From db71922217a214e5c9268448e537b54fc1f301ea Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Sun, 15 Aug 2010 22:51:10 +0200 Subject: 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 Signed-off-by: Arnd Bergmann Cc: Matthew Wilcox Cc: Christoph Hellwig --- fs/nilfs2/super.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'fs/nilfs2') diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c index 922263393c76..0d573c2a6860 100644 --- a/fs/nilfs2/super.c +++ b/fs/nilfs2/super.c @@ -1113,9 +1113,12 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, if (!(flags & MS_RDONLY)) mode |= FMODE_WRITE; + lock_kernel(); sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type); - if (IS_ERR(sd.bdev)) + if (IS_ERR(sd.bdev)) { + unlock_kernel(); return PTR_ERR(sd.bdev); + } /* * To get mount instance using sget() vfs-routine, NILFS needs @@ -1198,6 +1201,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, if (need_to_close) close_bdev_exclusive(sd.bdev, mode); simple_set_mnt(mnt, s); + unlock_kernel(); return 0; failed_unlock: @@ -1206,6 +1210,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, failed: close_bdev_exclusive(sd.bdev, mode); + unlock_kernel(); return err; cancel_new: @@ -1218,6 +1223,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, * We must finish all post-cleaning before this call; * put_nilfs() needs the block device. */ + unlock_kernel(); return err; } -- cgit v1.2.3-59-g8ed1b