[3.16.y-ckt stable] Patch "fs/ufs: revert "ufs: fix deadlocks introduced by sb mutex merge"" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    fs/ufs: revert "ufs: fix deadlocks introduced by sb mutex merge"

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From b3f238c0128d760e1ffc28cf512b6af5e653793a Mon Sep 17 00:00:00 2001
From: Fabian Frederick <fabf at skynet.be>
Date: Wed, 10 Jun 2015 10:09:32 +1000
Subject: fs/ufs: revert "ufs: fix deadlocks introduced by sb mutex merge"

commit 13b987ea275840d74d9df9a44326632fab1894da upstream.

This reverts commit 9ef7db7f38d0 ("ufs: fix deadlocks introduced by sb
mutex merge") That patch tried to solve commit 0244756edc4b98c ("ufs: sb
mutex merge + mutex_destroy") which is itself partially reverted due to
multiple deadlocks.

Signed-off-by: Fabian Frederick <fabf at skynet.be>
Suggested-by: Jan Kara <jack at suse.cz>
Cc: Ian Campbell <ian.campbell at citrix.com>
Cc: Evgeniy Dushistov <dushistov at mail.ru>
Cc: Alexey Khoroshilov <khoroshilov at ispras.ru>
Cc: Roger Pau Monne <roger.pau at citrix.com>
Cc: Ian Jackson <Ian.Jackson at eu.citrix.com>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/ufs/inode.c |  5 ++++-
 fs/ufs/namei.c | 14 ++++++++------
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
index 42234a871b22..40d6423429cb 100644
--- a/fs/ufs/inode.c
+++ b/fs/ufs/inode.c
@@ -902,6 +902,9 @@ void ufs_evict_inode(struct inode * inode)
 	invalidate_inode_buffers(inode);
 	clear_inode(inode);

-	if (want_delete)
+	if (want_delete) {
+		lock_ufs(inode->i_sb);
 		ufs_free_inode(inode);
+		unlock_ufs(inode->i_sb);
+	}
 }
diff --git a/fs/ufs/namei.c b/fs/ufs/namei.c
index 2df62a73f20c..90d74b8f8eba 100644
--- a/fs/ufs/namei.c
+++ b/fs/ufs/namei.c
@@ -126,12 +126,12 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > sb->s_blocksize)
 		goto out_notlocked;

+	lock_ufs(dir->i_sb);
 	inode = ufs_new_inode(dir, S_IFLNK | S_IRWXUGO);
 	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
-		goto out_notlocked;
+		goto out;

-	lock_ufs(dir->i_sb);
 	if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 		/* slow symlink */
 		inode->i_op = &ufs_symlink_inode_operations;
@@ -181,9 +181,13 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
 	struct inode * inode;
 	int err;

+	lock_ufs(dir->i_sb);
+	inode_inc_link_count(dir);
+
 	inode = ufs_new_inode(dir, S_IFDIR|mode);
+	err = PTR_ERR(inode);
 	if (IS_ERR(inode))
-		return PTR_ERR(inode);
+		goto out_dir;

 	inode->i_op = &ufs_dir_inode_operations;
 	inode->i_fop = &ufs_dir_operations;
@@ -191,9 +195,6 @@ static int ufs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)

 	inode_inc_link_count(inode);

-	lock_ufs(dir->i_sb);
-	inode_inc_link_count(dir);
-
 	err = ufs_make_empty(inode, dir);
 	if (err)
 		goto out_fail;
@@ -211,6 +212,7 @@ out_fail:
 	inode_dec_link_count(inode);
 	inode_dec_link_count(inode);
 	iput (inode);
+out_dir:
 	inode_dec_link_count(dir);
 	unlock_ufs(dir->i_sb);
 	goto out;