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/ext3/super.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'fs/ext3') diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 5dbf4db..41f9dcd 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -1611,14 +1611,19 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) __le32 features; int err; + lock_kernel(); + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); - if (!sbi) + if (!sbi) { + unlock_kernel(); return -ENOMEM; + } sbi->s_blockgroup_lock = kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL); if (!sbi->s_blockgroup_lock) { kfree(sbi); + unlock_kernel(); return -ENOMEM; } sb->s_fs_info = sbi; @@ -2026,6 +2031,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) "writeback"); lock_kernel(); + unlock_kernel(); return 0; cantfind_ext3: @@ -2056,6 +2062,7 @@ out_fail: kfree(sbi->s_blockgroup_lock); kfree(sbi); lock_kernel(); + unlock_kernel(); return ret; } -- cgit v1.1 From d646cf82e9b6a58ba2d748e66e5fc7223830c68c Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Wed, 24 Feb 2010 13:25:29 +0100 Subject: BKL: Remove BKL from ext3 fill_super() The BKL is protecting nothing than two memory allocations here. Signed-off-by: Jan Blunck Acked-by: Jan Kara Signed-off-by: Arnd Bergmann --- fs/ext3/super.c | 13 +------------ 1 file changed, 1 insertion(+), 12 deletions(-) (limited to 'fs/ext3') diff --git a/fs/ext3/super.c b/fs/ext3/super.c index 41f9dcd..edde63f 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -1611,19 +1611,14 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) __le32 features; int err; - lock_kernel(); - sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); - if (!sbi) { - unlock_kernel(); + if (!sbi) return -ENOMEM; - } sbi->s_blockgroup_lock = kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL); if (!sbi->s_blockgroup_lock) { kfree(sbi); - unlock_kernel(); return -ENOMEM; } sb->s_fs_info = sbi; @@ -1632,8 +1627,6 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) sbi->s_resgid = EXT3_DEF_RESGID; sbi->s_sb_block = sb_block; - unlock_kernel(); - blocksize = sb_min_blocksize(sb, EXT3_MIN_BLOCK_SIZE); if (!blocksize) { ext3_msg(sb, KERN_ERR, "error: unable to set blocksize"); @@ -2030,8 +2023,6 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA ? "ordered": "writeback"); - lock_kernel(); - unlock_kernel(); return 0; cantfind_ext3: @@ -2061,8 +2052,6 @@ out_fail: sb->s_fs_info = NULL; kfree(sbi->s_blockgroup_lock); kfree(sbi); - lock_kernel(); - unlock_kernel(); return ret; } -- cgit v1.1 From 77b54a46a83232d172d55013c3af838190615260 Mon Sep 17 00:00:00 2001 From: Jan Blunck Date: Wed, 24 Feb 2010 13:25:30 +0100 Subject: BKL: Remove BKL from ext3_put_super() and ext3_remount() The BKL lock is protecting the remounting against a potential call to ext3_put_super(). This could not happen, since this is protected by the s_umount rw semaphore of struct super_block. Therefore I think the BKL is protecting nothing here. Signed-off-by: Jan Blunck Acked-by: Jan Kara Signed-off-by: Arnd Bergmann --- fs/ext3/super.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'fs/ext3') diff --git a/fs/ext3/super.c b/fs/ext3/super.c index edde63f..2e20bd7 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -411,9 +411,6 @@ static void ext3_put_super (struct super_block * sb) int i, err; dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED); - - lock_kernel(); - ext3_xattr_put_super(sb); err = journal_destroy(sbi->s_journal); sbi->s_journal = NULL; @@ -462,8 +459,6 @@ static void ext3_put_super (struct super_block * sb) sb->s_fs_info = NULL; kfree(sbi->s_blockgroup_lock); kfree(sbi); - - unlock_kernel(); } static struct kmem_cache *ext3_inode_cachep; @@ -2534,8 +2529,6 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data) int i; #endif - lock_kernel(); - /* Store the original options */ lock_super(sb); old_sb_flags = sb->s_flags; @@ -2644,7 +2637,6 @@ static int ext3_remount (struct super_block * sb, int * flags, char * data) kfree(old_opts.s_qf_names[i]); #endif unlock_super(sb); - unlock_kernel(); if (enable_quota) dquot_resume(sb, -1); @@ -2665,7 +2657,6 @@ restore_opts: } #endif unlock_super(sb); - unlock_kernel(); return err; } -- cgit v1.1