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/cifs/cifsfs.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'fs/cifs') diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index b7431afdd76..070bf1aecd2 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -514,22 +514,30 @@ cifs_get_sb(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, struct vfsmount *mnt) { int rc; - struct super_block *sb = sget(fs_type, NULL, set_anon_super, NULL); + struct super_block *sb; + + lock_kernel(); + + sb = sget(fs_type, NULL, set_anon_super, NULL); cFYI(1, "Devname: %s flags: %d ", dev_name, flags); - if (IS_ERR(sb)) + if (IS_ERR(sb)) { + unlock_kernel(); return PTR_ERR(sb); + } sb->s_flags = flags; rc = cifs_read_super(sb, data, dev_name, flags & MS_SILENT ? 1 : 0); if (rc) { deactivate_locked_super(sb); + unlock_kernel(); return rc; } sb->s_flags |= MS_ACTIVE; simple_set_mnt(mnt, sb); + unlock_kernel(); return 0; } -- cgit v1.2.3