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authorNaohiro Aota <naohiro.aota@wdc.com>2019-07-26 16:47:05 +0900
committerDavid Sterba <dsterba@suse.com>2019-07-26 12:21:22 +0200
commita3b46b86ca76d7f9d487e6a0b594fd1984e0796e (patch)
treeefab271e267efffe207b474b9959af63152f683d /fs
parent6e7ca09b583de4be6c27d9d4b06e8c5dd46a58fa (diff)
downloadlinux-a3b46b86ca76d7f9d487e6a0b594fd1984e0796e.tar.bz2
btrfs: fix extent_state leak in btrfs_lock_and_flush_ordered_range
btrfs_lock_and_flush_ordered_range() loads given "*cached_state" into cachedp, which, in general, is NULL. Then, lock_extent_bits() updates "cachedp", but it never goes backs to the caller. Thus the caller still see its "cached_state" to be NULL and never free the state allocated under btrfs_lock_and_flush_ordered_range(). As a result, we will see massive state leak with e.g. fstests btrfs/005. Fix this bug by properly handling the pointers. Fixes: bd80d94efb83 ("btrfs: Always use a cached extent_state in btrfs_lock_and_flush_ordered_range") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ordered-data.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index 1744ba8b2754..ae7f64a8facb 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -985,13 +985,14 @@ void btrfs_lock_and_flush_ordered_range(struct extent_io_tree *tree,
struct extent_state **cached_state)
{
struct btrfs_ordered_extent *ordered;
- struct extent_state *cachedp = NULL;
+ struct extent_state *cache = NULL;
+ struct extent_state **cachedp = &cache;
if (cached_state)
- cachedp = *cached_state;
+ cachedp = cached_state;
while (1) {
- lock_extent_bits(tree, start, end, &cachedp);
+ lock_extent_bits(tree, start, end, cachedp);
ordered = btrfs_lookup_ordered_range(inode, start,
end - start + 1);
if (!ordered) {
@@ -1001,10 +1002,10 @@ void btrfs_lock_and_flush_ordered_range(struct extent_io_tree *tree,
* aren't exposing it outside of this function
*/
if (!cached_state)
- refcount_dec(&cachedp->refs);
+ refcount_dec(&cache->refs);
break;
}
- unlock_extent_cached(tree, start, end, &cachedp);
+ unlock_extent_cached(tree, start, end, cachedp);
btrfs_start_ordered_extent(&inode->vfs_inode, ordered, 1);
btrfs_put_ordered_extent(ordered);
}