}
}
+/*
+ * Prevent concurrent writepages on inode
+ *
+ * This is done by adding a negative bias to the inode write counter
+ * and waiting for all pending writes to finish.
+ */
+void fuse_set_nowrite(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ BUG_ON(!mutex_is_locked(&inode->i_mutex));
+
+ spin_lock(&fc->lock);
+ BUG_ON(fi->writectr < 0);
+ fi->writectr += FUSE_NOWRITE;
+ spin_unlock(&fc->lock);
+ wait_event(fi->page_waitq, fi->writectr == FUSE_NOWRITE);
+}
+
+/*
+ * Allow writepages on inode
+ *
+ * Remove the bias from the writecounter and send any queued
+ * writepages.
+ */
+static void __fuse_release_nowrite(struct inode *inode)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ BUG_ON(fi->writectr != FUSE_NOWRITE);
+ fi->writectr = 0;
+ fuse_flush_writepages(inode);
+}
+
+void fuse_release_nowrite(struct inode *inode)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+
+ spin_lock(&fc->lock);
+ __fuse_release_nowrite(inode);
+ spin_unlock(&fc->lock);
+}
+
/*
* Set attributes, and at the same time refresh them.
*
struct fuse_req *req;
struct fuse_setattr_in inarg;
struct fuse_attr_out outarg;
+ bool is_truncate = false;
+ loff_t oldsize;
int err;
if (!fuse_allow_task(fc, current))
send_sig(SIGXFSZ, current, 0);
return -EFBIG;
}
+ is_truncate = true;
}
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
+ if (is_truncate)
+ fuse_set_nowrite(inode);
+
memset(&inarg, 0, sizeof(inarg));
memset(&outarg, 0, sizeof(outarg));
iattr_to_fattr(attr, &inarg);
if (err) {
if (err == -EINTR)
fuse_invalidate_attr(inode);
- return err;
+ goto error;
}
if ((inode->i_mode ^ outarg.attr.mode) & S_IFMT) {
make_bad_inode(inode);
- return -EIO;
+ err = -EIO;
+ goto error;
+ }
+
+ spin_lock(&fc->lock);
+ fuse_change_attributes_common(inode, &outarg.attr,
+ attr_timeout(&outarg));
+ oldsize = inode->i_size;
+ i_size_write(inode, outarg.attr.size);
+
+ if (is_truncate) {
+ /* NOTE: this may release/reacquire fc->lock */
+ __fuse_release_nowrite(inode);
+ }
+ spin_unlock(&fc->lock);
+
+ /*
+ * Only call invalidate_inode_pages2() after removing
+ * FUSE_NOWRITE, otherwise fuse_launder_page() would deadlock.
+ */
+ if (S_ISREG(inode->i_mode) && oldsize != outarg.attr.size) {
+ if (outarg.attr.size < oldsize)
+ fuse_truncate(inode->i_mapping, outarg.attr.size);
+ invalidate_inode_pages2(inode->i_mapping);
}
- fuse_change_attributes(inode, &outarg.attr, attr_timeout(&outarg), 0);
return 0;
+
+error:
+ if (is_truncate)
+ fuse_release_nowrite(inode);
+
+ return err;
}
static int fuse_setattr(struct dentry *entry, struct iattr *attr)
return (u64) v0 + ((u64) v1 << 32);
}
+/*
+ * Check if page is under writeback
+ *
+ * This is currently done by walking the list of writepage requests
+ * for the inode, which can be pretty inefficient.
+ */
+static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_req *req;
+ bool found = false;
+
+ spin_lock(&fc->lock);
+ list_for_each_entry(req, &fi->writepages, writepages_entry) {
+ pgoff_t curr_index;
+
+ BUG_ON(req->inode != inode);
+ curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
+ if (curr_index == index) {
+ found = true;
+ break;
+ }
+ }
+ spin_unlock(&fc->lock);
+
+ return found;
+}
+
+/*
+ * Wait for page writeback to be completed.
+ *
+ * Since fuse doesn't rely on the VM writeback tracking, this has to
+ * use some other means.
+ */
+static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
+{
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
+ return 0;
+}
+
static int fuse_flush(struct file *file, fl_owner_t id)
{
struct inode *inode = file->f_path.dentry->d_inode;
return err;
}
+/*
+ * Wait for all pending writepages on the inode to finish.
+ *
+ * This is currently done by blocking further writes with FUSE_NOWRITE
+ * and waiting for all sent writes to complete.
+ *
+ * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
+ * could conflict with truncation.
+ */
+static void fuse_sync_writes(struct inode *inode)
+{
+ fuse_set_nowrite(inode);
+ fuse_release_nowrite(inode);
+}
+
int fuse_fsync_common(struct file *file, struct dentry *de, int datasync,
int isdir)
{
if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
return 0;
+ /*
+ * Start writeback against all dirty pages of the inode, then
+ * wait for all outstanding writes, before sending the FSYNC
+ * request.
+ */
+ err = write_inode_now(inode, 0);
+ if (err)
+ return err;
+
+ fuse_sync_writes(inode);
+
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
if (is_bad_inode(inode))
goto out;
+ /*
+ * Page writeback can extend beyond the liftime of the
+ * page-cache page, so make sure we read a properly synced
+ * page.
+ */
+ fuse_wait_on_page_writeback(inode, page->index);
+
req = fuse_get_req(fc);
err = PTR_ERR(req);
if (IS_ERR(req))
struct inode *inode = data->inode;
struct fuse_conn *fc = get_fuse_conn(inode);
+ fuse_wait_on_page_writeback(inode, page->index);
+
if (req->num_pages &&
(req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
(req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
}
static void fuse_write_fill(struct fuse_req *req, struct file *file,
- struct inode *inode, loff_t pos, size_t count,
- int writepage)
+ struct fuse_file *ff, struct inode *inode,
+ loff_t pos, size_t count, int writepage)
{
struct fuse_conn *fc = get_fuse_conn(inode);
- struct fuse_file *ff = file->private_data;
struct fuse_write_in *inarg = &req->misc.write.in;
struct fuse_write_out *outarg = &req->misc.write.out;
inarg->offset = pos;
inarg->size = count;
inarg->write_flags = writepage ? FUSE_WRITE_CACHE : 0;
- inarg->flags = file->f_flags;
+ inarg->flags = file ? file->f_flags : 0;
req->in.h.opcode = FUSE_WRITE;
req->in.h.nodeid = get_node_id(inode);
req->in.argpages = 1;
fl_owner_t owner)
{
struct fuse_conn *fc = get_fuse_conn(inode);
- fuse_write_fill(req, file, inode, pos, count, 0);
+ fuse_write_fill(req, file, file->private_data, inode, pos, count, 0);
if (owner != NULL) {
struct fuse_write_in *inarg = &req->misc.write.in;
inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
if (is_bad_inode(inode))
return -EIO;
+ /*
+ * Make sure writepages on the same page are not mixed up with
+ * plain writes.
+ */
+ fuse_wait_on_page_writeback(inode, page->index);
+
req = fuse_get_req(fc);
if (IS_ERR(req))
return PTR_ERR(req);
return res;
}
-static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
+static void fuse_writepage_free(struct fuse_conn *fc, struct fuse_req *req)
{
- if ((vma->vm_flags & VM_SHARED)) {
- if ((vma->vm_flags & VM_WRITE))
- return -ENODEV;
- else
- vma->vm_flags &= ~VM_MAYWRITE;
+ __free_page(req->pages[0]);
+ fuse_file_put(req->ff);
+ fuse_put_request(fc, req);
+}
+
+static void fuse_writepage_finish(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct inode *inode = req->inode;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
+
+ list_del(&req->writepages_entry);
+ dec_bdi_stat(bdi, BDI_WRITEBACK);
+ dec_zone_page_state(req->pages[0], NR_WRITEBACK_TEMP);
+ bdi_writeout_inc(bdi);
+ wake_up(&fi->page_waitq);
+}
+
+/* Called under fc->lock, may release and reacquire it */
+static void fuse_send_writepage(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct fuse_inode *fi = get_fuse_inode(req->inode);
+ loff_t size = i_size_read(req->inode);
+ struct fuse_write_in *inarg = &req->misc.write.in;
+
+ if (!fc->connected)
+ goto out_free;
+
+ if (inarg->offset + PAGE_CACHE_SIZE <= size) {
+ inarg->size = PAGE_CACHE_SIZE;
+ } else if (inarg->offset < size) {
+ inarg->size = size & (PAGE_CACHE_SIZE - 1);
+ } else {
+ /* Got truncated off completely */
+ goto out_free;
}
- return generic_file_mmap(file, vma);
+
+ req->in.args[1].size = inarg->size;
+ fi->writectr++;
+ request_send_background_locked(fc, req);
+ return;
+
+ out_free:
+ fuse_writepage_finish(fc, req);
+ spin_unlock(&fc->lock);
+ fuse_writepage_free(fc, req);
+ spin_lock(&fc->lock);
}
-static int fuse_set_page_dirty(struct page *page)
+/*
+ * If fi->writectr is positive (no truncate or fsync going on) send
+ * all queued writepage requests.
+ *
+ * Called with fc->lock
+ */
+void fuse_flush_writepages(struct inode *inode)
{
- printk("fuse_set_page_dirty: should not happen\n");
- dump_stack();
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_req *req;
+
+ while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) {
+ req = list_entry(fi->queued_writes.next, struct fuse_req, list);
+ list_del_init(&req->list);
+ fuse_send_writepage(fc, req);
+ }
+}
+
+static void fuse_writepage_end(struct fuse_conn *fc, struct fuse_req *req)
+{
+ struct inode *inode = req->inode;
+ struct fuse_inode *fi = get_fuse_inode(inode);
+
+ mapping_set_error(inode->i_mapping, req->out.h.error);
+ spin_lock(&fc->lock);
+ fi->writectr--;
+ fuse_writepage_finish(fc, req);
+ spin_unlock(&fc->lock);
+ fuse_writepage_free(fc, req);
+}
+
+static int fuse_writepage_locked(struct page *page)
+{
+ struct address_space *mapping = page->mapping;
+ struct inode *inode = mapping->host;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_req *req;
+ struct fuse_file *ff;
+ struct page *tmp_page;
+
+ set_page_writeback(page);
+
+ req = fuse_request_alloc_nofs();
+ if (!req)
+ goto err;
+
+ tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
+ if (!tmp_page)
+ goto err_free;
+
+ spin_lock(&fc->lock);
+ BUG_ON(list_empty(&fi->write_files));
+ ff = list_entry(fi->write_files.next, struct fuse_file, write_entry);
+ req->ff = fuse_file_get(ff);
+ spin_unlock(&fc->lock);
+
+ fuse_write_fill(req, NULL, ff, inode, page_offset(page), 0, 1);
+
+ copy_highpage(tmp_page, page);
+ req->num_pages = 1;
+ req->pages[0] = tmp_page;
+ req->page_offset = 0;
+ req->end = fuse_writepage_end;
+ req->inode = inode;
+
+ inc_bdi_stat(mapping->backing_dev_info, BDI_WRITEBACK);
+ inc_zone_page_state(tmp_page, NR_WRITEBACK_TEMP);
+ end_page_writeback(page);
+
+ spin_lock(&fc->lock);
+ list_add(&req->writepages_entry, &fi->writepages);
+ list_add_tail(&req->list, &fi->queued_writes);
+ fuse_flush_writepages(inode);
+ spin_unlock(&fc->lock);
+
+ return 0;
+
+err_free:
+ fuse_request_free(req);
+err:
+ end_page_writeback(page);
+ return -ENOMEM;
+}
+
+static int fuse_writepage(struct page *page, struct writeback_control *wbc)
+{
+ int err;
+
+ err = fuse_writepage_locked(page);
+ unlock_page(page);
+
+ return err;
+}
+
+static int fuse_launder_page(struct page *page)
+{
+ int err = 0;
+ if (clear_page_dirty_for_io(page)) {
+ struct inode *inode = page->mapping->host;
+ err = fuse_writepage_locked(page);
+ if (!err)
+ fuse_wait_on_page_writeback(inode, page->index);
+ }
+ return err;
+}
+
+/*
+ * Write back dirty pages now, because there may not be any suitable
+ * open files later
+ */
+static void fuse_vma_close(struct vm_area_struct *vma)
+{
+ filemap_write_and_wait(vma->vm_file->f_mapping);
+}
+
+/*
+ * Wait for writeback against this page to complete before allowing it
+ * to be marked dirty again, and hence written back again, possibly
+ * before the previous writepage completed.
+ *
+ * Block here, instead of in ->writepage(), so that the userspace fs
+ * can only block processes actually operating on the filesystem.
+ *
+ * Otherwise unprivileged userspace fs would be able to block
+ * unrelated:
+ *
+ * - page migration
+ * - sync(2)
+ * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER
+ */
+static int fuse_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+{
+ /*
+ * Don't use page->mapping as it may become NULL from a
+ * concurrent truncate.
+ */
+ struct inode *inode = vma->vm_file->f_mapping->host;
+
+ fuse_wait_on_page_writeback(inode, page->index);
+ return 0;
+}
+
+static struct vm_operations_struct fuse_file_vm_ops = {
+ .close = fuse_vma_close,
+ .fault = filemap_fault,
+ .page_mkwrite = fuse_page_mkwrite,
+};
+
+static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) {
+ struct inode *inode = file->f_dentry->d_inode;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ struct fuse_file *ff = file->private_data;
+ /*
+ * file may be written through mmap, so chain it onto the
+ * inodes's write_file list
+ */
+ spin_lock(&fc->lock);
+ if (list_empty(&ff->write_entry))
+ list_add(&ff->write_entry, &fi->write_files);
+ spin_unlock(&fc->lock);
+ }
+ file_accessed(file);
+ vma->vm_ops = &fuse_file_vm_ops;
return 0;
}
static const struct address_space_operations fuse_file_aops = {
.readpage = fuse_readpage,
+ .writepage = fuse_writepage,
+ .launder_page = fuse_launder_page,
.write_begin = fuse_write_begin,
.write_end = fuse_write_end,
.readpages = fuse_readpages,
- .set_page_dirty = fuse_set_page_dirty,
+ .set_page_dirty = __set_page_dirty_nobuffers,
.bmap = fuse_bmap,
};
#include <linux/mm.h>
#include <linux/backing-dev.h>
#include <linux/mutex.h>
+#include <linux/rwsem.h>
/** Max number of pages that can be used in a single read request */
#define FUSE_MAX_PAGES_PER_REQ 32
/** Congestion starts at 75% of maximum */
#define FUSE_CONGESTION_THRESHOLD (FUSE_MAX_BACKGROUND * 75 / 100)
+/** Bias for fi->writectr, meaning new writepages must not be sent */
+#define FUSE_NOWRITE INT_MIN
+
/** It could be as large as PATH_MAX, but would that have any uses? */
#define FUSE_NAME_MAX 1024
/** Files usable in writepage. Protected by fc->lock */
struct list_head write_files;
+
+ /** Writepages pending on truncate or fsync */
+ struct list_head queued_writes;
+
+ /** Number of sent writes, a negative bias (FUSE_NOWRITE)
+ * means more writes are blocked */
+ int writectr;
+
+ /** Waitq for writepage completion */
+ wait_queue_head_t page_waitq;
+
+ /** List of writepage requestst (pending or sent) */
+ struct list_head writepages;
};
/** FUSE specific file data */
/** File used in the request (or NULL) */
struct fuse_file *ff;
+ /** Inode used in the request or NULL */
+ struct inode *inode;
+
+ /** Link on fi->writepages */
+ struct list_head writepages_entry;
+
/** Request completion callback */
void (*end)(struct fuse_conn *, struct fuse_req *);
void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
u64 attr_valid, u64 attr_version);
+void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
+ u64 attr_valid);
+
+void fuse_truncate(struct address_space *mapping, loff_t offset);
+
/**
* Initialize the client device
*/
*/
struct fuse_req *fuse_request_alloc(void);
+struct fuse_req *fuse_request_alloc_nofs(void);
+
/**
* Free a request
*/
*/
void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
+void request_send_background_locked(struct fuse_conn *fc, struct fuse_req *req);
+
/* Abort all requests */
void fuse_abort_conn(struct fuse_conn *fc);
int fuse_update_attributes(struct inode *inode, struct kstat *stat,
struct file *file, bool *refreshed);
+
+void fuse_flush_writepages(struct inode *inode);
+
+void fuse_set_nowrite(struct inode *inode);
+void fuse_release_nowrite(struct inode *inode);
fi->nodeid = 0;
fi->nlookup = 0;
fi->attr_version = 0;
+ fi->writectr = 0;
INIT_LIST_HEAD(&fi->write_files);
+ INIT_LIST_HEAD(&fi->queued_writes);
+ INIT_LIST_HEAD(&fi->writepages);
+ init_waitqueue_head(&fi->page_waitq);
fi->forget_req = fuse_request_alloc();
if (!fi->forget_req) {
kmem_cache_free(fuse_inode_cachep, inode);
{
struct fuse_inode *fi = get_fuse_inode(inode);
BUG_ON(!list_empty(&fi->write_files));
+ BUG_ON(!list_empty(&fi->queued_writes));
if (fi->forget_req)
fuse_request_free(fi->forget_req);
kmem_cache_free(fuse_inode_cachep, inode);
return 0;
}
-static void fuse_truncate(struct address_space *mapping, loff_t offset)
+void fuse_truncate(struct address_space *mapping, loff_t offset)
{
/* See vmtruncate() */
unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
}
-
-void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
- u64 attr_valid, u64 attr_version)
+void fuse_change_attributes_common(struct inode *inode, struct fuse_attr *attr,
+ u64 attr_valid)
{
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_inode *fi = get_fuse_inode(inode);
- loff_t oldsize;
- spin_lock(&fc->lock);
- if (attr_version != 0 && fi->attr_version > attr_version) {
- spin_unlock(&fc->lock);
- return;
- }
fi->attr_version = ++fc->attr_version;
fi->i_time = attr_valid;
fi->orig_i_mode = inode->i_mode;
if (!(fc->flags & FUSE_DEFAULT_PERMISSIONS))
inode->i_mode &= ~S_ISVTX;
+}
+
+void fuse_change_attributes(struct inode *inode, struct fuse_attr *attr,
+ u64 attr_valid, u64 attr_version)
+{
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_inode *fi = get_fuse_inode(inode);
+ loff_t oldsize;
+
+ spin_lock(&fc->lock);
+ if (attr_version != 0 && fi->attr_version > attr_version) {
+ spin_unlock(&fc->lock);
+ return;
+ }
+
+ fuse_change_attributes_common(inode, attr, attr_valid);
oldsize = inode->i_size;
i_size_write(inode, attr->size);
atomic_set(&fc->num_waiting, 0);
fc->bdi.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
fc->bdi.unplug_io_fn = default_unplug_io_fn;
+ /* fuse does it's own writeback accounting */
+ fc->bdi.capabilities = BDI_CAP_NO_ACCT_WB;
fc->dev = sb->s_dev;
err = bdi_init(&fc->bdi);
if (err)
err = bdi_register_dev(&fc->bdi, fc->dev);
if (err)
goto error_bdi_destroy;
+ /*
+ * For a single fuse filesystem use max 1% of dirty +
+ * writeback threshold.
+ *
+ * This gives about 1M of write buffer for memory maps on a
+ * machine with 1G and 10% dirty_ratio, which should be more
+ * than enough.
+ *
+ * Privileged users can raise it by writing to
+ *
+ * /sys/class/bdi/<bdi>/max_ratio
+ */
+ bdi_set_max_ratio(&fc->bdi, 1);
fc->reqctr = 0;
fc->blocked = 1;
fc->attr_version = 1;
projects / mirror_ubuntu-eoan-kernel.git / commitdiff