lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

BKL: Explicitly add BKL around get_sb/fill_super

Browse Source 
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 <jblunck@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Christoph Hellwig <hch@infradead.org>
This commit is contained in:
Jan Blunck
2010-08-15 22:51:10 +02:00
committed by Arnd Bergmann
parent 899611ee7d
commit db71922217
28 changed files with 187 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
fs/squashfs/super.c
View File

@ -87,11 +87,14 @@ static int squashfs_fill_super(struct super_block *sb, void *data, int silent)
u64 lookup_table_start, xattr_id_table_start;
int err;
lock_kernel();
TRACE("Entered squashfs_fill_superblock\n");
sb->s_fs_info = kzalloc(sizeof(*msblk), GFP_KERNEL);
if (sb->s_fs_info == NULL) {
ERROR("Failed to allocate squashfs_sb_info\n");
unlock_kernel();
return -ENOMEM;
}
msblk = sb->s_fs_info;
@ -301,6 +304,7 @@ allocate_root:
TRACE("Leaving squashfs_fill_super\n");
kfree(sblk);
unlock_kernel();
return 0;
failed_mount:
@ -315,11 +319,13 @@ failed_mount:
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
kfree(sblk);
unlock_kernel();
return err;
failure:
kfree(sb->s_fs_info);
sb->s_fs_info = NULL;
unlock_kernel();
return -ENOMEM;
}