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/squashfs/super.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/squashfs') diff --git a/fs/squashfs/super.c b/fs/squashfs/super.c index 88b4f8606652..ab1a401a0e19 100644 --- a/fs/squashfs/super.c +++ b/fs/squashfs/super.c @@ -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; } -- cgit v1.2.1