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authorAl Viro <viro@zeniv.linux.org.uk>2014-05-01 10:30:00 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-16 20:51:53 -0700
commitcb55ed7f0759fdebffd52742b7b6baf2ae6824d6 (patch)
tree18c1ae9ddfa71dde33cf577a73a805600cd42288
parent065c70fd5fdca12785476e1f72fcffb0ce7fd165 (diff)
dentry_kill(): don't try to remove from shrink list
commit 41edf278fc2f042f4e22a12ed87d19c5201210e1 upstream. If the victim in on the shrink list, don't remove it from there. If shrink_dentry_list() manages to remove it from the list before we are done - fine, we'll just free it as usual. If not - mark it with new flag (DCACHE_MAY_FREE) and leave it there. Eventually, shrink_dentry_list() will get to it, remove the sucker from shrink list and call dentry_kill(dentry, 0). Which is where we'll deal with freeing. Since now dentry_kill(dentry, 0) may happen after or during dentry_kill(dentry, 1), we need to recognize that (by seeing DCACHE_DENTRY_KILLED already set), unlock everything and either free the sucker (in case DCACHE_MAY_FREE has been set) or leave it for ongoing dentry_kill(dentry, 1) to deal with. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Cc: "Nicholas A. Bellinger" <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/dcache.c27
-rw-r--r--include/linux/dcache.h2
2 files changed, 21 insertions, 8 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 16f9066ca7b8..099308a50d94 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -466,7 +466,14 @@ dentry_kill(struct dentry *dentry, int unlock_on_failure)
__releases(dentry->d_lock)
{
struct inode *inode;
- struct dentry *parent;
+ struct dentry *parent = NULL;
+ bool can_free = true;
+
+ if (unlikely(dentry->d_flags & DCACHE_DENTRY_KILLED)) {
+ can_free = dentry->d_flags & DCACHE_MAY_FREE;
+ spin_unlock(&dentry->d_lock);
+ goto out;
+ }
inode = dentry->d_inode;
if (inode && !spin_trylock(&inode->i_lock)) {
@@ -477,9 +484,7 @@ relock:
}
return dentry; /* try again with same dentry */
}
- if (IS_ROOT(dentry))
- parent = NULL;
- else
+ if (!IS_ROOT(dentry))
parent = dentry->d_parent;
if (parent && !spin_trylock(&parent->d_lock)) {
if (inode)
@@ -502,8 +507,6 @@ relock:
if (dentry->d_flags & DCACHE_LRU_LIST) {
if (!(dentry->d_flags & DCACHE_SHRINK_LIST))
d_lru_del(dentry);
- else
- d_shrink_del(dentry);
}
/* if it was on the hash then remove it */
__d_drop(dentry);
@@ -525,7 +528,15 @@ relock:
if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry);
- dentry_free(dentry);
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_flags & DCACHE_SHRINK_LIST) {
+ dentry->d_flags |= DCACHE_MAY_FREE;
+ can_free = false;
+ }
+ spin_unlock(&dentry->d_lock);
+out:
+ if (likely(can_free))
+ dentry_free(dentry);
return parent;
}
@@ -830,7 +841,7 @@ static void shrink_dentry_list(struct list_head *list)
* We found an inuse dentry which was not removed from
* the LRU because of laziness during lookup. Do not free it.
*/
- if (dentry->d_lockref.count) {
+ if ((int)dentry->d_lockref.count > 0) {
spin_unlock(&dentry->d_lock);
continue;
}
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 0f0eb1c1e676..2a23ecb4f71c 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -221,6 +221,8 @@ struct dentry_operations {
#define DCACHE_SYMLINK_TYPE 0x00300000 /* Symlink */
#define DCACHE_FILE_TYPE 0x00400000 /* Other file type */
+#define DCACHE_MAY_FREE 0x00800000
+
extern seqlock_t rename_lock;
static inline int dname_external(const struct dentry *dentry)