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| author | Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2011-04-20 06:44:57 (GMT) |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2011-05-23 17:24:41 (GMT) |
| commit | 8233767a227ac5843f1023b88c7272a7b5058f5f (patch) | |
| tree | e37bb379b90d9754035021ad042de1970a5106fc | |
| parent | b083916638eee513be501f53b42a4be0b9851db0 (diff) | |
| download | linux-8233767a227ac5843f1023b88c7272a7b5058f5f.tar.xz | |
Btrfs: allocate extent state and check the result properly
It doesn't allocate extent_state and check the result properly:
- in set_extent_bit, it doesn't allocate extent_state if the path is not
allowed wait
- in clear_extent_bit, it doesn't check the result after atomic-ly allocate,
we trigger BUG_ON() if it's fail
- if allocate fail, we trigger BUG_ON instead of returning -ENOMEM since
the return value of clear_extent_bit() is ignored by many callers
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
| -rw-r--r-- | fs/btrfs/extent_io.c | 34 |
1 files changed, 26 insertions, 8 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index ba41da5..9ccea86 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -439,6 +439,15 @@ static int clear_state_bit(struct extent_io_tree *tree, return ret; } +static struct extent_state * +alloc_extent_state_atomic(struct extent_state *prealloc) +{ + if (!prealloc) + prealloc = alloc_extent_state(GFP_ATOMIC); + + return prealloc; +} + /* * clear some bits on a range in the tree. This may require splitting * or inserting elements in the tree, so the gfp mask is used to @@ -476,8 +485,7 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, again: if (!prealloc && (mask & __GFP_WAIT)) { prealloc = alloc_extent_state(mask); - if (!prealloc) - return -ENOMEM; + BUG_ON(!prealloc); } spin_lock(&tree->lock); @@ -529,8 +537,8 @@ hit_next: */ if (state->start < start) { - if (!prealloc) - prealloc = alloc_extent_state(GFP_ATOMIC); + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = split_state(tree, state, prealloc, start); BUG_ON(err == -EEXIST); prealloc = NULL; @@ -551,8 +559,8 @@ hit_next: * on the first half */ if (state->start <= end && state->end > end) { - if (!prealloc) - prealloc = alloc_extent_state(GFP_ATOMIC); + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = split_state(tree, state, prealloc, end + 1); BUG_ON(err == -EEXIST); if (wake) @@ -725,8 +733,7 @@ int set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, again: if (!prealloc && (mask & __GFP_WAIT)) { prealloc = alloc_extent_state(mask); - if (!prealloc) - return -ENOMEM; + BUG_ON(!prealloc); } spin_lock(&tree->lock); @@ -743,6 +750,8 @@ again: */ node = tree_search(tree, start); if (!node) { + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = insert_state(tree, prealloc, start, end, &bits); prealloc = NULL; BUG_ON(err == -EEXIST); @@ -811,6 +820,9 @@ hit_next: err = -EEXIST; goto out; } + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = split_state(tree, state, prealloc, start); BUG_ON(err == -EEXIST); prealloc = NULL; @@ -841,6 +853,9 @@ hit_next: this_end = end; else this_end = last_start - 1; + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = insert_state(tree, prealloc, start, this_end, &bits); BUG_ON(err == -EEXIST); @@ -865,6 +880,9 @@ hit_next: err = -EEXIST; goto out; } + + prealloc = alloc_extent_state_atomic(prealloc); + BUG_ON(!prealloc); err = split_state(tree, state, prealloc, end + 1); BUG_ON(err == -EEXIST); |