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 <jblunck@infradead.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Christoph Hellwig <hch@infradead.org>
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index 6fcc7e7..9006ad9 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -21,6 +21,7 @@
#include <linux/slab.h>
#include <linux/buffer_head.h>
#include <linux/namei.h>
+#include <linux/smp_lock.h> /* For lock_kernel() */
#include "fat.h"
/*
@@ -1055,15 +1056,19 @@
{
int res;
+ lock_kernel();
res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
- if (res)
+ if (res) {
+ unlock_kernel();
return res;
+ }
if (MSDOS_SB(sb)->options.name_check != 's')
sb->s_root->d_op = &vfat_ci_dentry_ops;
else
sb->s_root->d_op = &vfat_dentry_ops;
+ unlock_kernel();
return 0;
}