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/affs/super.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'fs/affs') diff --git a/fs/affs/super.c b/fs/affs/super.c index 33c4e7eef470..3a6d1dee4a51 100644 --- a/fs/affs/super.c +++ b/fs/affs/super.c @@ -291,6 +291,8 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent) u8 sig[4]; int ret = -EINVAL; + lock_kernel(); + save_mount_options(sb, data); pr_debug("AFFS: read_super(%s)\n",data ? (const char *)data : "no options"); @@ -300,8 +302,10 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent) sb->s_flags |= MS_NODIRATIME; sbi = kzalloc(sizeof(struct affs_sb_info), GFP_KERNEL); - if (!sbi) + if (!sbi) { + unlock_kernel(); return -ENOMEM; + } sb->s_fs_info = sbi; mutex_init(&sbi->s_bmlock); spin_lock_init(&sbi->symlink_lock); @@ -312,6 +316,7 @@ static int affs_fill_super(struct super_block *sb, void *data, int silent) printk(KERN_ERR "AFFS: Error parsing options\n"); kfree(sbi->s_prefix); kfree(sbi); + unlock_kernel(); return -EINVAL; } /* N.B. after this point s_prefix must be released */ @@ -482,6 +487,7 @@ got_root: sb->s_root->d_op = &affs_dentry_operations; pr_debug("AFFS: s_flags=%lX\n",sb->s_flags); + unlock_kernel(); return 0; /* @@ -496,6 +502,7 @@ out_error_noinode: kfree(sbi->s_prefix); kfree(sbi); sb->s_fs_info = NULL; + unlock_kernel(); return ret; } -- cgit v1.2.3