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Date: Mon, 14 Dec 2009 13:00:30 -0600
From: Eric Sandeen <sandeen@...hat.com>
To: ext4 development <linux-ext4@...r.kernel.org>
CC: Jan Kara <jack@...e.cz>, Theodore Tso <tytso@....edu>
Subject: [PATCH 3/4] ext3: Replace lock/unlock_super() with an explicit lock
for the orphan list
From: Theodore Ts'o <tytso@....edu>
Use a separate lock to protect the orphan list, so we can stop
overloading the use of lock_super().
Crossport of 3b9d4ed26680771295d904a6b83e88e620780893
Signed-off-by: Eric Sandeen <sandeen@...hat.com>
---
fs/ext3/namei.c | 20 +++++++++++---------
fs/ext3/super.c | 1 +
include/linux/ext3_fs_sb.h | 1 +
3 files changed, 13 insertions(+), 9 deletions(-)
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index aad6400..76d4c58 100644
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -1920,7 +1920,7 @@ int ext3_orphan_add(handle_t *handle, struct inode *inode)
struct ext3_iloc iloc;
int err = 0, rc;
- lock_super(sb);
+ mutex_lock(&EXT3_SB(sb)->s_orphan_lock);
if (!list_empty(&EXT3_I(inode)->i_orphan))
goto out_unlock;
@@ -1929,9 +1929,13 @@ int ext3_orphan_add(handle_t *handle, struct inode *inode)
/* @@@ FIXME: Observation from aviro:
* I think I can trigger J_ASSERT in ext3_orphan_add(). We block
- * here (on lock_super()), so race with ext3_link() which might bump
+ * here (on s_orphan_lock), so race with ext3_link() which might bump
* ->i_nlink. For, say it, character device. Not a regular file,
* not a directory, not a symlink and ->i_nlink > 0.
+ *
+ * tytso, 4/25/2009: I'm not sure how that could happen;
+ * shouldn't the fs core protect us from these sort of
+ * unlink()/link() races?
*/
J_ASSERT ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
@@ -1968,7 +1972,7 @@ int ext3_orphan_add(handle_t *handle, struct inode *inode)
jbd_debug(4, "orphan inode %lu will point to %d\n",
inode->i_ino, NEXT_ORPHAN(inode));
out_unlock:
- unlock_super(sb);
+ mutex_unlock(&EXT3_SB(sb)->s_orphan_lock);
ext3_std_error(inode->i_sb, err);
return err;
}
@@ -1986,11 +1990,9 @@ int ext3_orphan_del(handle_t *handle, struct inode *inode)
struct ext3_iloc iloc;
int err = 0;
- lock_super(inode->i_sb);
- if (list_empty(&ei->i_orphan)) {
- unlock_super(inode->i_sb);
- return 0;
- }
+ mutex_lock(&EXT3_SB(inode->i_sb)->s_orphan_lock);
+ if (list_empty(&ei->i_orphan))
+ goto out;
ino_next = NEXT_ORPHAN(inode);
prev = ei->i_orphan.prev;
@@ -2040,7 +2042,7 @@ int ext3_orphan_del(handle_t *handle, struct inode *inode)
out_err:
ext3_std_error(inode->i_sb, err);
out:
- unlock_super(inode->i_sb);
+ mutex_unlock(&EXT3_SB(inode->i_sb)->s_orphan_lock);
return err;
out_brelse:
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 602b308..534557c 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1890,6 +1890,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
sb->dq_op = &ext3_quota_operations;
#endif
INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
+ mutex_init(&sbi->s_orphan_lock);
sb->s_root = NULL;
diff --git a/include/linux/ext3_fs_sb.h b/include/linux/ext3_fs_sb.h
index f07f34d..dd61d83 100644
--- a/include/linux/ext3_fs_sb.h
+++ b/include/linux/ext3_fs_sb.h
@@ -72,6 +72,7 @@ struct ext3_sb_info {
struct inode * s_journal_inode;
struct journal_s * s_journal;
struct list_head s_orphan;
+ struct mutex s_orphan_lock;
unsigned long s_commit_interval;
struct block_device *journal_bdev;
#ifdef CONFIG_JBD_DEBUG
-- 1.6.0.6
--
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