2009-11-02 10:04:48

by Jan Blunck

[permalink] [raw]
Subject: [PATCH 08/27] BKL: Remove BKL from ext4 filesystem

The BKL is still used in ext4_put_super(), ext4_fill_super() and
ext4_remount(). All three calles are protected against concurrent calls by
the s_umount rw semaphore of struct super_block.

Therefore the BKL is protecting nothing in this case.

Signed-off-by: Jan Blunck <[email protected]>
---
fs/ext4/super.c | 16 +---------------
1 files changed, 1 insertions(+), 15 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9db81d2..328e9dc 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -26,7 +26,6 @@
#include <linux/init.h>
#include <linux/blkdev.h>
#include <linux/parser.h>
-#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/exportfs.h>
#include <linux/vfs.h>
@@ -599,7 +598,6 @@ static void ext4_put_super(struct super_block *sb)
destroy_workqueue(sbi->dio_unwritten_wq);

lock_super(sb);
- lock_kernel();
if (sb->s_dirt)
ext4_commit_super(sb, 1);

@@ -665,7 +663,6 @@ static void ext4_put_super(struct super_block *sb)
* Now that we are completely done shutting down the
* superblock, we need to actually destroy the kobject.
*/
- unlock_kernel();
unlock_super(sb);
kobject_put(&sbi->s_kobj);
wait_for_completion(&sbi->s_kobj_unregister);
@@ -2328,19 +2325,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
int err;
unsigned int journal_ioprio = DEFAULT_JOURNAL_IOPRIO;

- lock_kernel();
-
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
- if (!sbi) {
- unlock_kernel();
+ if (!sbi)
return -ENOMEM;
- }

sbi->s_blockgroup_lock =
kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
if (!sbi->s_blockgroup_lock) {
kfree(sbi);
- unlock_kernel();
return -ENOMEM;
}
sb->s_fs_info = sbi;
@@ -2352,8 +2344,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
sbi->s_sectors_written_start = part_stat_read(sb->s_bdev->bd_part,
sectors[1]);

- unlock_kernel();
-
/* Cleanup superblock name */
for (cp = sb->s_id; (cp = strchr(cp, '/'));)
*cp = '!';
@@ -3456,8 +3446,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
int i;
#endif

- lock_kernel();
-
/* Store the original options */
lock_super(sb);
old_sb_flags = sb->s_flags;
@@ -3587,7 +3575,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
kfree(old_opts.s_qf_names[i]);
#endif
unlock_super(sb);
- unlock_kernel();
return 0;

restore_opts:
@@ -3608,7 +3595,6 @@ restore_opts:
}
#endif
unlock_super(sb);
- unlock_kernel();
return err;
}

--
1.6.4.2



2009-11-09 14:45:05

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH 08/27] BKL: Remove BKL from ext4 filesystem

On Mon, Nov 02, 2009 at 11:04:48AM +0100, Jan Blunck wrote:
> The BKL is still used in ext4_put_super(), ext4_fill_super() and
> ext4_remount(). All three calles are protected against concurrent calls by
> the s_umount rw semaphore of struct super_block.
>
> Therefore the BKL is protecting nothing in this case.
>
> Signed-off-by: Jan Blunck <[email protected]>

Acked-by: "Theodore Ts'o" <[email protected]>

- Ted