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/freevxfs/vxfs_super.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'fs/freevxfs/vxfs_super.c') diff --git a/fs/freevxfs/vxfs_super.c b/fs/freevxfs/vxfs_super.c index dc0c041e85cb..eb2b9e09c996 100644 --- a/fs/freevxfs/vxfs_super.c +++ b/fs/freevxfs/vxfs_super.c @@ -148,7 +148,7 @@ static int vxfs_remount(struct super_block *sb, int *flags, char *data) * The superblock on success, else %NULL. * * Locking: - * We are under the bkl and @sbp->s_lock. + * We are under @sbp->s_lock. */ static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent) { @@ -159,11 +159,14 @@ static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent) struct inode *root; int ret = -EINVAL; + lock_kernel(); + sbp->s_flags |= MS_RDONLY; infp = kzalloc(sizeof(*infp), GFP_KERNEL); if (!infp) { printk(KERN_WARNING "vxfs: unable to allocate incore superblock\n"); + unlock_kernel(); return -ENOMEM; } @@ -236,6 +239,7 @@ static int vxfs_fill_super(struct super_block *sbp, void *dp, int silent) goto out_free_ilist; } + unlock_kernel(); return 0; out_free_ilist: @@ -245,6 +249,7 @@ out_free_ilist: out: brelse(bp); kfree(infp); + unlock_kernel(); return ret; } -- cgit v1.2.3