From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>
When pruning a dentry, its ancestor dentry can also be pruned. But
the ancestor dentry does not go through dput(), so it does not get
put on the dentry LRU. Hence associating d_prune with removing the
dentry from the LRU is the wrong.
The fix is remove dentry_lru_prune(). Modify all its callers to use
dentry_lru_del() and call file system's d_prune() callback directly.
Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
---
fs/dcache.c | 31 +++++++++----------------------
1 file changed, 9 insertions(+), 22 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 19153a0..ceedd04 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -337,23 +337,6 @@ static void dentry_lru_del(struct dentry *dentry)
}
}
-/*
- * Remove a dentry that is unreferenced and about to be pruned
- * (unhashed and destroyed) from the LRU, and inform the file system.
- * This wrapper should be called _prior_ to unhashing a victim dentry.
- */
-static void dentry_lru_prune(struct dentry *dentry)
-{
- if (!list_empty(&dentry->d_lru)) {
- if (dentry->d_flags & DCACHE_OP_PRUNE)
- dentry->d_op->d_prune(dentry);
-
- spin_lock(&dcache_lru_lock);
- __dentry_lru_del(dentry);
- spin_unlock(&dcache_lru_lock);
- }
-}
-
static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list)
{
spin_lock(&dcache_lru_lock);
@@ -486,11 +469,13 @@ relock:
if (ref)
dentry->d_count--;
/*
- * if dentry was on the d_lru list delete it from there.
* inform the fs via d_prune that this dentry is about to be
* unhashed and destroyed.
*/
- dentry_lru_prune(dentry);
+ if (dentry->d_flags & DCACHE_OP_PRUNE)
+ dentry->d_op->d_prune(dentry);
+
+ dentry_lru_del(dentry);
/* if it was on the hash then remove it */
__d_drop(dentry);
return d_kill(dentry, parent);
@@ -921,11 +906,13 @@ static void shrink_dcache_for_umount_subtree(struct dentry *dentry)
struct inode *inode;
/*
- * remove the dentry from the lru, and inform
- * the fs that this dentry is about to be
+ * inform the fs that this dentry is about to be
* unhashed and destroyed.
*/
- dentry_lru_prune(dentry);
+ if (dentry->d_flags & DCACHE_OP_PRUNE)
+ dentry->d_op->d_prune(dentry);
+
+ dentry_lru_del(dentry);
__d_shrink(dentry);
if (dentry->d_count != 0) {
--
1.7.11.7
--
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