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Commit 3b9d4ed2 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: Replace lock/unlock_super() with an explicit lock for the orphan list 



Use a separate lock to protect the orphan list, so we can stop
overloading the use of lock_super().

Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent a63c9eb2

fs/ext4/ext4_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct ext4_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;

	u32 s_max_batch_time;

	u32 s_min_batch_time;

fs/ext4/namei.c

+11 −9
Original line number Diff line number Diff line
@@ -1997,7 +1997,7 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode) 
	if (!ext4_handle_valid(handle))

		return 0;



	lock_super(sb);

	mutex_lock(&EXT4_SB(sb)->s_orphan_lock);

	if (!list_empty(&EXT4_I(inode)->i_orphan))

		goto out_unlock;
@@ -2006,9 +2006,13 @@ int ext4_orphan_add(handle_t *handle, struct inode *inode) 


	/* @@@ FIXME: Observation from aviro:

	 * I think I can trigger J_ASSERT in ext4_orphan_add().  We block

	 * here (on lock_super()), so race with ext4_link() which might bump

	 * here (on s_orphan_lock), so race with ext4_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);
@@ -2045,7 +2049,7 @@ int ext4_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(&EXT4_SB(sb)->s_orphan_lock);

	ext4_std_error(inode->i_sb, err);

	return err;

}
@@ -2066,11 +2070,9 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode) 
	if (!ext4_handle_valid(handle))

		return 0;



	lock_super(inode->i_sb);

	if (list_empty(&ei->i_orphan)) {

		unlock_super(inode->i_sb);

		return 0;

	}

	mutex_lock(&EXT4_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;
@@ -2120,7 +2122,7 @@ int ext4_orphan_del(handle_t *handle, struct inode *inode) 
out_err:

	ext4_std_error(inode->i_sb, err);

out:

	unlock_super(inode->i_sb);

	mutex_unlock(&EXT4_SB(inode->i_sb)->s_orphan_lock);

	return err;



out_brelse:

fs/ext4/super.c

+1 −0
Original line number Diff line number Diff line
@@ -2645,6 +2645,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) 
	sb->dq_op = &ext4_quota_operations;

#endif

	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */

	mutex_init(&sbi->s_orphan_lock);



	sb->s_root = NULL;