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ceph: introduce a new inode flag indicating if cached dentries are ordered

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After creating/deleting/renaming file, offsets of sibling dentries may
change. So we can not use cached dentries to satisfy readdir. But we can
still use the cached dentries to conclude -ENOENT for lookup.

This patch introduces a new inode flag indicating if child dentries are
ordered. The flag is set at the same time marking a directory complete.
After creating/deleting/renaming file, we clear the flag on directory
inode. This prevents ceph_readdir() from using cached dentries to satisfy
readdir syscall.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
This commit is contained in:
Yan, Zheng
2014-10-21 18:09:56 -07:00
committed by Ilya Dryomov
parent 4965fc38c4
commit 70db4f3629
3 changed files with 55 additions and 19 deletions
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23
fs/ceph/dir.c
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@@ -183,7 +183,7 @@ more:
spin_unlock(&parent->d_lock);
/* make sure a dentry wasn't dropped while we didn't have parent lock */
if (!ceph_dir_is_complete(dir)) {
if (!ceph_dir_is_complete_ordered(dir)) {
dout(" lost dir complete on %p; falling back to mds\n", dir);
dput(dentry);
err = -EAGAIN;
@@ -261,10 +261,6 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
/* always start with . and .. */
if (ctx->pos == 0) {
/* note dir version at start of readdir so we can tell
* if any dentries get dropped */
fi->dir_release_count = atomic_read(&ci->i_release_count);
dout("readdir off 0 -> '.'\n");
if (!dir_emit(ctx, ".", 1,
ceph_translate_ino(inode->i_sb, inode->i_ino),
@@ -289,7 +285,7 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
if ((ctx->pos == 2 || fi->dentry) &&
!ceph_test_mount_opt(fsc, NOASYNCREADDIR) &&
ceph_snap(inode) != CEPH_SNAPDIR &&
__ceph_dir_is_complete(ci) &&
__ceph_dir_is_complete_ordered(ci) &&
__ceph_caps_issued_mask(ci, CEPH_CAP_FILE_SHARED, 1)) {
u32 shared_gen = ci->i_shared_gen;
spin_unlock(&ci->i_ceph_lock);
@@ -312,6 +308,13 @@ static int ceph_readdir(struct file *file, struct dir_context *ctx)
/* proceed with a normal readdir */
if (ctx->pos == 2) {
/* note dir version at start of readdir so we can tell
* if any dentries get dropped */
fi->dir_release_count = atomic_read(&ci->i_release_count);
fi->dir_ordered_count = ci->i_ordered_count;
}
more:
/* do we have the correct frag content buffered? */
if (fi->frag != frag || fi->last_readdir == NULL) {
@@ -446,8 +449,12 @@ more:
*/
spin_lock(&ci->i_ceph_lock);
if (atomic_read(&ci->i_release_count) == fi->dir_release_count) {
dout(" marking %p complete\n", inode);
__ceph_dir_set_complete(ci, fi->dir_release_count);
if (ci->i_ordered_count == fi->dir_ordered_count)
dout(" marking %p complete and ordered\n", inode);
else
dout(" marking %p complete\n", inode);
__ceph_dir_set_complete(ci, fi->dir_release_count,
fi->dir_ordered_count);
}
spin_unlock(&ci->i_ceph_lock);