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authorYan, Zheng <zheng.z.yan@intel.com>2013-08-13 15:42:02 +0800
committerAl Viro <viro@zeniv.linux.org.uk>2013-09-03 22:50:28 -0400
commit590fb51f1cf99c4a48a3b1bd65885192e877b561 (patch)
tree62e706e81be88a9760a126b4270e2b09c03933a1 /fs
parent184cacabe274a0af65b3876e9cd95c9fdde069ea (diff)
downloadlinux-590fb51f1cf99c4a48a3b1bd65885192e877b561.tar.bz2
vfs: call d_op->d_prune() before unhashing dentry
The d_prune dentry operation is used to notify filesystem when VFS about to prune a hashed dentry from the dcache. There are three code paths that prune dentries: shrink_dcache_for_umount_subtree(), prune_dcache_sb() and d_prune_aliases(). For the d_prune_aliases() case, VFS unhashes the dentry first, then call the d_prune dentry operation. This confuses ceph_d_prune() (ceph uses the d_prune dentry operation to maintain a flag indicating whether the complete contents of a directory are in the dcache, pruning unhashed dentry does not affect dir's completeness) This patch fixes the issue by calling the d_prune dentry operation in d_prune_aliases(), before unhashing the dentry. Also make VFS only call the d_prune dentry operation for hashed dentry, to avoid calling the d_prune dentry operation twice when dentry is pruned by d_prune_aliases(). Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs')
-rw-r--r--fs/dcache.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 83cfb834db03..2e5f9ca83285 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -472,7 +472,7 @@ relock:
* inform the fs via d_prune that this dentry is about to be
* unhashed and destroyed.
*/
- if (dentry->d_flags & DCACHE_OP_PRUNE)
+ if ((dentry->d_flags & DCACHE_OP_PRUNE) && !d_unhashed(dentry))
dentry->d_op->d_prune(dentry);
dentry_lru_del(dentry);
@@ -719,6 +719,14 @@ restart:
hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
spin_lock(&dentry->d_lock);
if (!dentry->d_count) {
+ /*
+ * inform the fs via d_prune that this dentry
+ * is about to be unhashed and destroyed.
+ */
+ if ((dentry->d_flags & DCACHE_OP_PRUNE) &&
+ !d_unhashed(dentry))
+ dentry->d_op->d_prune(dentry);
+
__dget_dlock(dentry);
__d_drop(dentry);
spin_unlock(&dentry->d_lock);
@@ -907,7 +915,8 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
* inform the fs that this dentry is about to be
* unhashed and destroyed.
*/
- if (dentry->d_flags & DCACHE_OP_PRUNE)
+ if ((dentry->d_flags & DCACHE_OP_PRUNE) &&
+ !d_unhashed(dentry))
dentry->d_op->d_prune(dentry);
dentry_lru_del(dentry);