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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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