BKL: Remove BKL from ext2 filesystem
Jan Blunck [Wed, 14 Apr 2010 12:38:39 +0000 (14:38 +0200)]
The BKL is still used in ext2_put_super(), ext2_fill_super(), ext2_sync_fs()
ext2_remount() and ext2_write_inode(). From these calls ext2_put_super(),
ext2_fill_super() and ext2_remount() are protected against each other by
the struct super_block s_umount rw semaphore. The call in ext2_write_inode()
could only protect the modification of the ext2_sb_info through
ext2_update_dynamic_rev() against concurrent ext2_sync_fs() or ext2_remount().
ext2_fill_super() and ext2_put_super() can be left out because you need a
valid filesystem reference in all three cases, which you do not have when
you are one of these functions.

If the BKL is only protecting the modification of the ext2_sb_info it can
safely be removed since this is protected by the struct ext2_sb_info s_lock.

Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/inode.c
fs/ext2/super.c

index 5d15442..b90c3bf 100644 (file)
@@ -22,7 +22,6 @@
  *  Assorted race fixes, rewrite of ext2_get_block() by Al Viro, 2000
  */
 
-#include <linux/smp_lock.h>
 #include <linux/time.h>
 #include <linux/highuid.h>
 #include <linux/pagemap.h>
@@ -1406,13 +1405,11 @@ static int __ext2_write_inode(struct inode *inode, int do_sync)
                               /* If this is the first large file
                                * created, add a flag to the superblock.
                                */
-                               lock_kernel();
                                spin_lock(&EXT2_SB(sb)->s_lock);
                                ext2_update_dynamic_rev(sb);
                                EXT2_SET_RO_COMPAT_FEATURE(sb,
                                        EXT2_FEATURE_RO_COMPAT_LARGE_FILE);
                                spin_unlock(&EXT2_SB(sb)->s_lock);
-                               unlock_kernel();
                                ext2_write_super(sb);
                        }
                }
index 28f6560..71e9eb1 100644 (file)
@@ -26,7 +26,6 @@
 #include <linux/random.h>
 #include <linux/buffer_head.h>
 #include <linux/exportfs.h>
-#include <linux/smp_lock.h>
 #include <linux/vfs.h>
 #include <linux/seq_file.h>
 #include <linux/mount.h>
@@ -120,8 +119,6 @@ static void ext2_put_super (struct super_block * sb)
        int i;
        struct ext2_sb_info *sbi = EXT2_SB(sb);
 
-       lock_kernel();
-
        if (sb->s_dirt)
                ext2_write_super(sb);
 
@@ -147,8 +144,6 @@ static void ext2_put_super (struct super_block * sb)
        sb->s_fs_info = NULL;
        kfree(sbi->s_blockgroup_lock);
        kfree(sbi);
-
-       unlock_kernel();
 }
 
 static struct kmem_cache * ext2_inode_cachep;
@@ -1170,7 +1165,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
        struct ext2_sb_info *sbi = EXT2_SB(sb);
        struct ext2_super_block *es = EXT2_SB(sb)->s_es;
 
-       lock_kernel();
        spin_lock(&sbi->s_lock);
        if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) {
                ext2_debug("setting valid to 0\n");
@@ -1178,8 +1172,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
        }
        spin_unlock(&sbi->s_lock);
        ext2_sync_super(sb, es, wait);
-       unlock_kernel();
-
        return 0;
 }
 
@@ -1201,7 +1193,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
        unsigned long old_sb_flags;
        int err;
 
-       lock_kernel();
        spin_lock(&sbi->s_lock);
 
        /* Store the old options */
@@ -1242,14 +1233,12 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
        }
        if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY)) {
                spin_unlock(&sbi->s_lock);
-               unlock_kernel();
                return 0;
        }
        if (*flags & MS_RDONLY) {
                if (le16_to_cpu(es->s_state) & EXT2_VALID_FS ||
                    !(sbi->s_mount_state & EXT2_VALID_FS)) {
                        spin_unlock(&sbi->s_lock);
-                       unlock_kernel();
                        return 0;
                }
                /*
@@ -1282,7 +1271,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
                spin_unlock(&sbi->s_lock);
                ext2_write_super(sb);
        }
-       unlock_kernel();
        return 0;
 restore_opts:
        sbi->s_mount_opt = old_opts.s_mount_opt;
@@ -1290,7 +1278,6 @@ restore_opts:
        sbi->s_resgid = old_opts.s_resgid;
        sb->s_flags = old_sb_flags;
        spin_unlock(&sbi->s_lock);
-       unlock_kernel();
        return err;
 }