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authorMiklos Szeredi <mszeredi@suse.cz>2008-07-02 21:30:15 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2008-07-26 20:53:05 -0400
commitd70b67c8bc72ee23b55381bd6a884f4796692f77 (patch)
treec15055c81f21b7863318e1e6f8a9620afaeb3327
parenta048d3aff8b828b6c0fa7ddd90a531248ab4e0f9 (diff)
[patch] vfs: fix lookup on deleted directory
Lookup can install a child dentry for a deleted directory. This keeps the directory dentry alive, and the inode pinned in the cache and on disk, even after all external references have gone away. This isn't a big problem normally, since memory pressure or umount will clear out the directory dentry and its children, releasing the inode. But for UBIFS this causes problems because its orphan area can overflow. Fix this by returning ENOENT for all lookups on a S_DEAD directory before creating a child dentry. Thanks to Zoltan Sogor for noticing this while testing UBIFS, and Artem for the excellent analysis of the problem and testing. Reported-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Tested-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namei.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 01e67dddcc3d..3b26a240ade9 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -519,7 +519,14 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s
*/
result = d_lookup(parent, name);
if (!result) {
- struct dentry * dentry = d_alloc(parent, name);
+ struct dentry *dentry;
+
+ /* Don't create child dentry for a dead directory. */
+ result = ERR_PTR(-ENOENT);
+ if (IS_DEADDIR(dir))
+ goto out_unlock;
+
+ dentry = d_alloc(parent, name);
result = ERR_PTR(-ENOMEM);
if (dentry) {
result = dir->i_op->lookup(dir, dentry, nd);
@@ -528,6 +535,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s
else
result = dentry;
}
+out_unlock:
mutex_unlock(&dir->i_mutex);
return result;
}
@@ -1317,7 +1325,14 @@ static struct dentry *__lookup_hash(struct qstr *name,
dentry = cached_lookup(base, name, nd);
if (!dentry) {
- struct dentry *new = d_alloc(base, name);
+ struct dentry *new;
+
+ /* Don't create child dentry for a dead directory. */
+ dentry = ERR_PTR(-ENOENT);
+ if (IS_DEADDIR(inode))
+ goto out;
+
+ new = d_alloc(base, name);
dentry = ERR_PTR(-ENOMEM);
if (!new)
goto out;