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| author | Yan, Zheng <zheng.z.yan@intel.com> | 2013-08-13 15:42:02 +0800 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-09-03 22:50:28 -0400 |
| commit | 590fb51f1cf99c4a48a3b1bd65885192e877b561 (patch) | |
| tree | 62e706e81be88a9760a126b4270e2b09c03933a1 /fs/dcache.c | |
| parent | 184cacabe274a0af65b3876e9cd95c9fdde069ea (diff) | |
| download | lwn-590fb51f1cf99c4a48a3b1bd65885192e877b561.tar.gz lwn-590fb51f1cf99c4a48a3b1bd65885192e877b561.zip | |
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/dcache.c')
| -rw-r--r-- | fs/dcache.c | 13 |
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); |