From a3b46b86ca76d7f9d487e6a0b594fd1984e0796e Mon Sep 17 00:00:00 2001 From: Naohiro Aota Date: Fri, 26 Jul 2019 16:47:05 +0900 Subject: [PATCH] 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 Signed-off-by: Naohiro Aota Signed-off-by: David Sterba --- fs/btrfs/ordered-data.c | 11 ++++++----- 1 file 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); } -- 2.30.2