BKL: Explicitly add BKL around get_sb/fill_super

This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]

Signed-off-by: Jan Blunck <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Christoph Hellwig <[email protected]>
This commit is contained in:
Jan Blunck 2010-08-15 22:51:10 +02:00 • committed by Arnd Bergmann
commit db71922217
28 changed files with 187 additions and 25 deletions

View file

@ -747,15 +747,18 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
__le32 features;
int err;
lock_kernel();
err = -ENOMEM;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
goto failed_unlock;
sbi->s_blockgroup_lock =
kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
if (!sbi->s_blockgroup_lock) {
kfree(sbi);
return -ENOMEM;
goto failed_unlock;
}
sb->s_fs_info = sbi;
sbi->s_sb_block = sb_block;
@ -1083,6 +1086,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
if (ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY))
sb->s_flags |= MS_RDONLY;
ext2_write_super(sb);
unlock_kernel();
return 0;
cantfind_ext2:
@ -1107,6 +1111,8 @@ failed_sbi:
sb->s_fs_info = NULL;
kfree(sbi->s_blockgroup_lock);
kfree(sbi);
failed_unlock:
unlock_kernel();
return ret;
}