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authorAl Viro <viro@zeniv.linux.org.uk>2018-05-11 04:59:45 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2018-05-21 20:30:10 +0200
commit9c3e9025a3f7ed25c99a0add8af65431c8043800 (patch)
treed8f892f5750d1aea00dcef9d9f7ea1719f11a6ce /fs/cachefiles
parentunfuck sysfs_mount() (diff)
downloadlinux-9c3e9025a3f7ed25c99a0add8af65431c8043800.tar.xz
linux-9c3e9025a3f7ed25c99a0add8af65431c8043800.zip
cachefiles: vfs_mkdir() might succeed leaving dentry negative unhashed
That can (and does, on some filesystems) happen - ->mkdir() (and thus vfs_mkdir()) can legitimately leave its argument negative and just unhash it, counting upon the lookup to pick the object we'd created next time we try to look at that name. Some vfs_mkdir() callers forget about that possibility... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/cachefiles')
-rw-r--r--fs/cachefiles/namei.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 0daa1e3fe0df..ab0bbe93b398 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -572,6 +572,11 @@ lookup_again:
if (ret < 0)
goto create_error;
+ if (unlikely(d_unhashed(next))) {
+ dput(next);
+ inode_unlock(d_inode(dir));
+ goto lookup_again;
+ }
ASSERT(d_backing_inode(next));
_debug("mkdir -> %p{%p{ino=%lu}}",
@@ -764,6 +769,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
/* search the current directory for the element name */
inode_lock(d_inode(dir));
+retry:
start = jiffies;
subdir = lookup_one_len(dirname, dir, strlen(dirname));
cachefiles_hist(cachefiles_lookup_histogram, start);
@@ -793,6 +799,10 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
if (ret < 0)
goto mkdir_error;
+ if (unlikely(d_unhashed(subdir))) {
+ dput(subdir);
+ goto retry;
+ }
ASSERT(d_backing_inode(subdir));
_debug("mkdir -> %p{%p{ino=%lu}}",