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    Subject[PATCH 20/20] BKL: Remove BKL from ext2 filesystem
    Date
    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>
    ---
    fs/ext2/inode.c | 3 ---
    fs/ext2/super.c | 16 ----------------
    2 files changed, 0 insertions(+), 19 deletions(-)

    diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
    index 65a0d4b..5afb161 100644
    --- a/fs/ext2/inode.c
    +++ b/fs/ext2/inode.c
    @@ -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>
    @@ -1400,13 +1399,11 @@ 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);
    }
    }
    diff --git a/fs/ext2/super.c b/fs/ext2/super.c
    index 0ca42fe..a764002 100644
    --- a/fs/ext2/super.c
    +++ b/fs/ext2/super.c
    @@ -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 && !(sb->s_flags & MS_RDONLY))
    ext2_sync_fs(sb, 1);

    @@ -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;
    @@ -754,8 +749,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
    __le32 features;
    int err;

    - lock_kernel();
    -
    err = -ENOMEM;
    sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
    if (!sbi)
    @@ -1081,7 +1074,6 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
    ext2_warning(sb, __func__,
    "mounting ext3 filesystem as ext2");
    ext2_setup_super (sb, es, sb->s_flags & MS_RDONLY);
    - unlock_kernel();
    return 0;

    cantfind_ext2:
    @@ -1106,7 +1098,6 @@ failed_sbi:
    kfree(sbi->s_blockgroup_lock);
    kfree(sbi);
    failed_unlock:
    - unlock_kernel();
    return ret;
    }

    @@ -1149,7 +1140,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
    struct ext2_sb_info *sbi = EXT2_SB(sb);
    struct ext2_super_block *es = sbi->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");
    @@ -1166,7 +1156,6 @@ static int ext2_sync_fs(struct super_block *sb, int wait)
    spin_unlock(&sbi->s_lock);
    }
    sb->s_dirt = 0;
    - unlock_kernel();

    return 0;
    }
    @@ -1189,7 +1178,6 @@ 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 */
    @@ -1229,14 +1217,12 @@ 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;
    }
    /*
    @@ -1266,7 +1252,6 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
    }
    spin_unlock(&EXT2_SB(sb)->s_lock);
    ext2_sync_super(sb, es);
    - unlock_kernel();
    return 0;
    restore_opts:
    sbi->s_mount_opt = old_opts.s_mount_opt;
    @@ -1274,7 +1259,6 @@ restore_opts:
    sbi->s_resgid = old_opts.s_resgid;
    sb->s_flags = old_sb_flags;
    spin_unlock(&sbi->s_lock);
    - unlock_kernel();
    return err;
    }

    --
    1.6.4.2


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