diff mbox series

btrfs: remove unnecessary NULL check for the new inode during rename exchange

Message ID 8dd8e8f3020a5bd13ae22a1f21b8328adc1f4636.1627568438.git.fdmanana@suse.com (mailing list archive)
State New, archived
Headers show
Series btrfs: remove unnecessary NULL check for the new inode during rename exchange | expand

Commit Message

Filipe Manana July 29, 2021, 2:28 p.m. UTC 
From: Filipe Manana <fdmanana@suse.com>

At the very end of btrfs_rename_exchange(), in case an error happened, we
are checking if 'new_inode' is NULL, but that is not needed since during a
rename exchange, unlike regular renames, 'new_inode' can never be NULL,
and if it were, we would have a crash much earlier when we dereference it
multiple times.

So remove the check because it is not necessary and because it is causing
static checkers to emit a warning. I probably introduced the check by
copy-pasting similar code from btrfs_rename(), where 'new_inode' can be
NULL, in commit 86e8aa0e772cab ("Btrfs: unpin logs if rename exchange
operation fails").

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
 fs/btrfs/inode.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

David Sterba July 29, 2021, 5:27 p.m. UTC | #1 
On Thu, Jul 29, 2021 at 03:28:34PM +0100, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
> 
> At the very end of btrfs_rename_exchange(), in case an error happened, we
> are checking if 'new_inode' is NULL, but that is not needed since during a
> rename exchange, unlike regular renames, 'new_inode' can never be NULL,
> and if it were, we would have a crash much earlier when we dereference it
> multiple times.
> 
> So remove the check because it is not necessary and because it is causing
> static checkers to emit a warning. I probably introduced the check by
> copy-pasting similar code from btrfs_rename(), where 'new_inode' can be
> NULL, in commit 86e8aa0e772cab ("Btrfs: unpin logs if rename exchange
> operation fails").
> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Added to misc-next, thanks.
diff mbox series

Patch

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 59b35e12bb81..ef76bde10913 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9421,8 +9421,7 @@  static int btrfs_rename_exchange(struct inode *old_dir,
 		if (btrfs_inode_in_log(BTRFS_I(old_dir), fs_info->generation) ||
 		    btrfs_inode_in_log(BTRFS_I(new_dir), fs_info->generation) ||
 		    btrfs_inode_in_log(BTRFS_I(old_inode), fs_info->generation) ||
-		    (new_inode &&
-		     btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation)))
+		    btrfs_inode_in_log(BTRFS_I(new_inode), fs_info->generation))
 			btrfs_set_log_full_commit(trans);
 
 		if (root_log_pinned) {