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btrfs: tree-check: reduce stack consumption in check_dir_item

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commit e2683fc9d219430f5b78889b50cde7f40efeba7b upstream.

I've noticed that the updated item checker stack consumption increased
dramatically in 542f5385e20cf97447 ("btrfs: tree-checker: Add checker
for dir item")

tree-checker.c:check_leaf                    +552 (176 -> 728)

The array is 255 bytes long, dynamic allocation would slow down the
sanity checks so it's more reasonable to keep it on-stack. Moving the
variable to the scope of use reduces the stack usage again

tree-checker.c:check_leaf                    -264 (728 -> 464)

Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
David Sterba 2018-01-10 15:13:07 +01:00 committed by Greg Kroah-Hartman
parent 6b66f518c5
commit db438c3337
1 changed files with 2 additions and 1 deletions

3
fs/btrfs/tree-checker.c

@ -212,7 +212,6 @@ static int check_dir_item(struct btrfs_root *root,
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
while (cur < item_size) {
char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
u32 name_len;
u32 data_len;
u32 max_name_len;
@ -295,6 +294,8 @@ static int check_dir_item(struct btrfs_root *root,
*/
if (key->type == BTRFS_DIR_ITEM_KEY ||
key->type == BTRFS_XATTR_ITEM_KEY) {
char namebuf[max(BTRFS_NAME_LEN, XATTR_NAME_MAX)];
read_extent_buffer(leaf, namebuf,
(unsigned long)(di + 1), name_len);
name_hash = btrfs_name_hash(namebuf, name_len);