sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched...

[mirror_ubuntu-artful-kernel.git] / fs / overlayfs / copy_up.c

diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 36795eed40b09ee1bbb6766e65019b8d1c6695f0..a34aa7aa25637010b70271ec23a2186fe195747f 100644 (file)
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -15,7 +15,8 @@
 #include <linux/xattr.h>
 #include <linux/security.h>
 #include <linux/uaccess.h>
-#include <linux/sched.h>
+#include <linux/sched/signal.h>
+#include <linux/cred.h>
 #include <linux/namei.h>
 #include <linux/fdtable.h>
 #include <linux/ratelimit.h>
@@ -33,7 +34,7 @@ static int ovl_check_fd(const void *data, struct file *f, unsigned int fd)
 {
        const struct dentry *dentry = data;
 
-       if (f->f_inode == d_inode(dentry))
+       if (file_inode(f) == d_inode(dentry))
                pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n",
                                    f, fd, current->pid, current->comm);
        return 0;
@@ -153,6 +154,13 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
                goto out_fput;
        }
 
+       /* Try to use clone_file_range to clone up within the same fs */
+       error = vfs_clone_file_range(old_file, 0, new_file, 0, len);
+       if (!error)
+               goto out;
+       /* Couldn't clone, so now we try to copy the data */
+       error = 0;
+
        /* FIXME: copy up sparse files efficiently */
        while (len) {
                size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
@@ -177,7 +185,7 @@ static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
 
                len -= bytes;
        }
-
+out:
        if (!error)
                error = vfs_fsync(new_file, 0);
        fput(new_file);
@@ -231,10 +239,15 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
        struct inode *udir = upperdir->d_inode;
        struct dentry *newdentry = NULL;
        struct dentry *upper = NULL;
-       umode_t mode = stat->mode;
        int err;
        const struct cred *old_creds = NULL;
        struct cred *new_creds = NULL;
+       struct cattr cattr = {
+               /* Can't properly set mode on creation because of the umask */
+               .mode = stat->mode & S_IFMT,
+               .rdev = stat->rdev,
+               .link = link
+       };
 
        newdentry = ovl_lookup_temp(workdir, dentry);
        err = PTR_ERR(newdentry);
@@ -254,10 +267,7 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
        if (new_creds)
                old_creds = override_creds(new_creds);
 
-       /* Can't properly set mode on creation because of the umask */
-       stat->mode &= S_IFMT;
-       err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
-       stat->mode = mode;
+       err = ovl_create_real(wdir, newdentry, &cattr, NULL, true);
 
        if (new_creds) {
                revert_creds(old_creds);
@@ -296,12 +306,6 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
        ovl_dentry_update(dentry, newdentry);
        ovl_inode_update(d_inode(dentry), d_inode(newdentry));
        newdentry = NULL;
-
-       /*
-        * Non-directores become opaque when copied up.
-        */
-       if (!S_ISDIR(stat->mode))
-               ovl_dentry_set_opaque(dentry, true);
 out2:
        dput(upper);
 out1:
@@ -317,20 +321,14 @@ out_cleanup:
 /*
  * Copy up a single dentry
  *
- * Directory renames only allowed on "pure upper" (already created on
- * upper filesystem, never copied up).  Directories which are on lower or
- * are merged may not be renamed.  For these -EXDEV is returned and
- * userspace has to deal with it.  This means, when copying up a
- * directory we can rely on it and ancestors being stable.
- *
- * Non-directory renames start with copy up of source if necessary.  The
- * actual rename will only proceed once the copy up was successful.  Copy
- * up uses upper parent i_mutex for exclusion.  Since rename can change
- * d_parent it is possible that the copy up will lock the old parent.  At
- * that point the file will have already been copied up anyway.
+ * All renames start with copy up of source if necessary.  The actual
+ * rename will only proceed once the copy up was successful.  Copy up uses
+ * upper parent i_mutex for exclusion.  Since rename can change d_parent it
+ * is possible that the copy up will lock the old parent.  At that point
+ * the file will have already been copied up anyway.
  */
-int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
-                   struct path *lowerpath, struct kstat *stat)
+static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
+                          struct path *lowerpath, struct kstat *stat)
 {
        DEFINE_DELAYED_CALL(done);
        struct dentry *workdir = ovl_workdir(dentry);
@@ -339,7 +337,6 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
        struct path parentpath;
        struct dentry *lowerdentry = lowerpath->dentry;
        struct dentry *upperdir;
-       struct dentry *upperdentry;
        const char *link = NULL;
 
        if (WARN_ON(!workdir))
@@ -365,8 +362,7 @@ int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
                pr_err("overlayfs: failed to lock workdir+upperdir\n");
                goto out_unlock;
        }
-       upperdentry = ovl_dentry_upper(dentry);
-       if (upperdentry) {
+       if (ovl_dentry_upper(dentry)) {
                /* Raced with another copy-up?  Nothing to do, then... */
                err = 0;
                goto out_unlock;
@@ -385,7 +381,7 @@ out_unlock:
        return err;
 }
 
-int ovl_copy_up(struct dentry *dentry)
+int ovl_copy_up_flags(struct dentry *dentry, int flags)
 {
        int err = 0;
        const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
@@ -415,6 +411,9 @@ int ovl_copy_up(struct dentry *dentry)
 
                ovl_path_lower(next, &lowerpath);
                err = vfs_getattr(&lowerpath, &stat);
+               /* maybe truncate regular file. this has no effect on dirs */
+               if (flags & O_TRUNC)
+                       stat.size = 0;
                if (!err)
                        err = ovl_copy_up_one(parent, next, &lowerpath, &stat);
 
@@ -425,3 +424,8 @@ int ovl_copy_up(struct dentry *dentry)
 
        return err;
 }
+
+int ovl_copy_up(struct dentry *dentry)
+{
+       return ovl_copy_up_flags(dentry, 0);
+}