEL);
- if (dn == NULL)
- return -ENOMEM;
- spin_lock(&inode->i_lock);
- prev = &inode->i_dnotify;
- while ((odn = *prev) != NULL) {
- if ((odn->dn_owner == id) && (odn->dn_filp == filp)) {
- odn->dn_fd = fd;
- odn->dn_mask |= arg;
- inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
- goto out_free;
- }
- prev = &odn->dn_next;
+ if (!S_ISDIR(inode->i_mode)) {
+ error = -ENOTDIR;
+ goto out_err;
}
- rcu_read_lock();
- f = fcheck(fd);
- rcu_read_unlock();
- /* we'd lost the race with close(), sod off silently */
- /* note that inode->i_lock prevents reordering problems
- * between accesses to descriptor table and ->i_dnotify */
- if (f != filp)
- goto out_free;
+ /* expect most fcntl to add new rather than augment old */
+ dn = kmem_cache_alloc(dnotify_struct_cache, GFP_KERNEL);
+ if (!dn) {
+ error = -ENOMEM;
+ goto out_err;
+ }
- error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
- if (error)
- goto out_free;
+ /* new fsnotify mark, we expect most fcntl calls to add a new mark */
+ new_dnentry = kmem_cache_alloc(dnotify_mark_entry_cache, GFP_KERNEL);
+ if (!new_dnentry) {
+ error = -ENOMEM;
+ goto out_err;
+ }
- dn->dn_mask = arg;
- dn->dn_fd = fd;
- dn->dn_filp = filp;
- dn->dn_owner = id;
- inode->i_dnotify_mask |= arg & ~DN_MULTISHOT;
- dn->dn_next = inode->i_dnotify;
- inode->i_dnotify = dn;
- spin_unlock(&inode->i_lock);
- return 0;
+ /* convert the userspace DN_* "arg" to the internal FS_* defines in fsnotify */
+ mask = convert_arg(arg);
-out_free:
- spin_unlock(&inode->i_lock);
- kmem_cache_free(dn_cache, dn);
- return error;
-}
+ /* set up the new_entry and new_dnentry */
+ new_entry = &new_dnentry->fsn_entry;
+ fsnotify_init_mark(new_entry, dnotify_free_mark);
+ new_entry->mask = mask;
+ new_dnentry->dn = NULL;
-void __inode_dir_notify(struct inode *inode, unsigned long event)
-{
- struct dnotify_struct * dn;
- struct dnotify_struct **prev;
- struct fown_struct * fown;
- int changed = 0;
+ /* this is needed to prevent the fcntl/close race described below */
+ mutex_lock(&dnotify_mark_mutex);
+ /* add the new_entry or find an old one. */
spin_lock(&inode->i_lock);
- prev = &inode->i_dnotify;
- while ((dn = *prev) != NULL) {
- if ((dn->dn_mask & event) == 0) {
- prev = &dn->dn_next;
- continue;
- }
- fown = &dn->dn_filp->f_owner;
- send_sigio(fown, dn->dn_fd, POLL_MSG);
- if (dn->dn_mask & DN_MULTISHOT)
- prev = &dn->dn_next;
- else {
- *prev = dn->dn_next;
- changed = 1;
- kmem_cache_free(dn_cache, dn);
- }
- }
- if (changed)
- redo_inode_mask(inode);
+ entry = fsnotify_find_mark_entry(dnotify_group, inode);
spin_unlock(&inode->i_lock);
-}
-
-EXPORT_SYMBOL(__inode_dir_notify);
+ if (entry) {
+ dnentry = container_of(entry, struct dnotify_mark_entry, fsn_entry);
+ spin_lock(&entry->lock);
+ } else {
+ fsnotify_add_mark(new_entry, dnotify_group, inode);
+ spin_lock(&new_entry->lock);
+ entry = new_entry;
+ dnentry = new_dnentry;
+ /* we used new_entry, so don't free it */
+ new_entry = NULL;
+ }
-/*
- * This is hopelessly wrong, but unfixable without API changes. At
- * least it doesn't oops the kernel...
- *
- * To safely access ->d_parent we need to keep d_move away from it. Use the
- * dentry's d_lock for this.
- */
-void dnotify_parent(struct dentry *dentry, unsigned long event)
-{
- struct dentry *parent;
+ rcu_read_lock();
+ f = fcheck(fd);
+ rcu_read_unlock();
- if (!dir_notify_enable)
- return;
+ /* if (f != filp) means that we lost a race and another task/thread
+ * actually closed the fd we are still playing with before we grabbed
+ * the dnotify_mark_mutex and entry->lock. Since closing the fd is the
+ * only time we clean up the mark entries we need to get our mark off
+ * the list. */
+ if (f != filp) {
+ /* if we added ourselves, shoot ourselves, it's possible that
+ * the flush actually did shoot this entry. That's fine too
+ * since multiple calls to destroy_mark is perfectly safe, if
+ * we found a dnentry already attached to the inode, just sod
+ * off silently as the flush at close time dealt with it.
+ */
+ if (dnentry == new_dnentry)
+ destroy = 1;
+ goto out;
+ }
- spin_lock(&dentry->d_lock);
- parent = dentry->d_parent;
- if (parent->d_inode->i_dnotify_mask & event) {
- dget(parent);
- spin_unlock(&dentry->d_lock);
- __inode_dir_notify(parent->d_inode, event);
- dput(parent);
- } else {
- spin_unlock(&dentry->d_lock);
+ error = __f_setown(filp, task_pid(current), PIDTYPE_PID, 0);
+ if (error) {
+ /* if we added, we must shoot */
+ if (dnentry == new_dnentry)
+ destroy = 1;
+ goto out;
}
+
+ error = attach_dn(dn, dnentry, id, fd, filp, mask);
+ /* !error means that we attached the dn to the dnentry, so don't free it */
+ if (!error)
+ dn = NULL;
+ /* -EEXIST means that we didn't add this new dn and used an old one.
+ * that isn't an error (and the unused dn should be freed) */
+ else if (error == -EEXIST)
+ error = 0;
+
+ dnotify_recalc_inode_mask(entry);
+out:
+ spin_unlock(&entry->lock);
+
+ if (destroy)
+ fsnotify_destroy_mark_by_entry(entry);
+
+ fsnotify_recalc_group_mask(dnotify_group);
+
+ mutex_unlock(&dnotify_mark_mutex);
+ fsnotify_put_mark(entry);
+out_err:
+ if (new_entry)
+ fsnotify_put_mark(new_entry);
+ if (dn)
+ kmem_cache_free(dnotify_struct_cache, dn);
+ return error;
}
-EXPORT_SYMBOL_GPL(dnotify_parent);
static int __init dnotify_init(void)
{
- dn_cache = kmem_cache_create("dnotify_cache",
- sizeof(struct dnotify_struct), 0, SLAB_PANIC, NULL);
+ dnotify_struct_cache = KMEM_CACHE(dnotify_struct, SLAB_PANIC);
+ dnotify_mark_entry_cache = KMEM_CACHE(dnotify_mark_entry, SLAB_PANIC);
+
+ dnotify_group = fsnotify_obtain_group(DNOTIFY_GROUP_NUM,
+ 0, &dnotify_fsnotify_ops);
+ if (IS_ERR(dnotify_group))
+ panic("unable to allocate fsnotify group for dnotify\n");
return 0;
}
--- /dev/null
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/dcache.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/srcu.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+/*
+ * Clear all of the marks on an inode when it is being evicted from core
+ */
+void __fsnotify_inode_delete(struct inode *inode)
+{
+ fsnotify_clear_marks_by_inode(inode);
+}
+EXPORT_SYMBOL_GPL(__fsnotify_inode_delete);
+
+/*
+ * Given an inode, first check if we care what happens to our children. Inotify
+ * and dnotify both tell their parents about events. If we care about any event
+ * on a child we run all of our children and set a dentry flag saying that the
+ * parent cares. Thus when an event happens on a child it can quickly tell if
+ * if there is a need to find a parent and send the event to the parent.
+ */
+void __fsnotify_update_child_dentry_flags(struct inode *inode)
+{
+ struct dentry *alias;
+ int watched;
+
+ if (!S_ISDIR(inode->i_mode))
+ return;
+
+ /* determine if the children should tell inode about their events */
+ watched = fsnotify_inode_watches_children(inode);
+
+ spin_lock(&dcache_lock);
+ /* run all of the dentries associated with this inode. Since this is a
+ * directory, there damn well better only be one item on this list */
+ list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+ struct dentry *child;
+
+ /* run all of the children of the original inode and fix their
+ * d_flags to indicate parental interest (their parent is the
+ * original inode) */
+ list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) {
+ if (!child->d_inode)
+ continue;
+
+ spin_lock(&child->d_lock);
+ if (watched)
+ child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
+ else
+ child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
+ spin_unlock(&child->d_lock);
+ }
+ }
+ spin_unlock(&dcache_lock);
+}
+
+/* Notify this dentry's parent about a child's events. */
+void __fsnotify_parent(struct dentry *dentry, __u32 mask)
+{
+ struct dentry *parent;
+ struct inode *p_inode;
+ bool send = false;
+ bool should_update_children = false;
+
+ if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED))
+ return;
+
+ spin_lock(&dentry->d_lock);
+ parent = dentry->d_parent;
+ p_inode = parent->d_inode;
+
+ if (fsnotify_inode_watches_children(p_inode)) {
+ if (p_inode->i_fsnotify_mask & mask) {
+ dget(parent);
+ send = true;
+ }
+ } else {
+ /*
+ * The parent doesn't care about events on it's children but
+ * at least one child thought it did. We need to run all the
+ * children and update their d_flags to let them know p_inode
+ * doesn't care about them any more.
+ */
+ dget(parent);
+ should_update_children = true;
+ }
+
+ spin_unlock(&dentry->d_lock);
+
+ if (send) {
+ /* we are notifying a parent so come up with the new mask which
+ * specifies these are events which came from a child. */
+ mask |= FS_EVENT_ON_CHILD;
+
+ fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE,
+ dentry->d_name.name, 0);
+ dput(parent);
+ }
+
+ if (unlikely(should_update_children)) {
+ __fsnotify_update_child_dentry_flags(p_inode);
+ dput(parent);
+ }
+}
+EXPORT_SYMBOL_GPL(__fsnotify_parent);
+
+/*
+ * This is the main call to fsnotify. The VFS calls into hook specific functions
+ * in linux/fsnotify.h. Those functions then in turn call here. Here will call
+ * out to all of the registered fsnotify_group. Those groups can then use the
+ * notification event in whatever means they feel necessary.
+ */
+void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, const char *file_name, u32 cookie)
+{
+ struct fsnotify_group *group;
+ struct fsnotify_event *event = NULL;
+ int idx;
+ /* global tests shouldn't care about events on child only the specific event */
+ __u32 test_mask = (mask & ~FS_EVENT_ON_CHILD);
+
+ if (list_empty(&fsnotify_groups))
+ return;
+
+ if (!(test_mask & fsnotify_mask))
+ return;
+
+ if (!(test_mask & to_tell->i_fsnotify_mask))
+ return;
+ /*
+ * SRCU!! the groups list is very very much read only and the path is
+ * very hot. The VAST majority of events are not going to need to do
+ * anything other than walk the list so it's crazy to pre-allocate.
+ */
+ idx = srcu_read_lock(&fsnotify_grp_srcu);
+ list_for_each_entry_rcu(group, &fsnotify_groups, group_list) {
+ if (test_mask & group->mask) {
+ if (!group->ops->should_send_event(group, to_tell, mask))
+ continue;
+ if (!event) {
+ event = fsnotify_create_event(to_tell, mask, data, data_is, file_name, cookie);
+ /* shit, we OOM'd and now we can't tell, maybe
+ * someday someone else will want to do something
+ * here */
+ if (!event)
+ break;
+ }
+ group->ops->handle_event(group, event);
+ }
+ }
+ srcu_read_unlock(&fsnotify_grp_srcu, idx);
+ /*
+ * fsnotify_create_event() took a reference so the event can't be cleaned
+ * up while we are still trying to add it to lists, drop that one.
+ */
+ if (event)
+ fsnotify_put_event(event);
+}
+EXPORT_SYMBOL_GPL(fsnotify);
+
+static __init int fsnotify_init(void)
+{
+ return init_srcu_struct(&fsnotify_grp_srcu);
+}
+subsys_initcall(fsnotify_init);
--- /dev/null
+#ifndef __FS_NOTIFY_FSNOTIFY_H_
+#define __FS_NOTIFY_FSNOTIFY_H_
+
+#include <linux/list.h>
+#include <linux/fsnotify.h>
+#include <linux/srcu.h>
+#include <linux/types.h>
+
+/* protects reads of fsnotify_groups */
+extern struct srcu_struct fsnotify_grp_srcu;
+/* all groups which receive fsnotify events */
+extern struct list_head fsnotify_groups;
+/* all bitwise OR of all event types (FS_*) for all fsnotify_groups */
+extern __u32 fsnotify_mask;
+
+/* destroy all events sitting in this groups notification queue */
+extern void fsnotify_flush_notify(struct fsnotify_group *group);
+
+/* final kfree of a group */
+extern void fsnotify_final_destroy_group(struct fsnotify_group *group);
+
+/* run the list of all marks associated with inode and flag them to be freed */
+extern void fsnotify_clear_marks_by_inode(struct inode *inode);
+/*
+ * update the dentry->d_flags of all of inode's children to indicate if inode cares
+ * about events that happen to its children.
+ */
+extern void __fsnotify_update_child_dentry_flags(struct inode *inode);
+
+/* allocate and destroy and event holder to attach events to notification/access queues */
+extern struct fsnotify_event_holder *fsnotify_alloc_event_holder(void);
+extern void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder);
+
+#endif /* __FS_NOTIFY_FSNOTIFY_H_ */
--- /dev/null
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+#include <linux/rculist.h>
+#include <linux/wait.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+#include <asm/atomic.h>
+
+/* protects writes to fsnotify_groups and fsnotify_mask */
+static DEFINE_MUTEX(fsnotify_grp_mutex);
+/* protects reads while running the fsnotify_groups list */
+struct srcu_struct fsnotify_grp_srcu;
+/* all groups registered to receive filesystem notifications */
+LIST_HEAD(fsnotify_groups);
+/* bitwise OR of all events (FS_*) interesting to some group on this system */
+__u32 fsnotify_mask;
+
+/*
+ * When a new group registers or changes it's set of interesting events
+ * this function updates the fsnotify_mask to contain all interesting events
+ */
+void fsnotify_recalc_global_mask(void)
+{
+ struct fsnotify_group *group;
+ __u32 mask = 0;
+ int idx;
+
+ idx = srcu_read_lock(&fsnotify_grp_srcu);
+ list_for_each_entry_rcu(group, &fsnotify_groups, group_list)
+ mask |= group->mask;
+ srcu_read_unlock(&fsnotify_grp_srcu, idx);
+ fsnotify_mask = mask;
+}
+
+/*
+ * Update the group->mask by running all of the marks associated with this
+ * group and finding the bitwise | of all of the mark->mask. If we change
+ * the group->mask we need to update the global mask of events interesting
+ * to the system.
+ */
+void fsnotify_recalc_group_mask(struct fsnotify_group *group)
+{
+ __u32 mask = 0;
+ __u32 old_mask = group->mask;
+ struct fsnotify_mark_entry *entry;
+
+ spin_lock(&group->mark_lock);
+ list_for_each_entry(entry, &group->mark_entries, g_list)
+ mask |= entry->mask;
+ spin_unlock(&group->mark_lock);
+
+ group->mask = mask;
+
+ if (old_mask != mask)
+ fsnotify_recalc_global_mask();
+}
+
+/*
+ * Take a reference to a group so things found under the fsnotify_grp_mutex
+ * can't get freed under us
+ */
+static void fsnotify_get_group(struct fsnotify_group *group)
+{
+ atomic_inc(&group->refcnt);
+}
+
+/*
+ * Final freeing of a group
+ */
+void fsnotify_final_destroy_group(struct fsnotify_group *group)
+{
+ /* clear the notification queue of all events */
+ fsnotify_flush_notify(group);
+
+ if (group->ops->free_group_priv)
+ group->ops->free_group_priv(group);
+
+ kfree(group);
+}
+
+/*
+ * Trying to get rid of a group. We need to first get rid of any outstanding
+ * allocations and then free the group. Remember that fsnotify_clear_marks_by_group
+ * could miss marks that are being freed by inode and those marks could still
+ * hold a reference to this group (via group->num_marks) If we get into that
+ * situtation, the fsnotify_final_destroy_group will get called when that final
+ * mark is freed.
+ */
+static void fsnotify_destroy_group(struct fsnotify_group *group)
+{
+ /* clear all inode mark entries for this group */
+ fsnotify_clear_marks_by_group(group);
+
+ /* past the point of no return, matches the initial value of 1 */
+ if (atomic_dec_and_test(&group->num_marks))
+ fsnotify_final_destroy_group(group);
+}
+
+/*
+ * Remove this group from the global list of groups that will get events
+ * this can be done even if there are still references and things still using
+ * this group. This just stops the group from getting new events.
+ */
+static void __fsnotify_evict_group(struct fsnotify_group *group)
+{
+ BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
+
+ if (group->on_group_list)
+ list_del_rcu(&group->group_list);
+ group->on_group_list = 0;
+}
+
+/*
+ * Called when a group is no longer interested in getting events. This can be
+ * used if a group is misbehaving or if for some reason a group should no longer
+ * get any filesystem events.
+ */
+void fsnotify_evict_group(struct fsnotify_group *group)
+{
+ mutex_lock(&fsnotify_grp_mutex);
+ __fsnotify_evict_group(group);
+ mutex_unlock(&fsnotify_grp_mutex);
+}
+
+/*
+ * Drop a reference to a group. Free it if it's through.
+ */
+void fsnotify_put_group(struct fsnotify_group *group)
+{
+ if (!atomic_dec_and_mutex_lock(&group->refcnt, &fsnotify_grp_mutex))
+ return;
+
+ /*
+ * OK, now we know that there's no other users *and* we hold mutex,
+ * so no new references will appear
+ */
+ __fsnotify_evict_group(group);
+
+ /*
+ * now it's off the list, so the only thing we might care about is
+ * srcu access....
+ */
+ mutex_unlock(&fsnotify_grp_mutex);
+ synchronize_srcu(&fsnotify_grp_srcu);
+
+ /* and now it is really dead. _Nothing_ could be seeing it */
+ fsnotify_recalc_global_mask();
+ fsnotify_destroy_group(group);
+}
+
+/*
+ * Simply run the fsnotify_groups list and find a group which matches
+ * the given parameters. If a group is found we take a reference to that
+ * group.
+ */
+static struct fsnotify_group *fsnotify_find_group(unsigned int group_num, __u32 mask,
+ const struct fsnotify_ops *ops)
+{
+ struct fsnotify_group *group_iter;
+ struct fsnotify_group *group = NULL;
+
+ BUG_ON(!mutex_is_locked(&fsnotify_grp_mutex));
+
+ list_for_each_entry_rcu(group_iter, &fsnotify_groups, group_list) {
+ if (group_iter->group_num == group_num) {
+ if ((group_iter->mask == mask) &&
+ (group_iter->ops == ops)) {
+ fsnotify_get_group(group_iter);
+ group = group_iter;
+ } else
+ group = ERR_PTR(-EEXIST);
+ }
+ }
+ return group;
+}
+
+/*
+ * Either finds an existing group which matches the group_num, mask, and ops or
+ * creates a new group and adds it to the global group list. In either case we
+ * take a reference for the group returned.
+ */
+struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num, __u32 mask,
+ const struct fsnotify_ops *ops)
+{
+ struct fsnotify_group *group, *tgroup;
+
+ /* very low use, simpler locking if we just always alloc */
+ group = kmalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
+ if (!group)
+ return ERR_PTR(-ENOMEM);
+
+ atomic_set(&group->refcnt, 1);
+
+ group->on_group_list = 0;
+ group->group_num = group_num;
+ group->mask = mask;
+
+ mutex_init(&group->notification_mutex);
+ INIT_LIST_HEAD(&group->notification_list);
+ init_waitqueue_head(&group->notification_waitq);
+ group->q_len = 0;
+ group->max_events = UINT_MAX;
+
+ spin_lock_init(&group->mark_lock);
+ atomic_set(&group->num_marks, 0);
+ INIT_LIST_HEAD(&group->mark_entries);
+
+ group->ops = ops;
+
+ mutex_lock(&fsnotify_grp_mutex);
+ tgroup = fsnotify_find_group(group_num, mask, ops);
+ if (tgroup) {
+ /* group already exists */
+ mutex_unlock(&fsnotify_grp_mutex);
+ /* destroy the new one we made */
+ fsnotify_put_group(group);
+ return tgroup;
+ }
+
+ /* group not found, add a new one */
+ list_add_rcu(&group->group_list, &fsnotify_groups);
+ group->on_group_list = 1;
+ /* being on the fsnotify_groups list holds one num_marks */
+ atomic_inc(&group->num_marks);
+
+ mutex_unlock(&fsnotify_grp_mutex);
+
+ if (mask)
+ fsnotify_recalc_global_mask();
+
+ return group;
+}
--- /dev/null
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * fsnotify inode mark locking/lifetime/and refcnting
+ *
+ * REFCNT:
+ * The mark->refcnt tells how many "things" in the kernel currently are
+ * referencing this object. The object typically will live inside the kernel
+ * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task
+ * which can find this object holding the appropriete locks, can take a reference
+ * and the object itself is guarenteed to survive until the reference is dropped.
+ *
+ * LOCKING:
+ * There are 3 spinlocks involved with fsnotify inode marks and they MUST
+ * be taken in order as follows:
+ *
+ * entry->lock
+ * group->mark_lock
+ * inode->i_lock
+ *
+ * entry->lock protects 2 things, entry->group and entry->inode. You must hold
+ * that lock to dereference either of these things (they could be NULL even with
+ * the lock)
+ *
+ * group->mark_lock protects the mark_entries list anchored inside a given group
+ * and each entry is hooked via the g_list. It also sorta protects the
+ * free_g_list, which when used is anchored by a private list on the stack of the
+ * task which held the group->mark_lock.
+ *
+ * inode->i_lock protects the i_fsnotify_mark_entries list anchored inside a
+ * given inode and each entry is hooked via the i_list. (and sorta the
+ * free_i_list)
+ *
+ *
+ * LIFETIME:
+ * Inode marks survive between when they are added to an inode and when their
+ * refcnt==0.
+ *
+ * The inode mark can be cleared for a number of different reasons including:
+ * - The inode is unlinked for the last time. (fsnotify_inode_remove)
+ * - The inode is being evicted from cache. (fsnotify_inode_delete)
+ * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes)
+ * - Something explicitly requests that it be removed. (fsnotify_destroy_mark_by_entry)
+ * - The fsnotify_group associated with the mark is going away and all such marks
+ * need to be cleaned up. (fsnotify_clear_marks_by_group)
+ *
+ * Worst case we are given an inode and need to clean up all the marks on that
+ * inode. We take i_lock and walk the i_fsnotify_mark_entries safely. For each
+ * mark on the list we take a reference (so the mark can't disappear under us).
+ * We remove that mark form the inode's list of marks and we add this mark to a
+ * private list anchored on the stack using i_free_list; At this point we no
+ * longer fear anything finding the mark using the inode's list of marks.
+ *
+ * We can safely and locklessly run the private list on the stack of everything
+ * we just unattached from the original inode. For each mark on the private list
+ * we grab the mark-> and can thus dereference mark->group and mark->inode. If
+ * we see the group and inode are not NULL we take those locks. Now holding all
+ * 3 locks we can completely remove the mark from other tasks finding it in the
+ * future. Remember, 10 things might already be referencing this mark, but they
+ * better be holding a ref. We drop our reference we took before we unhooked it
+ * from the inode. When the ref hits 0 we can free the mark.
+ *
+ * Very similarly for freeing by group, except we use free_g_list.
+ *
+ * This has the very interesting property of being able to run concurrently with
+ * any (or all) other directions.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/writeback.h> /* for inode_lock */
+
+#include <asm/atomic.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+void fsnotify_get_mark(struct fsnotify_mark_entry *entry)
+{
+ atomic_inc(&entry->refcnt);
+}
+
+void fsnotify_put_mark(struct fsnotify_mark_entry *entry)
+{
+ if (atomic_dec_and_test(&entry->refcnt))
+ entry->free_mark(entry);
+}
+
+/*
+ * Recalculate the mask of events relevant to a given inode locked.
+ */
+static void fsnotify_recalc_inode_mask_locked(struct inode *inode)
+{
+ struct fsnotify_mark_entry *entry;
+ struct hlist_node *pos;
+ __u32 new_mask = 0;
+
+ assert_spin_locked(&inode->i_lock);
+
+ hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list)
+ new_mask |= entry->mask;
+ inode->i_fsnotify_mask = new_mask;
+}
+
+/*
+ * Recalculate the inode->i_fsnotify_mask, or the mask of all FS_* event types
+ * any notifier is interested in hearing for this inode.
+ */
+void fsnotify_recalc_inode_mask(struct inode *inode)
+{
+ spin_lock(&inode->i_lock);
+ fsnotify_recalc_inode_mask_locked(inode);
+ spin_unlock(&inode->i_lock);
+
+ __fsnotify_update_child_dentry_flags(inode);
+}
+
+/*
+ * Any time a mark is getting freed we end up here.
+ * The caller had better be holding a reference to this mark so we don't actually
+ * do the final put under the entry->lock
+ */
+void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry)
+{
+ struct fsnotify_group *group;
+ struct inode *inode;
+
+ spin_lock(&entry->lock);
+
+ group = entry->group;
+ inode = entry->inode;
+
+ BUG_ON(group && !inode);
+ BUG_ON(!group && inode);
+
+ /* if !group something else already marked this to die */
+ if (!group) {
+ spin_unlock(&entry->lock);
+ return;
+ }
+
+ /* 1 from caller and 1 for being on i_list/g_list */
+ BUG_ON(atomic_read(&entry->refcnt) < 2);
+
+ spin_lock(&group->mark_lock);
+ spin_lock(&inode->i_lock);
+
+ hlist_del_init(&entry->i_list);
+ entry->inode = NULL;
+
+ list_del_init(&entry->g_list);
+ entry->group = NULL;
+
+ fsnotify_put_mark(entry); /* for i_list and g_list */
+
+ /*
+ * this mark is now off the inode->i_fsnotify_mark_entries list and we
+ * hold the inode->i_lock, so this is the perfect time to update the
+ * inode->i_fsnotify_mask
+ */
+ fsnotify_recalc_inode_mask_locked(inode);
+
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&group->mark_lock);
+ spin_unlock(&entry->lock);
+
+ /*
+ * Some groups like to know that marks are being freed. This is a
+ * callback to the group function to let it know that this entry
+ * is being freed.
+ */
+ if (group->ops->freeing_mark)
+ group->ops->freeing_mark(entry, group);
+
+ /*
+ * __fsnotify_update_child_dentry_flags(inode);
+ *
+ * I really want to call that, but we can't, we have no idea if the inode
+ * still exists the second we drop the entry->lock.
+ *
+ * The next time an event arrive to this inode from one of it's children
+ * __fsnotify_parent will see that the inode doesn't care about it's
+ * children and will update all of these flags then. So really this
+ * is just a lazy update (and could be a perf win...)
+ */
+
+
+ iput(inode);
+
+ /*
+ * it's possible that this group tried to destroy itself, but this
+ * this mark was simultaneously being freed by inode. If that's the
+ * case, we finish freeing the group here.
+ */
+ if (unlikely(atomic_dec_and_test(&group->num_marks)))
+ fsnotify_final_destroy_group(group);
+}
+
+/*
+ * Given a group, destroy all of the marks associated with that group.
+ */
+void fsnotify_clear_marks_by_group(struct fsnotify_group *group)
+{
+ struct fsnotify_mark_entry *lentry, *entry;
+ LIST_HEAD(free_list);
+
+ spin_lock(&group->mark_lock);
+ list_for_each_entry_safe(entry, lentry, &group->mark_entries, g_list) {
+ list_add(&entry->free_g_list, &free_list);
+ list_del_init(&entry->g_list);
+ fsnotify_get_mark(entry);
+ }
+ spin_unlock(&group->mark_lock);
+
+ list_for_each_entry_safe(entry, lentry, &free_list, free_g_list) {
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
+ }
+}
+
+/*
+ * Given an inode, destroy all of the marks associated with that inode.
+ */
+void fsnotify_clear_marks_by_inode(struct inode *inode)
+{
+ struct fsnotify_mark_entry *entry, *lentry;
+ struct hlist_node *pos, *n;
+ LIST_HEAD(free_list);
+
+ spin_lock(&inode->i_lock);
+ hlist_for_each_entry_safe(entry, pos, n, &inode->i_fsnotify_mark_entries, i_list) {
+ list_add(&entry->free_i_list, &free_list);
+ hlist_del_init(&entry->i_list);
+ fsnotify_get_mark(entry);
+ }
+ spin_unlock(&inode->i_lock);
+
+ list_for_each_entry_safe(entry, lentry, &free_list, free_i_list) {
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
+ }
+}
+
+/*
+ * given a group and inode, find the mark associated with that combination.
+ * if found take a reference to that mark and return it, else return NULL
+ */
+struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group,
+ struct inode *inode)
+{
+ struct fsnotify_mark_entry *entry;
+ struct hlist_node *pos;
+
+ assert_spin_locked(&inode->i_lock);
+
+ hlist_for_each_entry(entry, pos, &inode->i_fsnotify_mark_entries, i_list) {
+ if (entry->group == group) {
+ fsnotify_get_mark(entry);
+ return entry;
+ }
+ }
+ return NULL;
+}
+
+/*
+ * Nothing fancy, just initialize lists and locks and counters.
+ */
+void fsnotify_init_mark(struct fsnotify_mark_entry *entry,
+ void (*free_mark)(struct fsnotify_mark_entry *entry))
+
+{
+ spin_lock_init(&entry->lock);
+ atomic_set(&entry->refcnt, 1);
+ INIT_HLIST_NODE(&entry->i_list);
+ entry->group = NULL;
+ entry->mask = 0;
+ entry->inode = NULL;
+ entry->free_mark = free_mark;
+}
+
+/*
+ * Attach an initialized mark entry to a given group and inode.
+ * These marks may be used for the fsnotify backend to determine which
+ * event types should be delivered to which group and for which inodes.
+ */
+int fsnotify_add_mark(struct fsnotify_mark_entry *entry,
+ struct fsnotify_group *group, struct inode *inode)
+{
+ struct fsnotify_mark_entry *lentry;
+ int ret = 0;
+
+ inode = igrab(inode);
+ if (unlikely(!inode))
+ return -EINVAL;
+
+ /*
+ * LOCKING ORDER!!!!
+ * entry->lock
+ * group->mark_lock
+ * inode->i_lock
+ */
+ spin_lock(&entry->lock);
+ spin_lock(&group->mark_lock);
+ spin_lock(&inode->i_lock);
+
+ entry->group = group;
+ entry->inode = inode;
+
+ lentry = fsnotify_find_mark_entry(group, inode);
+ if (!lentry) {
+ hlist_add_head(&entry->i_list, &inode->i_fsnotify_mark_entries);
+ list_add(&entry->g_list, &group->mark_entries);
+
+ fsnotify_get_mark(entry); /* for i_list and g_list */
+
+ atomic_inc(&group->num_marks);
+
+ fsnotify_recalc_inode_mask_locked(inode);
+ }
+
+ spin_unlock(&inode->i_lock);
+ spin_unlock(&group->mark_lock);
+ spin_unlock(&entry->lock);
+
+ if (lentry) {
+ ret = -EEXIST;
+ iput(inode);
+ fsnotify_put_mark(lentry);
+ } else {
+ __fsnotify_update_child_dentry_flags(inode);
+ }
+
+ return ret;
+}
+
+/**
+ * fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
+ * @list: list of inodes being unmounted (sb->s_inodes)
+ *
+ * Called with inode_lock held, protecting the unmounting super block's list
+ * of inodes, and with iprune_mutex held, keeping shrink_icache_memory() at bay.
+ * We temporarily drop inode_lock, however, and CAN block.
+ */
+void fsnotify_unmount_inodes(struct list_head *list)
+{
+ struct inode *inode, *next_i, *need_iput = NULL;
+
+ list_for_each_entry_safe(inode, next_i, list, i_sb_list) {
+ struct inode *need_iput_tmp;
+
+ /*
+ * We cannot __iget() an inode in state I_CLEAR, I_FREEING,
+ * I_WILL_FREE, or I_NEW which is fine because by that point
+ * the inode cannot have any associated watches.
+ */
+ if (inode->i_state & (I_CLEAR|I_FREEING|I_WILL_FREE|I_NEW))
+ continue;
+
+ /*
+ * If i_count is zero, the inode cannot have any watches and
+ * doing an __iget/iput with MS_ACTIVE clear would actually
+ * evict all inodes with zero i_count from icache which is
+ * unnecessarily violent and may in fact be illegal to do.
+ */
+ if (!atomic_read(&inode->i_count))
+ continue;
+
+ need_iput_tmp = need_iput;
+ need_iput = NULL;
+
+ /* In case fsnotify_inode_delete() drops a reference. */
+ if (inode != need_iput_tmp)
+ __iget(inode);
+ else
+ need_iput_tmp = NULL;
+
+ /* In case the dropping of a reference would nuke next_i. */
+ if ((&next_i->i_sb_list != list) &&
+ atomic_read(&next_i->i_count) &&
+ !(next_i->i_state & (I_CLEAR | I_FREEING | I_WILL_FREE))) {
+ __iget(next_i);
+ need_iput = next_i;
+ }
+
+ /*
+ * We can safely drop inode_lock here because we hold
+ * references on both inode and next_i. Also no new inodes
+ * will be added since the umount has begun. Finally,
+ * iprune_mutex keeps shrink_icache_memory() away.
+ */
+ spin_unlock(&inode_lock);
+
+ if (need_iput_tmp)
+ iput(need_iput_tmp);
+
+ /* for each watch, send FS_UNMOUNT and then remove it */
+ fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+
+ fsnotify_inode_delete(inode);
+
+ iput(inode);
+
+ spin_lock(&inode_lock);
+ }
+}
config INOTIFY
bool "Inotify file change notification support"
- default y
+ default n
---help---
- Say Y here to enable inotify support. Inotify is a file change
- notification system and a replacement for dnotify. Inotify fixes
- numerous shortcomings in dnotify and introduces several new features
- including multiple file events, one-shot support, and unmount
- notification.
+ Say Y here to enable legacy in kernel inotify support. Inotify is a
+ file change notification system. It is a replacement for dnotify.
+ This option only provides the legacy inotify in kernel API. There
+ are no in tree kernel users of this interface since it is deprecated.
+ You only need this if you are loading an out of tree kernel module
+ that uses inotify.
For more information, see <file:Documentation/filesystems/inotify.txt>
- If unsure, say Y.
+ If unsure, say N.
config INOTIFY_USER
bool "Inotify support for userspace"
- depends on INOTIFY
+ depends on FSNOTIFY
default y
---help---
Say Y here to enable inotify support for userspace, including the
associated system calls. Inotify allows monitoring of both files and
directories via a single open fd. Events are read from the file
descriptor, which is also select()- and poll()-able.
+ Inotify fixes numerous shortcomings in dnotify and introduces several
+ new features including multiple file events, one-shot support, and
+ unmount notification.
For more information, see <file:Documentation/filesystems/inotify.txt>
obj-$(CONFIG_INOTIFY) += inotify.o
-obj-$(CONFIG_INOTIFY_USER) += inotify_user.o
+obj-$(CONFIG_INOTIFY_USER) += inotify_fsnotify.o inotify_user.o
#include <linux/list.h>
#include <linux/writeback.h>
#include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
static atomic_t inotify_cookie;
*/
static int __init inotify_setup(void)
{
+ BUILD_BUG_ON(IN_ACCESS != FS_ACCESS);
+ BUILD_BUG_ON(IN_MODIFY != FS_MODIFY);
+ BUILD_BUG_ON(IN_ATTRIB != FS_ATTRIB);
+ BUILD_BUG_ON(IN_CLOSE_WRITE != FS_CLOSE_WRITE);
+ BUILD_BUG_ON(IN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
+ BUILD_BUG_ON(IN_OPEN != FS_OPEN);
+ BUILD_BUG_ON(IN_MOVED_FROM != FS_MOVED_FROM);
+ BUILD_BUG_ON(IN_MOVED_TO != FS_MOVED_TO);
+ BUILD_BUG_ON(IN_CREATE != FS_CREATE);
+ BUILD_BUG_ON(IN_DELETE != FS_DELETE);
+ BUILD_BUG_ON(IN_DELETE_SELF != FS_DELETE_SELF);
+ BUILD_BUG_ON(IN_MOVE_SELF != FS_MOVE_SELF);
+ BUILD_BUG_ON(IN_Q_OVERFLOW != FS_Q_OVERFLOW);
+
+ BUILD_BUG_ON(IN_UNMOUNT != FS_UNMOUNT);
+ BUILD_BUG_ON(IN_ISDIR != FS_IN_ISDIR);
+ BUILD_BUG_ON(IN_IGNORED != FS_IN_IGNORED);
+ BUILD_BUG_ON(IN_ONESHOT != FS_IN_ONESHOT);
+
atomic_set(&inotify_cookie, 0);
return 0;
--- /dev/null
+#include <linux/fsnotify_backend.h>
+#include <linux/inotify.h>
+#include <linux/slab.h> /* struct kmem_cache */
+
+extern struct kmem_cache *event_priv_cachep;
+
+struct inotify_event_private_data {
+ struct fsnotify_event_private_data fsnotify_event_priv_data;
+ int wd;
+};
+
+struct inotify_inode_mark_entry {
+ /* fsnotify_mark_entry MUST be the first thing */
+ struct fsnotify_mark_entry fsn_entry;
+ int wd;
+};
+
+extern void inotify_destroy_mark_entry(struct fsnotify_mark_entry *entry, struct fsnotify_group *group);
+extern void inotify_free_event_priv(struct fsnotify_event_private_data *event_priv);
+
+extern const struct fsnotify_ops inotify_fsnotify_ops;
--- /dev/null
+/*
+ * fs/inotify_user.c - inotify support for userspace
+ *
+ * Authors:
+ * John McCutchan <ttb@tentacle.dhs.org>
+ * Robert Love <rml@novell.com>
+ *
+ * Copyright (C) 2005 John McCutchan
+ * Copyright 2006 Hewlett-Packard Development Company, L.P.
+ *
+ * Copyright (C) 2009 Eric Paris <Red Hat Inc>
+ * inotify was largely rewriten to make use of the fsnotify infrastructure
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/fs.h> /* struct inode */
+#include <linux/fsnotify_backend.h>
+#include <linux/inotify.h>
+#include <linux/path.h> /* struct path */
+#include <linux/slab.h> /* kmem_* */
+#include <linux/types.h>
+
+#include "inotify.h"
+
+static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)
+{
+ struct fsnotify_mark_entry *entry;
+ struct inotify_inode_mark_entry *ientry;
+ struct inode *to_tell;
+ struct inotify_event_private_data *event_priv;
+ struct fsnotify_event_private_data *fsn_event_priv;
+ int wd, ret;
+
+ to_tell = event->to_tell;
+
+ spin_lock(&to_tell->i_lock);
+ entry = fsnotify_find_mark_entry(group, to_tell);
+ spin_unlock(&to_tell->i_lock);
+ /* race with watch removal? We already passes should_send */
+ if (unlikely(!entry))
+ return 0;
+ ientry = container_of(entry, struct inotify_inode_mark_entry,
+ fsn_entry);
+ wd = ientry->wd;
+
+ event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
+ if (unlikely(!event_priv))
+ return -ENOMEM;
+
+ fsn_event_priv = &event_priv->fsnotify_event_priv_data;
+
+ fsn_event_priv->group = group;
+ event_priv->wd = wd;
+
+ ret = fsnotify_add_notify_event(group, event, fsn_event_priv);
+ /* EEXIST is not an error */
+ if (ret == -EEXIST)
+ ret = 0;
+
+ /* did event_priv get attached? */
+ if (list_empty(&fsn_event_priv->event_list))
+ inotify_free_event_priv(fsn_event_priv);
+
+ /*
+ * If we hold the entry until after the event is on the queue
+ * IN_IGNORED won't be able to pass this event in the queue
+ */
+ fsnotify_put_mark(entry);
+
+ return ret;
+}
+
+static void inotify_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)
+{
+ inotify_destroy_mark_entry(entry, group);
+}
+
+static bool inotify_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask)
+{
+ struct fsnotify_mark_entry *entry;
+ bool send;
+
+ spin_lock(&inode->i_lock);
+ entry = fsnotify_find_mark_entry(group, inode);
+ spin_unlock(&inode->i_lock);
+ if (!entry)
+ return false;
+
+ mask = (mask & ~FS_EVENT_ON_CHILD);
+ send = (entry->mask & mask);
+
+ /* find took a reference */
+ fsnotify_put_mark(entry);
+
+ return send;
+}
+
+static int idr_callback(int id, void *p, void *data)
+{
+ BUG();
+ return 0;
+}
+
+static void inotify_free_group_priv(struct fsnotify_group *group)
+{
+ /* ideally the idr is empty and we won't hit the BUG in teh callback */
+ idr_for_each(&group->inotify_data.idr, idr_callback, NULL);
+ idr_remove_all(&group->inotify_data.idr);
+ idr_destroy(&group->inotify_data.idr);
+}
+
+void inotify_free_event_priv(struct fsnotify_event_private_data *fsn_event_priv)
+{
+ struct inotify_event_private_data *event_priv;
+
+
+ event_priv = container_of(fsn_event_priv, struct inotify_event_private_data,
+ fsnotify_event_priv_data);
+
+ kmem_cache_free(event_priv_cachep, event_priv);
+}
+
+const struct fsnotify_ops inotify_fsnotify_ops = {
+ .handle_event = inotify_handle_event,
+ .should_send_event = inotify_should_send_event,
+ .free_group_priv = inotify_free_group_priv,
+ .free_event_priv = inotify_free_event_priv,
+ .freeing_mark = inotify_freeing_mark,
+};
* Copyright (C) 2005 John McCutchan
* Copyright 2006 Hewlett-Packard Development Company, L.P.
*
+ * Copyright (C) 2009 Eric Paris <Red Hat Inc>
+ * inotify was largely rewriten to make use of the fsnotify infrastructure
+ *
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* General Public License for more details.
*/
-#include <linux/kernel.h>
-#include <linux/sched.h>
-#include <linux/slab.h>
-#include <linux/fs.h>
#include <linux/file.h>
-#include <linux/mount.h>
-#include <linux/namei.h>
-#include <linux/poll.h>
-#include <linux/init.h>
-#include <linux/list.h>
+#include <linux/fs.h> /* struct inode */
+#include <linux/fsnotify_backend.h>
+#include <linux/idr.h>
+#include <linux/init.h> /* module_init */
#include <linux/inotify.h>
+#include <linux/kernel.h> /* roundup() */
+#include <linux/magic.h> /* superblock magic number */
+#include <linux/mount.h> /* mntget */
+#include <linux/namei.h> /* LOOKUP_FOLLOW */
+#include <linux/path.h> /* struct path */
+#include <linux/sched.h> /* struct user */
+#include <linux/slab.h> /* struct kmem_cache */
#include <linux/syscalls.h>
-#include <linux/magic.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/poll.h>
+#include <linux/wait.h>
-#include <asm/ioctls.h>
+#include "inotify.h"
-static struct kmem_cache *watch_cachep __read_mostly;
-static struct kmem_cache *event_cachep __read_mostly;
+#include <asm/ioctls.h>
static struct vfsmount *inotify_mnt __read_mostly;
+/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */
+static struct inotify_event nul_inotify_event;
+
/* these are configurable via /proc/sys/fs/inotify/ */
static int inotify_max_user_instances __read_mostly;
-static int inotify_max_user_watches __read_mostly;
static int inotify_max_queued_events __read_mostly;
+int inotify_max_user_watches __read_mostly;
-/*
- * Lock ordering:
- *
- * inotify_dev->up_mutex (ensures we don't re-add the same watch)
- * inode->inotify_mutex (protects inode's watch list)
- * inotify_handle->mutex (protects inotify_handle's watch list)
- * inotify_dev->ev_mutex (protects device's event queue)
- */
+static struct kmem_cache *inotify_inode_mark_cachep __read_mostly;
+struct kmem_cache *event_priv_cachep __read_mostly;
+static struct fsnotify_event *inotify_ignored_event;
/*
- * Lifetimes of the main data structures:
- *
- * inotify_device: Lifetime is managed by reference count, from
- * sys_inotify_init() until release. Additional references can bump the count
- * via get_inotify_dev() and drop the count via put_inotify_dev().
- *
- * inotify_user_watch: Lifetime is from create_watch() to the receipt of an
- * IN_IGNORED event from inotify, or when using IN_ONESHOT, to receipt of the
- * first event, or to inotify_destroy().
+ * When inotify registers a new group it increments this and uses that
+ * value as an offset to set the fsnotify group "name" and priority.
*/
-
-/*
- * struct inotify_device - represents an inotify instance
- *
- * This structure is protected by the mutex 'mutex'.
- */
-struct inotify_device {
- wait_queue_head_t wq; /* wait queue for i/o */
- struct mutex ev_mutex; /* protects event queue */
- struct mutex up_mutex; /* synchronizes watch updates */
- struct list_head events; /* list of queued events */
- struct user_struct *user; /* user who opened this dev */
- struct inotify_handle *ih; /* inotify handle */
- struct fasync_struct *fa; /* async notification */
- atomic_t count; /* reference count */
- unsigned int queue_size; /* size of the queue (bytes) */
- unsigned int event_count; /* number of pending events */
- unsigned int max_events; /* maximum number of events */
-};
-
-/*
- * struct inotify_kernel_event - An inotify event, originating from a watch and
- * queued for user-space. A list of these is attached to each instance of the
- * device. In read(), this list is walked and all events that can fit in the
- * buffer are returned.
- *
- * Protected by dev->ev_mutex of the device in which we are queued.
- */
-struct inotify_kernel_event {
- struct inotify_event event; /* the user-space event */
- struct list_head list; /* entry in inotify_device's list */
- char *name; /* filename, if any */
-};
-
-/*
- * struct inotify_user_watch - our version of an inotify_watch, we add
- * a reference to the associated inotify_device.
- */
-struct inotify_user_watch {
- struct inotify_device *dev; /* associated device */
- struct inotify_watch wdata; /* inotify watch data */
-};
+static atomic_t inotify_grp_num;
#ifdef CONFIG_SYSCTL
};
#endif /* CONFIG_SYSCTL */
-static inline void get_inotify_dev(struct inotify_device *dev)
-{
- atomic_inc(&dev->count);
-}
-
-static inline void put_inotify_dev(struct inotify_device *dev)
-{
- if (atomic_dec_and_test(&dev->count)) {
- atomic_dec(&dev->user->inotify_devs);
- free_uid(dev->user);
- kfree(dev);
- }
-}
-
-/*
- * free_inotify_user_watch - cleans up the watch and its references
- */
-static void free_inotify_user_watch(struct inotify_watch *w)
-{
- struct inotify_user_watch *watch;
- struct inotify_device *dev;
-
- watch = container_of(w, struct inotify_user_watch, wdata);
- dev = watch->dev;
-
- atomic_dec(&dev->user->inotify_watches);
- put_inotify_dev(dev);
- kmem_cache_free(watch_cachep, watch);
-}
-
-/*
- * kernel_event - create a new kernel event with the given parameters
- *
- * This function can sleep.
- */
-static struct inotify_kernel_event * kernel_event(s32 wd, u32 mask, u32 cookie,
- const char *name)
-{
- struct inotify_kernel_event *kevent;
-
- kevent = kmem_cache_alloc(event_cachep, GFP_NOFS);
- if (unlikely(!kevent))
- return NULL;
-
- /* we hand this out to user-space, so zero it just in case */
- memset(&kevent->event, 0, sizeof(struct inotify_event));
-
- kevent->event.wd = wd;
- kevent->event.mask = mask;
- kevent->event.cookie = cookie;
-
- INIT_LIST_HEAD(&kevent->list);
-
- if (name) {
- size_t len, rem, event_size = sizeof(struct inotify_event);
-
- /*
- * We need to pad the filename so as to properly align an
- * array of inotify_event structures. Because the structure is
- * small and the common case is a small filename, we just round
- * up to the next multiple of the structure's sizeof. This is
- * simple and safe for all architectures.
- */
- len = strlen(name) + 1;
- rem = event_size - len;
- if (len > event_size) {
- rem = event_size - (len % event_size);
- if (len % event_size == 0)
- rem = 0;
- }
-
- kevent->name = kmalloc(len + rem, GFP_NOFS);
- if (unlikely(!kevent->name)) {
- kmem_cache_free(event_cachep, kevent);
- return NULL;
- }
- memcpy(kevent->name, name, len);
- if (rem)
- memset(kevent->name + len, 0, rem);
- kevent->event.len = len + rem;
- } else {
- kevent->event.len = 0;
- kevent->name = NULL;
- }
-
- return kevent;
-}
-
-/*
- * inotify_dev_get_event - return the next event in the given dev's queue
- *
- * Caller must hold dev->ev_mutex.
- */
-static inline struct inotify_kernel_event *
-inotify_dev_get_event(struct inotify_device *dev)
-{
- return list_entry(dev->events.next, struct inotify_kernel_event, list);
-}
-
-/*
- * inotify_dev_get_last_event - return the last event in the given dev's queue
- *
- * Caller must hold dev->ev_mutex.
- */
-static inline struct inotify_kernel_event *
-inotify_dev_get_last_event(struct inotify_device *dev)
+static inline __u32 inotify_arg_to_mask(u32 arg)
{
- if (list_empty(&dev->events))
- return NULL;
- return list_entry(dev->events.prev, struct inotify_kernel_event, list);
-}
+ __u32 mask;
-/*
- * inotify_dev_queue_event - event handler registered with core inotify, adds
- * a new event to the given device
- *
- * Can sleep (calls kernel_event()).
- */
-static void inotify_dev_queue_event(struct inotify_watch *w, u32 wd, u32 mask,
- u32 cookie, const char *name,
- struct inode *ignored)
-{
- struct inotify_user_watch *watch;
- struct inotify_device *dev;
- struct inotify_kernel_event *kevent, *last;
+ /* everything should accept their own ignored and cares about children */
+ mask = (FS_IN_IGNORED | FS_EVENT_ON_CHILD);
- watch = container_of(w, struct inotify_user_watch, wdata);
- dev = watch->dev;
+ /* mask off the flags used to open the fd */
+ mask |= (arg & (IN_ALL_EVENTS | IN_ONESHOT));
- mutex_lock(&dev->ev_mutex);
-
- /* we can safely put the watch as we don't reference it while
- * generating the event
- */
- if (mask & IN_IGNORED || w->mask & IN_ONESHOT)
- put_inotify_watch(w); /* final put */
-
- /* coalescing: drop this event if it is a dupe of the previous */
- last = inotify_dev_get_last_event(dev);
- if (last && last->event.mask == mask && last->event.wd == wd &&
- last->event.cookie == cookie) {
- const char *lastname = last->name;
-
- if (!name && !lastname)
- goto out;
- if (name && lastname && !strcmp(lastname, name))
- goto out;
- }
-
- /* the queue overflowed and we already sent the Q_OVERFLOW event */
- if (unlikely(dev->event_count > dev->max_events))
- goto out;
-
- /* if the queue overflows, we need to notify user space */
- if (unlikely(dev->event_count == dev->max_events))
- kevent = kernel_event(-1, IN_Q_OVERFLOW, cookie, NULL);
- else
- kevent = kernel_event(wd, mask, cookie, name);
-
- if (unlikely(!kevent))
- goto out;
-
- /* queue the event and wake up anyone waiting */
- dev->event_count++;
- dev->queue_size += sizeof(struct inotify_event) + kevent->event.len;
- list_add_tail(&kevent->list, &dev->events);
- wake_up_interruptible(&dev->wq);
- kill_fasync(&dev->fa, SIGIO, POLL_IN);
-
-out:
- mutex_unlock(&dev->ev_mutex);
-}
-
-/*
- * remove_kevent - cleans up the given kevent
- *
- * Caller must hold dev->ev_mutex.
- */
-static void remove_kevent(struct inotify_device *dev,
- struct inotify_kernel_event *kevent)
-{
- list_del(&kevent->list);
-
- dev->event_count--;
- dev->queue_size -= sizeof(struct inotify_event) + kevent->event.len;
-}
-
-/*
- * free_kevent - frees the given kevent.
- */
-static void free_kevent(struct inotify_kernel_event *kevent)
-{
- kfree(kevent->name);
- kmem_cache_free(event_cachep, kevent);
-}
-
-/*
- * inotify_dev_event_dequeue - destroy an event on the given device
- *
- * Caller must hold dev->ev_mutex.
- */
-static void inotify_dev_event_dequeue(struct inotify_device *dev)
-{
- if (!list_empty(&dev->events)) {
- struct inotify_kernel_event *kevent;
- kevent = inotify_dev_get_event(dev);
- remove_kevent(dev, kevent);
- free_kevent(kevent);
- }
-}
-
-/*
- * find_inode - resolve a user-given path to a specific inode
- */
-static int find_inode(const char __user *dirname, struct path *path,
- unsigned flags)
-{
- int error;
-
- error = user_path_at(AT_FDCWD, dirname, flags, path);
- if (error)
- return error;
- /* you can only watch an inode if you have read permissions on it */
- error = inode_permission(path->dentry->d_inode, MAY_READ);
- if (error)
- path_put(path);
- return error;
+ return mask;
}
-/*
- * create_watch - creates a watch on the given device.
- *
- * Callers must hold dev->up_mutex.
- */
-static int create_watch(struct inotify_device *dev, struct inode *inode,
- u32 mask)
+static inline u32 inotify_mask_to_arg(__u32 mask)
{
- struct inotify_user_watch *watch;
- int ret;
-
- if (atomic_read(&dev->user->inotify_watches) >=
- inotify_max_user_watches)
- return -ENOSPC;
-
- watch = kmem_cache_alloc(watch_cachep, GFP_KERNEL);
- if (unlikely(!watch))
- return -ENOMEM;
-
- /* save a reference to device and bump the count to make it official */
- get_inotify_dev(dev);
- watch->dev = dev;
-
- atomic_inc(&dev->user->inotify_watches);
-
- inotify_init_watch(&watch->wdata);
- ret = inotify_add_watch(dev->ih, &watch->wdata, inode, mask);
- if (ret < 0)
- free_inotify_user_watch(&watch->wdata);
-
- return ret;
+ return mask & (IN_ALL_EVENTS | IN_ISDIR | IN_UNMOUNT | IN_IGNORED |
+ IN_Q_OVERFLOW);
}
-/* Device Interface */
-
+/* intofiy userspace file descriptor functions */
static unsigned int inotify_poll(struct file *file, poll_table *wait)
{
- struct inotify_device *dev = file->private_data;
+ struct fsnotify_group *group = file->private_data;
int ret = 0;
- poll_wait(file, &dev->wq, wait);
- mutex_lock(&dev->ev_mutex);
- if (!list_empty(&dev->events))
+ poll_wait(file, &group->notification_waitq, wait);
+ mutex_lock(&group->notification_mutex);
+ if (!fsnotify_notify_queue_is_empty(group))
ret = POLLIN | POLLRDNORM;
- mutex_unlock(&dev->ev_mutex);
+ mutex_unlock(&group->notification_mutex);
return ret;
}
* enough to fit in "count". Return an error pointer if
* not large enough.
*
- * Called with the device ev_mutex held.
+ * Called with the group->notification_mutex held.
*/
-static struct inotify_kernel_event *get_one_event(struct inotify_device *dev,
- size_t count)
+static struct fsnotify_event *get_one_event(struct fsnotify_group *group,
+ size_t count)
{
size_t event_size = sizeof(struct inotify_event);
- struct inotify_kernel_event *kevent;
+ struct fsnotify_event *event;
- if (list_empty(&dev->events))
+ if (fsnotify_notify_queue_is_empty(group))
return NULL;
- kevent = inotify_dev_get_event(dev);
- if (kevent->name)
- event_size += kevent->event.len;
+ event = fsnotify_peek_notify_event(group);
+
+ event_size += roundup(event->name_len, event_size);
if (event_size > count)
return ERR_PTR(-EINVAL);
- remove_kevent(dev, kevent);
- return kevent;
+ /* held the notification_mutex the whole time, so this is the
+ * same event we peeked above */
+ fsnotify_remove_notify_event(group);
+
+ return event;
}
/*
* We already checked that the event size is smaller than the
* buffer we had in "get_one_event()" above.
*/
-static ssize_t copy_event_to_user(struct inotify_kernel_event *kevent,
+static ssize_t copy_event_to_user(struct fsnotify_group *group,
+ struct fsnotify_event *event,
char __user *buf)
{
+ struct inotify_event inotify_event;
+ struct fsnotify_event_private_data *fsn_priv;
+ struct inotify_event_private_data *priv;
size_t event_size = sizeof(struct inotify_event);
+ size_t name_len;
+
+ /* we get the inotify watch descriptor from the event private data */
+ spin_lock(&event->lock);
+ fsn_priv = fsnotify_remove_priv_from_event(group, event);
+ spin_unlock(&event->lock);
+
+ if (!fsn_priv)
+ inotify_event.wd = -1;
+ else {
+ priv = container_of(fsn_priv, struct inotify_event_private_data,
+ fsnotify_event_priv_data);
+ inotify_event.wd = priv->wd;
+ inotify_free_event_priv(fsn_priv);
+ }
+
+ /* round up event->name_len so it is a multiple of event_size */
+ name_len = roundup(event->name_len, event_size);
+ inotify_event.len = name_len;
+
+ inotify_event.mask = inotify_mask_to_arg(event->mask);
+ inotify_event.cookie = event->sync_cookie;
- if (copy_to_user(buf, &kevent->event, event_size))
+ /* send the main event */
+ if (copy_to_user(buf, &inotify_event, event_size))
return -EFAULT;
- if (kevent->name) {
- buf += event_size;
+ buf += event_size;
- if (copy_to_user(buf, kevent->name, kevent->event.len))
+ /*
+ * fsnotify only stores the pathname, so here we have to send the pathname
+ * and then pad that pathname out to a multiple of sizeof(inotify_event)
+ * with zeros. I get my zeros from the nul_inotify_event.
+ */
+ if (name_len) {
+ unsigned int len_to_zero = name_len - event->name_len;
+ /* copy the path name */
+ if (copy_to_user(buf, event->file_name, event->name_len))
return -EFAULT;
+ buf += event->name_len;
- event_size += kevent->event.len;
+ /* fill userspace with 0's from nul_inotify_event */
+ if (copy_to_user(buf, &nul_inotify_event, len_to_zero))
+ return -EFAULT;
+ buf += len_to_zero;
+ event_size += name_len;
}
+
return event_size;
}
static ssize_t inotify_read(struct file *file, char __user *buf,
size_t count, loff_t *pos)
{
- struct inotify_device *dev;
+ struct fsnotify_group *group;
+ struct fsnotify_event *kevent;
char __user *start;
int ret;
DEFINE_WAIT(wait);
start = buf;
- dev = file->private_data;
+ group = file->private_data;
while (1) {
- struct inotify_kernel_event *kevent;
+ prepare_to_wait(&group->notification_waitq, &wait, TASK_INTERRUPTIBLE);
- prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE);
-
- mutex_lock(&dev->ev_mutex);
- kevent = get_one_event(dev, count);
- mutex_unlock(&dev->ev_mutex);
+ mutex_lock(&group->notification_mutex);
+ kevent = get_one_event(group, count);
+ mutex_unlock(&group->notification_mutex);
if (kevent) {
ret = PTR_ERR(kevent);
if (IS_ERR(kevent))
break;
- ret = copy_event_to_user(kevent, buf);
- free_kevent(kevent);
+ ret = copy_event_to_user(group, kevent, buf);
+ fsnotify_put_event(kevent);
if (ret < 0)
break;
buf += ret;
schedule();
}
- finish_wait(&dev->wq, &wait);
+ finish_wait(&group->notification_waitq, &wait);
if (start != buf && ret != -EFAULT)
ret = buf - start;
return ret;
static int inotify_fasync(int fd, struct file *file, int on)
{
- struct inotify_device *dev = file->private_data;
+ struct fsnotify_group *group = file->private_data;
- return fasync_helper(fd, file, on, &dev->fa) >= 0 ? 0 : -EIO;
+ return fasync_helper(fd, file, on, &group->inotify_data.fa) >= 0 ? 0 : -EIO;
}
static int inotify_release(struct inode *ignored, struct file *file)
{
- struct inotify_device *dev = file->private_data;
-
- inotify_destroy(dev->ih);
+ struct fsnotify_group *group = file->private_data;
- /* destroy all of the events on this device */
- mutex_lock(&dev->ev_mutex);
- while (!list_empty(&dev->events))
- inotify_dev_event_dequeue(dev);
- mutex_unlock(&dev->ev_mutex);
+ fsnotify_clear_marks_by_group(group);
- /* free this device: the put matching the get in inotify_init() */
- put_inotify_dev(dev);
+ /* free this group, matching get was inotify_init->fsnotify_obtain_group */
+ fsnotify_put_group(group);
return 0;
}
static long inotify_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
- struct inotify_device *dev;
+ struct fsnotify_group *group;
+ struct fsnotify_event_holder *holder;
+ struct fsnotify_event *event;
void __user *p;
int ret = -ENOTTY;
+ size_t send_len = 0;
- dev = file->private_data;
+ group = file->private_data;
p = (void __user *) arg;
switch (cmd) {
case FIONREAD:
- ret = put_user(dev->queue_size, (int __user *) p);
+ mutex_lock(&group->notification_mutex);
+ list_for_each_entry(holder, &group->notification_list, event_list) {
+ event = holder->event;
+ send_len += sizeof(struct inotify_event);
+ send_len += roundup(event->name_len,
+ sizeof(struct inotify_event));
+ }
+ mutex_unlock(&group->notification_mutex);
+ ret = put_user(send_len, (int __user *) p);
break;
}
}
static const struct file_operations inotify_fops = {
- .poll = inotify_poll,
- .read = inotify_read,
- .fasync = inotify_fasync,
- .release = inotify_release,
- .unlocked_ioctl = inotify_ioctl,
+ .poll = inotify_poll,
+ .read = inotify_read,
+ .fasync = inotify_fasync,
+ .release = inotify_release,
+ .unlocked_ioctl = inotify_ioctl,
.compat_ioctl = inotify_ioctl,
};
-static const struct inotify_operations inotify_user_ops = {
- .handle_event = inotify_dev_queue_event,
- .destroy_watch = free_inotify_user_watch,
-};
+/*
+ * find_inode - resolve a user-given path to a specific inode
+ */
+static int inotify_find_inode(const char __user *dirname, struct path *path, unsigned flags)
+{
+ int error;
+
+ error = user_path_at(AT_FDCWD, dirname, flags, path);
+ if (error)
+ return error;
+ /* you can only watch an inode if you have read permissions on it */
+ error = inode_permission(path->dentry->d_inode, MAY_READ);
+ if (error)
+ path_put(path);
+ return error;
+}
+
+/*
+ * When, for whatever reason, inotify is done with a mark (or what used to be a
+ * watch) we need to remove that watch from the idr and we need to send IN_IGNORED
+ * for the given wd.
+ *
+ * There is a bit of recursion here. The loop looks like:
+ * inotify_destroy_mark_entry -> fsnotify_destroy_mark_by_entry ->
+ * inotify_freeing_mark -> inotify_destory_mark_entry -> restart
+ * But the loop is broken in 2 places. fsnotify_destroy_mark_by_entry sets
+ * entry->group = NULL before the call to inotify_freeing_mark, so the if (egroup)
+ * test below will not call back to fsnotify again. But even if that test wasn't
+ * there this would still be safe since fsnotify_destroy_mark_by_entry() is
+ * safe from recursion.
+ */
+void inotify_destroy_mark_entry(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)
+{
+ struct inotify_inode_mark_entry *ientry;
+ struct inotify_event_private_data *event_priv;
+ struct fsnotify_event_private_data *fsn_event_priv;
+ struct fsnotify_group *egroup;
+ struct idr *idr;
+
+ spin_lock(&entry->lock);
+ egroup = entry->group;
+
+ /* if egroup we aren't really done and something might still send events
+ * for this inode, on the callback we'll send the IN_IGNORED */
+ if (egroup) {
+ spin_unlock(&entry->lock);
+ fsnotify_destroy_mark_by_entry(entry);
+ return;
+ }
+ spin_unlock(&entry->lock);
+
+ ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
+
+ event_priv = kmem_cache_alloc(event_priv_cachep, GFP_KERNEL);
+ if (unlikely(!event_priv))
+ goto skip_send_ignore;
+
+ fsn_event_priv = &event_priv->fsnotify_event_priv_data;
+
+ fsn_event_priv->group = group;
+ event_priv->wd = ientry->wd;
+
+ fsnotify_add_notify_event(group, inotify_ignored_event, fsn_event_priv);
+
+ /* did the private data get added? */
+ if (list_empty(&fsn_event_priv->event_list))
+ inotify_free_event_priv(fsn_event_priv);
+
+skip_send_ignore:
+
+ /* remove this entry from the idr */
+ spin_lock(&group->inotify_data.idr_lock);
+ idr = &group->inotify_data.idr;
+ idr_remove(idr, ientry->wd);
+ spin_unlock(&group->inotify_data.idr_lock);
+
+ /* removed from idr, drop that reference */
+ fsnotify_put_mark(entry);
+}
+
+/* ding dong the mark is dead */
+static void inotify_free_mark(struct fsnotify_mark_entry *entry)
+{
+ struct inotify_inode_mark_entry *ientry = (struct inotify_inode_mark_entry *)entry;
+
+ kmem_cache_free(inotify_inode_mark_cachep, ientry);
+}
+
+static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
+{
+ struct fsnotify_mark_entry *entry = NULL;
+ struct inotify_inode_mark_entry *ientry;
+ int ret = 0;
+ int add = (arg & IN_MASK_ADD);
+ __u32 mask;
+ __u32 old_mask, new_mask;
+
+ /* don't allow invalid bits: we don't want flags set */
+ mask = inotify_arg_to_mask(arg);
+ if (unlikely(!mask))
+ return -EINVAL;
+
+ ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
+ if (unlikely(!ientry))
+ return -ENOMEM;
+ /* we set the mask at the end after attaching it */
+ fsnotify_init_mark(&ientry->fsn_entry, inotify_free_mark);
+ ientry->wd = 0;
+
+find_entry:
+ spin_lock(&inode->i_lock);
+ entry = fsnotify_find_mark_entry(group, inode);
+ spin_unlock(&inode->i_lock);
+ if (entry) {
+ kmem_cache_free(inotify_inode_mark_cachep, ientry);
+ ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
+ } else {
+ if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) {
+ ret = -ENOSPC;
+ goto out_err;
+ }
+
+ ret = fsnotify_add_mark(&ientry->fsn_entry, group, inode);
+ if (ret == -EEXIST)
+ goto find_entry;
+ else if (ret)
+ goto out_err;
+
+ entry = &ientry->fsn_entry;
+retry:
+ ret = -ENOMEM;
+ if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
+ goto out_err;
+
+ spin_lock(&group->inotify_data.idr_lock);
+ /* if entry is added to the idr we keep the reference obtained
+ * through fsnotify_mark_add. remember to drop this reference
+ * when entry is removed from idr */
+ ret = idr_get_new_above(&group->inotify_data.idr, entry,
+ ++group->inotify_data.last_wd,
+ &ientry->wd);
+ spin_unlock(&group->inotify_data.idr_lock);
+ if (ret) {
+ if (ret == -EAGAIN)
+ goto retry;
+ goto out_err;
+ }
+ atomic_inc(&group->inotify_data.user->inotify_watches);
+ }
+
+ spin_lock(&entry->lock);
+
+ old_mask = entry->mask;
+ if (add) {
+ entry->mask |= mask;
+ new_mask = entry->mask;
+ } else {
+ entry->mask = mask;
+ new_mask = entry->mask;
+ }
+
+ spin_unlock(&entry->lock);
+
+ if (old_mask != new_mask) {
+ /* more bits in old than in new? */
+ int dropped = (old_mask & ~new_mask);
+ /* more bits in this entry than the inode's mask? */
+ int do_inode = (new_mask & ~inode->i_fsnotify_mask);
+ /* more bits in this entry than the group? */
+ int do_group = (new_mask & ~group->mask);
+
+ /* update the inode with this new entry */
+ if (dropped || do_inode)
+ fsnotify_recalc_inode_mask(inode);
+
+ /* update the group mask with the new mask */
+ if (dropped || do_group)
+ fsnotify_recalc_group_mask(group);
+ }
+
+ return ientry->wd;
+
+out_err:
+ /* see this isn't supposed to happen, just kill the watch */
+ if (entry) {
+ fsnotify_destroy_mark_by_entry(entry);
+ fsnotify_put_mark(entry);
+ }
+ return ret;
+}
+
+static struct fsnotify_group *inotify_new_group(struct user_struct *user, unsigned int max_events)
+{
+ struct fsnotify_group *group;
+ unsigned int grp_num;
+
+ /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */
+ grp_num = (INOTIFY_GROUP_NUM - atomic_inc_return(&inotify_grp_num));
+ group = fsnotify_obtain_group(grp_num, 0, &inotify_fsnotify_ops);
+ if (IS_ERR(group))
+ return group;
+
+ group->max_events = max_events;
+
+ spin_lock_init(&group->inotify_data.idr_lock);
+ idr_init(&group->inotify_data.idr);
+ group->inotify_data.last_wd = 0;
+ group->inotify_data.user = user;
+ group->inotify_data.fa = NULL;
+
+ return group;
+}
+
+
+/* inotify syscalls */
SYSCALL_DEFINE1(inotify_init1, int, flags)
{
- struct inotify_device *dev;
- struct inotify_handle *ih;
+ struct fsnotify_group *group;
struct user_struct *user;
struct file *filp;
int fd, ret;
goto out_free_uid;
}
- dev = kmalloc(sizeof(struct inotify_device), GFP_KERNEL);
- if (unlikely(!dev)) {
- ret = -ENOMEM;
+ /* fsnotify_obtain_group took a reference to group, we put this when we kill the file in the end */
+ group = inotify_new_group(user, inotify_max_queued_events);
+ if (IS_ERR(group)) {
+ ret = PTR_ERR(group);
goto out_free_uid;
}
- ih = inotify_init(&inotify_user_ops);
- if (IS_ERR(ih)) {
- ret = PTR_ERR(ih);
- goto out_free_dev;
- }
- dev->ih = ih;
- dev->fa = NULL;
-
filp->f_op = &inotify_fops;
filp->f_path.mnt = mntget(inotify_mnt);
filp->f_path.dentry = dget(inotify_mnt->mnt_root);
filp->f_mapping = filp->f_path.dentry->d_inode->i_mapping;
filp->f_mode = FMODE_READ;
filp->f_flags = O_RDONLY | (flags & O_NONBLOCK);
- filp->private_data = dev;
-
- INIT_LIST_HEAD(&dev->events);
- init_waitqueue_head(&dev->wq);
- mutex_init(&dev->ev_mutex);
- mutex_init(&dev->up_mutex);
- dev->event_count = 0;
- dev->queue_size = 0;
- dev->max_events = inotify_max_queued_events;
- dev->user = user;
- atomic_set(&dev->count, 0);
-
- get_inotify_dev(dev);
+ filp->private_data = group;
+
atomic_inc(&user->inotify_devs);
+
fd_install(fd, filp);
return fd;
-out_free_dev:
- kfree(dev);
+
out_free_uid:
free_uid(user);
put_filp(filp);
SYSCALL_DEFINE3(inotify_add_watch, int, fd, const char __user *, pathname,
u32, mask)
{
+ struct fsnotify_group *group;
struct inode *inode;
- struct inotify_device *dev;
struct path path;
struct file *filp;
int ret, fput_needed;
if (mask & IN_ONLYDIR)
flags |= LOOKUP_DIRECTORY;
- ret = find_inode(pathname, &path, flags);
- if (unlikely(ret))
+ ret = inotify_find_inode(pathname, &path, flags);
+ if (ret)
goto fput_and_out;
- /* inode held in place by reference to path; dev by fget on fd */
+ /* inode held in place by reference to path; group by fget on fd */
inode = path.dentry->d_inode;
- dev = filp->private_data;
+ group = filp->private_data;
- mutex_lock(&dev->up_mutex);
- ret = inotify_find_update_watch(dev->ih, inode, mask);
- if (ret == -ENOENT)
- ret = create_watch(dev, inode, mask);
- mutex_unlock(&dev->up_mutex);
+ /* create/update an inode mark */
+ ret = inotify_update_watch(group, inode, mask);
+ if (unlikely(ret))
+ goto path_put_and_out;
+path_put_and_out:
path_put(&path);
fput_and_out:
fput_light(filp, fput_needed);
SYSCALL_DEFINE2(inotify_rm_watch, int, fd, __s32, wd)
{
+ struct fsnotify_group *group;
+ struct fsnotify_mark_entry *entry;
struct file *filp;
- struct inotify_device *dev;
- int ret, fput_needed;
+ int ret = 0, fput_needed;
filp = fget_light(fd, &fput_needed);
if (unlikely(!filp))
goto out;
}
- dev = filp->private_data;
+ group = filp->private_data;
- /* we free our watch data when we get IN_IGNORED */
- ret = inotify_rm_wd(dev->ih, wd);
+ spin_lock(&group->inotify_data.idr_lock);
+ entry = idr_find(&group->inotify_data.idr, wd);
+ if (unlikely(!entry)) {
+ spin_unlock(&group->inotify_data.idr_lock);
+ ret = -EINVAL;
+ goto out;
+ }
+ fsnotify_get_mark(entry);
+ spin_unlock(&group->inotify_data.idr_lock);
+
+ inotify_destroy_mark_entry(entry, group);
+ fsnotify_put_mark(entry);
out:
fput_light(filp, fput_needed);
}
static struct file_system_type inotify_fs_type = {
- .name = "inotifyfs",
- .get_sb = inotify_get_sb,
- .kill_sb = kill_anon_super,
+ .name = "inotifyfs",
+ .get_sb = inotify_get_sb,
+ .kill_sb = kill_anon_super,
};
/*
if (IS_ERR(inotify_mnt))
panic("inotify: kern_mount ret %ld!\n", PTR_ERR(inotify_mnt));
+ inotify_inode_mark_cachep = KMEM_CACHE(inotify_inode_mark_entry, SLAB_PANIC);
+ event_priv_cachep = KMEM_CACHE(inotify_event_private_data, SLAB_PANIC);
+ inotify_ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, FSNOTIFY_EVENT_NONE, NULL, 0);
+ if (!inotify_ignored_event)
+ panic("unable to allocate the inotify ignored event\n");
+
inotify_max_queued_events = 16384;
inotify_max_user_instances = 128;
inotify_max_user_watches = 8192;
- watch_cachep = kmem_cache_create("inotify_watch_cache",
- sizeof(struct inotify_user_watch),
- 0, SLAB_PANIC, NULL);
- event_cachep = kmem_cache_create("inotify_event_cache",
- sizeof(struct inotify_kernel_event),
- 0, SLAB_PANIC, NULL);
-
return 0;
}
-
module_init(inotify_user_setup);
--- /dev/null
+/*
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/*
+ * Basic idea behind the notification queue: An fsnotify group (like inotify)
+ * sends the userspace notification about events asyncronously some time after
+ * the event happened. When inotify gets an event it will need to add that
+ * event to the group notify queue. Since a single event might need to be on
+ * multiple group's notification queues we can't add the event directly to each
+ * queue and instead add a small "event_holder" to each queue. This event_holder
+ * has a pointer back to the original event. Since the majority of events are
+ * going to end up on one, and only one, notification queue we embed one
+ * event_holder into each event. This means we have a single allocation instead
+ * of always needing two. If the embedded event_holder is already in use by
+ * another group a new event_holder (from fsnotify_event_holder_cachep) will be
+ * allocated and used.
+ */
+
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/mutex.h>
+#include <linux/namei.h>
+#include <linux/path.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include <asm/atomic.h>
+
+#include <linux/fsnotify_backend.h>
+#include "fsnotify.h"
+
+static struct kmem_cache *fsnotify_event_cachep;
+static struct kmem_cache *fsnotify_event_holder_cachep;
+/*
+ * This is a magic event we send when the q is too full. Since it doesn't
+ * hold real event information we just keep one system wide and use it any time
+ * it is needed. It's refcnt is set 1 at kernel init time and will never
+ * get set to 0 so it will never get 'freed'
+ */
+static struct fsnotify_event q_overflow_event;
+static atomic_t fsnotify_sync_cookie = ATOMIC_INIT(0);
+
+/**
+ * fsnotify_get_cookie - return a unique cookie for use in synchronizing events.
+ * Called from fsnotify_move, which is inlined into filesystem modules.
+ */
+u32 fsnotify_get_cookie(void)
+{
+ return atomic_inc_return(&fsnotify_sync_cookie);
+}
+EXPORT_SYMBOL_GPL(fsnotify_get_cookie);
+
+/* return true if the notify queue is empty, false otherwise */
+bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group)
+{
+ BUG_ON(!mutex_is_locked(&group->notification_mutex));
+ return list_empty(&group->notification_list) ? true : false;
+}
+
+void fsnotify_get_event(struct fsnotify_event *event)
+{
+ atomic_inc(&event->refcnt);
+}
+
+void fsnotify_put_event(struct fsnotify_event *event)
+{
+ if (!event)
+ return;
+
+ if (atomic_dec_and_test(&event->refcnt)) {
+ if (event->data_type == FSNOTIFY_EVENT_PATH)
+ path_put(&event->path);
+
+ BUG_ON(!list_empty(&event->private_data_list));
+
+ kfree(event->file_name);
+ kmem_cache_free(fsnotify_event_cachep, event);
+ }
+}
+
+struct fsnotify_event_holder *fsnotify_alloc_event_holder(void)
+{
+ return kmem_cache_alloc(fsnotify_event_holder_cachep, GFP_KERNEL);
+}
+
+void fsnotify_destroy_event_holder(struct fsnotify_event_holder *holder)
+{
+ kmem_cache_free(fsnotify_event_holder_cachep, holder);
+}
+
+/*
+ * Find the private data that the group previously attached to this event when
+ * the group added the event to the notification queue (fsnotify_add_notify_event)
+ */
+struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group, struct fsnotify_event *event)
+{
+ struct fsnotify_event_private_data *lpriv;
+ struct fsnotify_event_private_data *priv = NULL;
+
+ assert_spin_locked(&event->lock);
+
+ list_for_each_entry(lpriv, &event->private_data_list, event_list) {
+ if (lpriv->group == group) {
+ priv = lpriv;
+ list_del(&priv->event_list);
+ break;
+ }
+ }
+ return priv;
+}
+
+/*
+ * Check if 2 events contain the same information. We do not compare private data
+ * but at this moment that isn't a problem for any know fsnotify listeners.
+ */
+static bool event_compare(struct fsnotify_event *old, struct fsnotify_event *new)
+{
+ if ((old->mask == new->mask) &&
+ (old->to_tell == new->to_tell) &&
+ (old->data_type == new->data_type)) {
+ switch (old->data_type) {
+ case (FSNOTIFY_EVENT_INODE):
+ if (old->inode == new->inode)
+ return true;
+ break;
+ case (FSNOTIFY_EVENT_PATH):
+ if ((old->path.mnt == new->path.mnt) &&
+ (old->path.dentry == new->path.dentry))
+ return true;
+ case (FSNOTIFY_EVENT_NONE):
+ return true;
+ };
+ }
+ return false;
+}
+
+/*
+ * Add an event to the group notification queue. The group can later pull this
+ * event off the queue to deal with. If the event is successfully added to the
+ * group's notification queue, a reference is taken on event.
+ */
+int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
+ struct fsnotify_event_private_data *priv)
+{
+ struct fsnotify_event_holder *holder = NULL;
+ struct list_head *list = &group->notification_list;
+ struct fsnotify_event_holder *last_holder;
+ struct fsnotify_event *last_event;
+
+ /* easy to tell if priv was attached to the event */
+ INIT_LIST_HEAD(&priv->event_list);
+
+ /*
+ * There is one fsnotify_event_holder embedded inside each fsnotify_event.
+ * Check if we expect to be able to use that holder. If not alloc a new
+ * holder.
+ * For the overflow event it's possible that something will use the in
+ * event holder before we get the lock so we may need to jump back and
+ * alloc a new holder, this can't happen for most events...
+ */
+ if (!list_empty(&event->holder.event_list)) {
+alloc_holder:
+ holder = fsnotify_alloc_event_holder();
+ if (!holder)
+ return -ENOMEM;
+ }
+
+ mutex_lock(&group->notification_mutex);
+
+ if (group->q_len >= group->max_events) {
+ event = &q_overflow_event;
+ /* sorry, no private data on the overflow event */
+ priv = NULL;
+ }
+
+ spin_lock(&event->lock);
+
+ if (list_empty(&event->holder.event_list)) {
+ if (unlikely(holder))
+ fsnotify_destroy_event_holder(holder);
+ holder = &event->holder;
+ } else if (unlikely(!holder)) {
+ /* between the time we checked above and got the lock the in
+ * event holder was used, go back and get a new one */
+ spin_unlock(&event->lock);
+ mutex_unlock(&group->notification_mutex);
+ goto alloc_holder;
+ }
+
+ if (!list_empty(list)) {
+ last_holder = list_entry(list->prev, struct fsnotify_event_holder, event_list);
+ last_event = last_holder->event;
+ if (event_compare(last_event, event)) {
+ spin_unlock(&event->lock);
+ mutex_unlock(&group->notification_mutex);
+ if (holder != &event->holder)
+ fsnotify_destroy_event_holder(holder);
+ return -EEXIST;
+ }
+ }
+
+ group->q_len++;
+ holder->event = event;
+
+ fsnotify_get_event(event);
+ list_add_tail(&holder->event_list, list);
+ if (priv)
+ list_add_tail(&priv->event_list, &event->private_data_list);
+ spin_unlock(&event->lock);
+ mutex_unlock(&group->notification_mutex);
+
+ wake_up(&group->notification_waitq);
+ return 0;
+}
+
+/*
+ * Remove and return the first event from the notification list. There is a
+ * reference held on this event since it was on the list. It is the responsibility
+ * of the caller to drop this reference.
+ */
+struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group)
+{
+ struct fsnotify_event *event;
+ struct fsnotify_event_holder *holder;
+
+ BUG_ON(!mutex_is_locked(&group->notification_mutex));
+
+ holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list);
+
+ event = holder->event;
+
+ spin_lock(&event->lock);
+ holder->event = NULL;
+ list_del_init(&holder->event_list);
+ spin_unlock(&event->lock);
+
+ /* event == holder means we are referenced through the in event holder */
+ if (holder != &event->holder)
+ fsnotify_destroy_event_holder(holder);
+
+ group->q_len--;
+
+ return event;
+}
+
+/*
+ * This will not remove the event, that must be done with fsnotify_remove_notify_event()
+ */
+struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group)
+{
+ struct fsnotify_event *event;
+ struct fsnotify_event_holder *holder;
+
+ BUG_ON(!mutex_is_locked(&group->notification_mutex));
+
+ holder = list_first_entry(&group->notification_list, struct fsnotify_event_holder, event_list);
+ event = holder->event;
+
+ return event;
+}
+
+/*
+ * Called when a group is being torn down to clean up any outstanding
+ * event notifications.
+ */
+void fsnotify_flush_notify(struct fsnotify_group *group)
+{
+ struct fsnotify_event *event;
+ struct fsnotify_event_private_data *priv;
+
+ mutex_lock(&group->notification_mutex);
+ while (!fsnotify_notify_queue_is_empty(group)) {
+ event = fsnotify_remove_notify_event(group);
+ /* if they don't implement free_event_priv they better not have attached any */
+ if (group->ops->free_event_priv) {
+ spin_lock(&event->lock);
+ priv = fsnotify_remove_priv_from_event(group, event);
+ spin_unlock(&event->lock);
+ if (priv)
+ group->ops->free_event_priv(priv);
+ }
+ fsnotify_put_event(event); /* matches fsnotify_add_notify_event */
+ }
+ mutex_unlock(&group->notification_mutex);
+}
+
+static void initialize_event(struct fsnotify_event *event)
+{
+ event->holder.event = NULL;
+ INIT_LIST_HEAD(&event->holder.event_list);
+ atomic_set(&event->refcnt, 1);
+
+ spin_lock_init(&event->lock);
+
+ event->path.dentry = NULL;
+ event->path.mnt = NULL;
+ event->inode = NULL;
+ event->data_type = FSNOTIFY_EVENT_NONE;
+
+ INIT_LIST_HEAD(&event->private_data_list);
+
+ event->to_tell = NULL;
+
+ event->file_name = NULL;
+ event->name_len = 0;
+
+ event->sync_cookie = 0;
+}
+
+/*
+ * fsnotify_create_event - Allocate a new event which will be sent to each
+ * group's handle_event function if the group was interested in this
+ * particular event.
+ *
+ * @to_tell the inode which is supposed to receive the event (sometimes a
+ * parent of the inode to which the event happened.
+ * @mask what actually happened.
+ * @data pointer to the object which was actually affected
+ * @data_type flag indication if the data is a file, path, inode, nothing...
+ * @name the filename, if available
+ */
+struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask, void *data,
+ int data_type, const char *name, u32 cookie)
+{
+ struct fsnotify_event *event;
+
+ event = kmem_cache_alloc(fsnotify_event_cachep, GFP_KERNEL);
+ if (!event)
+ return NULL;
+
+ initialize_event(event);
+
+ if (name) {
+ event->file_name = kstrdup(name, GFP_KERNEL);
+ if (!event->file_name) {
+ kmem_cache_free(fsnotify_event_cachep, event);
+ return NULL;
+ }
+ event->name_len = strlen(event->file_name);
+ }
+
+ event->sync_cookie = cookie;
+ event->to_tell = to_tell;
+
+ switch (data_type) {
+ case FSNOTIFY_EVENT_FILE: {
+ struct file *file = data;
+ struct path *path = &file->f_path;
+ event->path.dentry = path->dentry;
+ event->path.mnt = path->mnt;
+ path_get(&event->path);
+ event->data_type = FSNOTIFY_EVENT_PATH;
+ break;
+ }
+ case FSNOTIFY_EVENT_PATH: {
+ struct path *path = data;
+ event->path.dentry = path->dentry;
+ event->path.mnt = path->mnt;
+ path_get(&event->path);
+ event->data_type = FSNOTIFY_EVENT_PATH;
+ break;
+ }
+ case FSNOTIFY_EVENT_INODE:
+ event->inode = data;
+ event->data_type = FSNOTIFY_EVENT_INODE;
+ break;
+ case FSNOTIFY_EVENT_NONE:
+ event->inode = NULL;
+ event->path.dentry = NULL;
+ event->path.mnt = NULL;
+ break;
+ default:
+ BUG();
+ }
+
+ event->mask = mask;
+
+ return event;
+}
+
+__init int fsnotify_notification_init(void)
+{
+ fsnotify_event_cachep = KMEM_CACHE(fsnotify_event, SLAB_PANIC);
+ fsnotify_event_holder_cachep = KMEM_CACHE(fsnotify_event_holder, SLAB_PANIC);
+
+ initialize_event(&q_overflow_event);
+ q_overflow_event.mask = FS_Q_OVERFLOW;
+
+ return 0;
+}
+subsys_initcall(fsnotify_notification_init);
+
#define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */
#define DCACHE_UNHASHED 0x0010
-#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched */
+#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */
#define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */
+#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0080 /* Parent inode is watched by some fsnotify listener */
+
extern spinlock_t dcache_lock;
extern seqlock_t rename_lock;
struct dnotify_struct {
struct dnotify_struct * dn_next;
- unsigned long dn_mask;
+ __u32 dn_mask;
int dn_fd;
struct file * dn_filp;
fl_owner_t dn_owner;
#ifdef CONFIG_DNOTIFY
-extern void __inode_dir_notify(struct inode *, unsigned long);
+#define DNOTIFY_ALL_EVENTS (FS_DELETE | FS_DELETE_CHILD |\
+ FS_MODIFY | FS_MODIFY_CHILD |\
+ FS_ACCESS | FS_ACCESS_CHILD |\
+ FS_ATTRIB | FS_ATTRIB_CHILD |\
+ FS_CREATE | FS_DN_RENAME |\
+ FS_MOVED_FROM | FS_MOVED_TO)
+
extern void dnotify_flush(struct file *, fl_owner_t);
extern int fcntl_dirnotify(int, struct file *, unsigned long);
-extern void dnotify_parent(struct dentry *, unsigned long);
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
- if (inode->i_dnotify_mask & (event))
- __inode_dir_notify(inode, event);
-}
#else
-static inline void __inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
static inline void dnotify_flush(struct file *filp, fl_owner_t id)
{
}
return -EINVAL;
}
-static inline void dnotify_parent(struct dentry *dentry, unsigned long event)
-{
-}
-
-static inline void inode_dir_notify(struct inode *inode, unsigned long event)
-{
-}
-
#endif /* CONFIG_DNOTIFY */
#endif /* __KERNEL __ */
__u32 i_generation;
-#ifdef CONFIG_DNOTIFY
- unsigned long i_dnotify_mask; /* Directory notify events */
- struct dnotify_struct *i_dnotify; /* for directory notifications */
+#ifdef CONFIG_FSNOTIFY
+ __u32 i_fsnotify_mask; /* all events this inode cares about */
+ struct hlist_head i_fsnotify_mark_entries; /* fsnotify mark entries */
#endif
#ifdef CONFIG_INOTIFY
#include <linux/dnotify.h>
#include <linux/inotify.h>
+#include <linux/fsnotify_backend.h>
#include <linux/audit.h>
/*
static inline void fsnotify_d_instantiate(struct dentry *entry,
struct inode *inode)
{
+ __fsnotify_d_instantiate(entry, inode);
+
inotify_d_instantiate(entry, inode);
}
+/* Notify this dentry's parent about a child's events. */
+static inline void fsnotify_parent(struct dentry *dentry, __u32 mask)
+{
+ __fsnotify_parent(dentry, mask);
+
+ inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
+}
+
/*
* fsnotify_d_move - entry has been moved
* Called with dcache_lock and entry->d_lock held.
*/
static inline void fsnotify_d_move(struct dentry *entry)
{
+ /*
+ * On move we need to update entry->d_flags to indicate if the new parent
+ * cares about events from this entry.
+ */
+ __fsnotify_update_dcache_flags(entry);
+
inotify_d_move(entry);
}
+/*
+ * fsnotify_link_count - inode's link count changed
+ */
+static inline void fsnotify_link_count(struct inode *inode)
+{
+ inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
+
+ fsnotify(inode, FS_ATTRIB, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+}
+
/*
* fsnotify_move - file old_name at old_dir was moved to new_name at new_dir
*/
int isdir, struct inode *target, struct dentry *moved)
{
struct inode *source = moved->d_inode;
- u32 cookie = inotify_get_cookie();
+ u32 in_cookie = inotify_get_cookie();
+ u32 fs_cookie = fsnotify_get_cookie();
+ __u32 old_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_FROM);
+ __u32 new_dir_mask = (FS_EVENT_ON_CHILD | FS_MOVED_TO);
if (old_dir == new_dir)
- inode_dir_notify(old_dir, DN_RENAME);
- else {
- inode_dir_notify(old_dir, DN_DELETE);
- inode_dir_notify(new_dir, DN_CREATE);
- }
+ old_dir_mask |= FS_DN_RENAME;
- if (isdir)
+ if (isdir) {
isdir = IN_ISDIR;
- inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir,cookie,old_name,
+ old_dir_mask |= FS_IN_ISDIR;
+ new_dir_mask |= FS_IN_ISDIR;
+ }
+
+ inotify_inode_queue_event(old_dir, IN_MOVED_FROM|isdir, in_cookie, old_name,
source);
- inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, cookie, new_name,
+ inotify_inode_queue_event(new_dir, IN_MOVED_TO|isdir, in_cookie, new_name,
source);
+ fsnotify(old_dir, old_dir_mask, old_dir, FSNOTIFY_EVENT_INODE, old_name, fs_cookie);
+ fsnotify(new_dir, new_dir_mask, new_dir, FSNOTIFY_EVENT_INODE, new_name, fs_cookie);
+
if (target) {
inotify_inode_queue_event(target, IN_DELETE_SELF, 0, NULL, NULL);
inotify_inode_is_dead(target);
+
+ /* this is really a link_count change not a removal */
+ fsnotify_link_count(target);
}
if (source) {
inotify_inode_queue_event(source, IN_MOVE_SELF, 0, NULL, NULL);
+ fsnotify(source, FS_MOVE_SELF, moved->d_inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
audit_inode_child(new_name, moved, new_dir);
}
+/*
+ * fsnotify_inode_delete - and inode is being evicted from cache, clean up is needed
+ */
+static inline void fsnotify_inode_delete(struct inode *inode)
+{
+ __fsnotify_inode_delete(inode);
+}
+
/*
* fsnotify_nameremove - a filename was removed from a directory
*/
static inline void fsnotify_nameremove(struct dentry *dentry, int isdir)
{
+ __u32 mask = FS_DELETE;
+
if (isdir)
- isdir = IN_ISDIR;
- dnotify_parent(dentry, DN_DELETE);
- inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name);
+ mask |= FS_IN_ISDIR;
+
+ fsnotify_parent(dentry, mask);
}
/*
{
inotify_inode_queue_event(inode, IN_DELETE_SELF, 0, NULL, NULL);
inotify_inode_is_dead(inode);
-}
-/*
- * fsnotify_link_count - inode's link count changed
- */
-static inline void fsnotify_link_count(struct inode *inode)
-{
- inotify_inode_queue_event(inode, IN_ATTRIB, 0, NULL, NULL);
+ fsnotify(inode, FS_DELETE_SELF, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
+ __fsnotify_inode_delete(inode);
}
/*
*/
static inline void fsnotify_create(struct inode *inode, struct dentry *dentry)
{
- inode_dir_notify(inode, DN_CREATE);
inotify_inode_queue_event(inode, IN_CREATE, 0, dentry->d_name.name,
dentry->d_inode);
audit_inode_child(dentry->d_name.name, dentry, inode);
+
+ fsnotify(inode, FS_CREATE, dentry->d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
/*
*/
static inline void fsnotify_link(struct inode *dir, struct inode *inode, struct dentry *new_dentry)
{
- inode_dir_notify(dir, DN_CREATE);
inotify_inode_queue_event(dir, IN_CREATE, 0, new_dentry->d_name.name,
inode);
fsnotify_link_count(inode);
audit_inode_child(new_dentry->d_name.name, new_dentry, dir);
+
+ fsnotify(dir, FS_CREATE, inode, FSNOTIFY_EVENT_INODE, new_dentry->d_name.name, 0);
}
/*
*/
static inline void fsnotify_mkdir(struct inode *inode, struct dentry *dentry)
{
- inode_dir_notify(inode, DN_CREATE);
- inotify_inode_queue_event(inode, IN_CREATE | IN_ISDIR, 0,
- dentry->d_name.name, dentry->d_inode);
+ __u32 mask = (FS_CREATE | FS_IN_ISDIR);
+ struct inode *d_inode = dentry->d_inode;
+
+ inotify_inode_queue_event(inode, mask, 0, dentry->d_name.name, d_inode);
audit_inode_child(dentry->d_name.name, dentry, inode);
+
+ fsnotify(inode, mask, d_inode, FSNOTIFY_EVENT_INODE, dentry->d_name.name, 0);
}
/*
static inline void fsnotify_access(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_ACCESS;
+ __u32 mask = FS_ACCESS;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- dnotify_parent(dentry, DN_ACCESS);
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
static inline void fsnotify_modify(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_MODIFY;
+ __u32 mask = FS_MODIFY;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- dnotify_parent(dentry, DN_MODIFY);
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
static inline void fsnotify_open(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_OPEN;
+ __u32 mask = FS_OPEN;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
{
struct dentry *dentry = file->f_path.dentry;
struct inode *inode = dentry->d_inode;
- const char *name = dentry->d_name.name;
fmode_t mode = file->f_mode;
- u32 mask = (mode & FMODE_WRITE) ? IN_CLOSE_WRITE : IN_CLOSE_NOWRITE;
+ __u32 mask = (mode & FMODE_WRITE) ? FS_CLOSE_WRITE : FS_CLOSE_NOWRITE;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE, NULL, 0);
}
/*
static inline void fsnotify_xattr(struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- u32 mask = IN_ATTRIB;
+ __u32 mask = FS_ATTRIB;
if (S_ISDIR(inode->i_mode))
- mask |= IN_ISDIR;
+ mask |= FS_IN_ISDIR;
- inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name);
inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
/*
static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid)
{
struct inode *inode = dentry->d_inode;
- int dn_mask = 0;
- u32 in_mask = 0;
+ __u32 mask = 0;
+
+ if (ia_valid & ATTR_UID)
+ mask |= FS_ATTRIB;
+ if (ia_valid & ATTR_GID)
+ mask |= FS_ATTRIB;
+ if (ia_valid & ATTR_SIZE)
+ mask |= FS_MODIFY;
- if (ia_valid & ATTR_UID) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
- if (ia_valid & ATTR_GID) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
- if (ia_valid & ATTR_SIZE) {
- in_mask |= IN_MODIFY;
- dn_mask |= DN_MODIFY;
- }
/* both times implies a utime(s) call */
if ((ia_valid & (ATTR_ATIME | ATTR_MTIME)) == (ATTR_ATIME | ATTR_MTIME))
- {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- } else if (ia_valid & ATTR_ATIME) {
- in_mask |= IN_ACCESS;
- dn_mask |= DN_ACCESS;
- } else if (ia_valid & ATTR_MTIME) {
- in_mask |= IN_MODIFY;
- dn_mask |= DN_MODIFY;
- }
- if (ia_valid & ATTR_MODE) {
- in_mask |= IN_ATTRIB;
- dn_mask |= DN_ATTRIB;
- }
+ mask |= FS_ATTRIB;
+ else if (ia_valid & ATTR_ATIME)
+ mask |= FS_ACCESS;
+ else if (ia_valid & ATTR_MTIME)
+ mask |= FS_MODIFY;
+
+ if (ia_valid & ATTR_MODE)
+ mask |= FS_ATTRIB;
- if (dn_mask)
- dnotify_parent(dentry, dn_mask);
- if (in_mask) {
+ if (mask) {
if (S_ISDIR(inode->i_mode))
- in_mask |= IN_ISDIR;
- inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL);
- inotify_dentry_parent_queue_event(dentry, in_mask, 0,
- dentry->d_name.name);
+ mask |= FS_IN_ISDIR;
+ inotify_inode_queue_event(inode, mask, 0, NULL, NULL);
+
+ fsnotify_parent(dentry, mask);
+ fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
}
}
-#ifdef CONFIG_INOTIFY /* inotify helpers */
+#if defined(CONFIG_INOTIFY) || defined(CONFIG_FSNOTIFY) /* notify helpers */
/*
* fsnotify_oldname_init - save off the old filename before we change it
kfree(old_name);
}
-#else /* CONFIG_INOTIFY */
+#else /* CONFIG_INOTIFY || CONFIG_FSNOTIFY */
static inline const char *fsnotify_oldname_init(const char *name)
{
--- /dev/null
+/*
+ * Filesystem access notification for Linux
+ *
+ * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
+ */
+
+#ifndef __LINUX_FSNOTIFY_BACKEND_H
+#define __LINUX_FSNOTIFY_BACKEND_H
+
+#ifdef __KERNEL__
+
+#include <linux/idr.h> /* inotify uses this */
+#include <linux/fs.h> /* struct inode */
+#include <linux/list.h>
+#include <linux/path.h> /* struct path */
+#include <linux/spinlock.h>
+#include <linux/types.h>
+
+#include <asm/atomic.h>
+
+/*
+ * IN_* from inotfy.h lines up EXACTLY with FS_*, this is so we can easily
+ * convert between them. dnotify only needs conversion at watch creation
+ * so no perf loss there. fanotify isn't defined yet, so it can use the
+ * wholes if it needs more events.
+ */
+#define FS_ACCESS 0x00000001 /* File was accessed */
+#define FS_MODIFY 0x00000002 /* File was modified */
+#define FS_ATTRIB 0x00000004 /* Metadata changed */
+#define FS_CLOSE_WRITE 0x00000008 /* Writtable file was closed */
+#define FS_CLOSE_NOWRITE 0x00000010 /* Unwrittable file closed */
+#define FS_OPEN 0x00000020 /* File was opened */
+#define FS_MOVED_FROM 0x00000040 /* File was moved from X */
+#define FS_MOVED_TO 0x00000080 /* File was moved to Y */
+#define FS_CREATE 0x00000100 /* Subfile was created */
+#define FS_DELETE 0x00000200 /* Subfile was deleted */
+#define FS_DELETE_SELF 0x00000400 /* Self was deleted */
+#define FS_MOVE_SELF 0x00000800 /* Self was moved */
+
+#define FS_UNMOUNT 0x00002000 /* inode on umount fs */
+#define FS_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
+#define FS_IN_IGNORED 0x00008000 /* last inotify event here */
+
+#define FS_IN_ISDIR 0x40000000 /* event occurred against dir */
+#define FS_IN_ONESHOT 0x80000000 /* only send event once */
+
+#define FS_DN_RENAME 0x10000000 /* file renamed */
+#define FS_DN_MULTISHOT 0x20000000 /* dnotify multishot */
+
+/* This inode cares about things that happen to its children. Always set for
+ * dnotify and inotify. */
+#define FS_EVENT_ON_CHILD 0x08000000
+
+/* This is a list of all events that may get sent to a parernt based on fs event
+ * happening to inodes inside that directory */
+#define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
+ FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
+ FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
+ FS_DELETE)
+
+/* listeners that hard code group numbers near the top */
+#define DNOTIFY_GROUP_NUM UINT_MAX
+#define INOTIFY_GROUP_NUM (DNOTIFY_GROUP_NUM-1)
+
+struct fsnotify_group;
+struct fsnotify_event;
+struct fsnotify_mark_entry;
+struct fsnotify_event_private_data;
+
+/*
+ * Each group much define these ops. The fsnotify infrastructure will call
+ * these operations for each relevant group.
+ *
+ * should_send_event - given a group, inode, and mask this function determines
+ * if the group is interested in this event.
+ * handle_event - main call for a group to handle an fs event
+ * free_group_priv - called when a group refcnt hits 0 to clean up the private union
+ * freeing-mark - this means that a mark has been flagged to die when everything
+ * finishes using it. The function is supplied with what must be a
+ * valid group and inode to use to clean up.
+ */
+struct fsnotify_ops {
+ bool (*should_send_event)(struct fsnotify_group *group, struct inode *inode, __u32 mask);
+ int (*handle_event)(struct fsnotify_group *group, struct fsnotify_event *event);
+ void (*free_group_priv)(struct fsnotify_group *group);
+ void (*freeing_mark)(struct fsnotify_mark_entry *entry, struct fsnotify_group *group);
+ void (*free_event_priv)(struct fsnotify_event_private_data *priv);
+};
+
+/*
+ * A group is a "thing" that wants to receive notification about filesystem
+ * events. The mask holds the subset of event types this group cares about.
+ * refcnt on a group is up to the implementor and at any moment if it goes 0
+ * everything will be cleaned up.
+ */
+struct fsnotify_group {
+ /*
+ * global list of all groups receiving events from fsnotify.
+ * anchored by fsnotify_groups and protected by either fsnotify_grp_mutex
+ * or fsnotify_grp_srcu depending on write vs read.
+ */
+ struct list_head group_list;
+
+ /*
+ * Defines all of the event types in which this group is interested.
+ * This mask is a bitwise OR of the FS_* events from above. Each time
+ * this mask changes for a group (if it changes) the correct functions
+ * must be called to update the global structures which indicate global
+ * interest in event types.
+ */
+ __u32 mask;
+
+ /*
+ * How the refcnt is used is up to each group. When the refcnt hits 0
+ * fsnotify will clean up all of the resources associated with this group.
+ * As an example, the dnotify group will always have a refcnt=1 and that
+ * will never change. Inotify, on the other hand, has a group per
+ * inotify_init() and the refcnt will hit 0 only when that fd has been
+ * closed.
+ */
+ atomic_t refcnt; /* things with interest in this group */
+ unsigned int group_num; /* simply prevents accidental group collision */
+
+ const struct fsnotify_ops *ops; /* how this group handles things */
+
+ /* needed to send notification to userspace */
+ struct mutex notification_mutex; /* protect the notification_list */
+ struct list_head notification_list; /* list of event_holder this group needs to send to userspace */
+ wait_queue_head_t notification_waitq; /* read() on the notification file blocks on this waitq */
+ unsigned int q_len; /* events on the queue */
+ unsigned int max_events; /* maximum events allowed on the list */
+
+ /* stores all fastapth entries assoc with this group so they can be cleaned on unregister */
+ spinlock_t mark_lock; /* protect mark_entries list */
+ atomic_t num_marks; /* 1 for each mark entry and 1 for not being
+ * past the point of no return when freeing
+ * a group */
+ struct list_head mark_entries; /* all inode mark entries for this group */
+
+ /* prevents double list_del of group_list. protected by global fsnotify_grp_mutex */
+ bool on_group_list;
+
+ /* groups can define private fields here or use the void *private */
+ union {
+ void *private;
+#ifdef CONFIG_INOTIFY_USER
+ struct inotify_group_private_data {
+ spinlock_t idr_lock;
+ struct idr idr;
+ u32 last_wd;
+ struct fasync_struct *fa; /* async notification */
+ struct user_struct *user;
+ } inotify_data;
+#endif
+ };
+};
+
+/*
+ * A single event can be queued in multiple group->notification_lists.
+ *
+ * each group->notification_list will point to an event_holder which in turns points
+ * to the actual event that needs to be sent to userspace.
+ *
+ * Seemed cheaper to create a refcnt'd event and a small holder for every group
+ * than create a different event for every group
+ *
+ */
+struct fsnotify_event_holder {
+ struct fsnotify_event *event;
+ struct list_head event_list;
+};
+
+/*
+ * Inotify needs to tack data onto an event. This struct lets us later find the
+ * correct private data of the correct group.
+ */
+struct fsnotify_event_private_data {
+ struct fsnotify_group *group;
+ struct list_head event_list;
+};
+
+/*
+ * all of the information about the original object we want to now send to
+ * a group. If you want to carry more info from the accessing task to the
+ * listener this structure is where you need to be adding fields.
+ */
+struct fsnotify_event {
+ /*
+ * If we create an event we are also likely going to need a holder
+ * to link to a group. So embed one holder in the event. Means only
+ * one allocation for the common case where we only have one group
+ */
+ struct fsnotify_event_holder holder;
+ spinlock_t lock; /* protection for the associated event_holder and private_list */
+ /* to_tell may ONLY be dereferenced during handle_event(). */
+ struct inode *to_tell; /* either the inode the event happened to or its parent */
+ /*
+ * depending on the event type we should have either a path or inode
+ * We hold a reference on path, but NOT on inode. Since we have the ref on
+ * the path, it may be dereferenced at any point during this object's
+ * lifetime. That reference is dropped when this object's refcnt hits
+ * 0. If this event contains an inode instead of a path, the inode may
+ * ONLY be used during handle_event().
+ */
+ union {
+ struct path path;
+ struct inode *inode;
+ };
+/* when calling fsnotify tell it if the data is a path or inode */
+#define FSNOTIFY_EVENT_NONE 0
+#define FSNOTIFY_EVENT_PATH 1
+#define FSNOTIFY_EVENT_INODE 2
+#define FSNOTIFY_EVENT_FILE 3
+ int data_type; /* which of the above union we have */
+ atomic_t refcnt; /* how many groups still are using/need to send this event */
+ __u32 mask; /* the type of access, bitwise OR for FS_* event types */
+
+ u32 sync_cookie; /* used to corrolate events, namely inotify mv events */
+ char *file_name;
+ size_t name_len;
+
+ struct list_head private_data_list; /* groups can store private data here */
+};
+
+/*
+ * a mark is simply an entry attached to an in core inode which allows an
+ * fsnotify listener to indicate they are either no longer interested in events
+ * of a type matching mask or only interested in those events.
+ *
+ * these are flushed when an inode is evicted from core and may be flushed
+ * when the inode is modified (as seen by fsnotify_access). Some fsnotify users
+ * (such as dnotify) will flush these when the open fd is closed and not at
+ * inode eviction or modification.
+ */
+struct fsnotify_mark_entry {
+ __u32 mask; /* mask this mark entry is for */
+ /* we hold ref for each i_list and g_list. also one ref for each 'thing'
+ * in kernel that found and may be using this mark. */
+ atomic_t refcnt; /* active things looking at this mark */
+ struct inode *inode; /* inode this entry is associated with */
+ struct fsnotify_group *group; /* group this mark entry is for */
+ struct hlist_node i_list; /* list of mark_entries by inode->i_fsnotify_mark_entries */
+ struct list_head g_list; /* list of mark_entries by group->i_fsnotify_mark_entries */
+ spinlock_t lock; /* protect group, inode, and killme */
+ struct list_head free_i_list; /* tmp list used when freeing this mark */
+ struct list_head free_g_list; /* tmp list used when freeing this mark */
+ void (*free_mark)(struct fsnotify_mark_entry *entry); /* called on final put+free */
+};
+
+#ifdef CONFIG_FSNOTIFY
+
+/* called from the vfs helpers */
+
+/* main fsnotify call to send events */
+extern void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const char *name, u32 cookie);
+extern void __fsnotify_parent(struct dentry *dentry, __u32 mask);
+extern void __fsnotify_inode_delete(struct inode *inode);
+extern u32 fsnotify_get_cookie(void);
+
+static inline int fsnotify_inode_watches_children(struct inode *inode)
+{
+ /* FS_EVENT_ON_CHILD is set if the inode may care */
+ if (!(inode->i_fsnotify_mask & FS_EVENT_ON_CHILD))
+ return 0;
+ /* this inode might care about child events, does it care about the
+ * specific set of events that can happen on a child? */
+ return inode->i_fsnotify_mask & FS_EVENTS_POSS_ON_CHILD;
+}
+
+/*
+ * Update the dentry with a flag indicating the interest of its parent to receive
+ * filesystem events when those events happens to this dentry->d_inode.
+ */
+static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
+{
+ struct dentry *parent;
+
+ assert_spin_locked(&dcache_lock);
+ assert_spin_locked(&dentry->d_lock);
+
+ parent = dentry->d_parent;
+ if (fsnotify_inode_watches_children(parent->d_inode))
+ dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED;
+ else
+ dentry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED;
+}
+
+/*
+ * fsnotify_d_instantiate - instantiate a dentry for inode
+ * Called with dcache_lock held.
+ */
+static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (!inode)
+ return;
+
+ assert_spin_locked(&dcache_lock);
+
+ spin_lock(&dentry->d_lock);
+ __fsnotify_update_dcache_flags(dentry);
+ spin_unlock(&dentry->d_lock);
+}
+
+/* called from fsnotify listeners, such as fanotify or dnotify */
+
+/* must call when a group changes its ->mask */
+extern void fsnotify_recalc_global_mask(void);
+/* get a reference to an existing or create a new group */
+extern struct fsnotify_group *fsnotify_obtain_group(unsigned int group_num,
+ __u32 mask,
+ const struct fsnotify_ops *ops);
+/* run all marks associated with this group and update group->mask */
+extern void fsnotify_recalc_group_mask(struct fsnotify_group *group);
+/* drop reference on a group from fsnotify_obtain_group */
+extern void fsnotify_put_group(struct fsnotify_group *group);
+
+/* take a reference to an event */
+extern void fsnotify_get_event(struct fsnotify_event *event);
+extern void fsnotify_put_event(struct fsnotify_event *event);
+/* find private data previously attached to an event and unlink it */
+extern struct fsnotify_event_private_data *fsnotify_remove_priv_from_event(struct fsnotify_group *group,
+ struct fsnotify_event *event);
+
+/* attach the event to the group notification queue */
+extern int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_event *event,
+ struct fsnotify_event_private_data *priv);
+/* true if the group notification queue is empty */
+extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group);
+/* return, but do not dequeue the first event on the notification queue */
+extern struct fsnotify_event *fsnotify_peek_notify_event(struct fsnotify_group *group);
+/* return AND dequeue the first event on the notification queue */
+extern struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group *group);
+
+/* functions used to manipulate the marks attached to inodes */
+
+/* run all marks associated with an inode and update inode->i_fsnotify_mask */
+extern void fsnotify_recalc_inode_mask(struct inode *inode);
+extern void fsnotify_init_mark(struct fsnotify_mark_entry *entry, void (*free_mark)(struct fsnotify_mark_entry *entry));
+/* find (and take a reference) to a mark associated with group and inode */
+extern struct fsnotify_mark_entry *fsnotify_find_mark_entry(struct fsnotify_group *group, struct inode *inode);
+/* attach the mark to both the group and the inode */
+extern int fsnotify_add_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group, struct inode *inode);
+/* given a mark, flag it to be freed when all references are dropped */
+extern void fsnotify_destroy_mark_by_entry(struct fsnotify_mark_entry *entry);
+/* run all the marks in a group, and flag them to be freed */
+extern void fsnotify_clear_marks_by_group(struct fsnotify_group *group);
+extern void fsnotify_get_mark(struct fsnotify_mark_entry *entry);
+extern void fsnotify_put_mark(struct fsnotify_mark_entry *entry);
+extern void fsnotify_unmount_inodes(struct list_head *list);
+
+/* put here because inotify does some weird stuff when destroying watches */
+extern struct fsnotify_event *fsnotify_create_event(struct inode *to_tell, __u32 mask,
+ void *data, int data_is, const char *name,
+ u32 cookie);
+
+#else
+
+static inline void fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is,
+ const char *name, u32 cookie)
+{}
+
+static inline void __fsnotify_parent(struct dentry *dentry, __u32 mask)
+{}
+
+static inline void __fsnotify_inode_delete(struct inode *inode)
+{}
+
+static inline void __fsnotify_update_dcache_flags(struct dentry *dentry)
+{}
+
+static inline void __fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode)
+{}
+
+static inline u32 fsnotify_get_cookie(void)
+{
+ return 0;
+}
+
+static inline void fsnotify_unmount_inodes(struct list_head *list)
+{}
+
+#endif /* CONFIG_FSNOTIFY */
+
+#endif /* __KERNEL __ */
+
+#endif /* __LINUX_FSNOTIFY_BACKEND_H */
config AUDIT_TREE
def_bool y
- depends on AUDITSYSCALL && INOTIFY
+ depends on AUDITSYSCALL
+ select INOTIFY
menu "RCU Subsystem"
projects / mirror_ubuntu-bionic-kernel.git / commitdiff