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/ext2/super.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'fs/ext2/super.c') diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 1ec602673ea..f98c390caf1 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -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; } -- cgit v1.2.3