[3.16.y-ckt stable] Patch "GFS2: Make rename not save dirent location" has been added to staging queue

[Luis Henriques]

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

    GFS2: Make rename not save dirent location

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?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

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 0f6fa8ca249e0474ac5921456a2d2a0bc1fab1d6 Mon Sep 17 00:00:00 2001
From: Bob Peterson <rpeterso at redhat.com>
Date: Mon, 29 Sep 2014 08:52:04 -0400
Subject: GFS2: Make rename not save dirent location

commit 19aeb5a65f1a6504fc665466c188241e7393d66f upstream.

This patch fixes a regression in the patch "GFS2: Remember directory
insert point", commit 2b47dad866d04f14c328f888ba5406057b8c7d33.
The problem had to do with the rename function: The function found
space for the new dirent, and remembered that location. But then the
old dirent was removed, which often moved the eligible location for
the renamed dirent. Putting the new dirent at the saved location
caused file system corruption.

This patch adds a new "save_loc" variable to struct gfs2_diradd.
If 1, the dirent location is saved. If 0, the dirent location is not
saved and the buffer_head is released as per previous behavior.

Signed-off-by: Bob Peterson <rpeterso at redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/gfs2/dir.c   | 9 +++++++--
 fs/gfs2/dir.h   | 1 +
 fs/gfs2/inode.c | 6 +++---
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 1a349f9a9685..5d4261ff5d23 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -2100,8 +2100,13 @@ int gfs2_diradd_alloc_required(struct inode *inode, const struct qstr *name,
 	}
 	if (IS_ERR(dent))
 		return PTR_ERR(dent);
-	da->bh = bh;
-	da->dent = dent;
+
+	if (da->save_loc) {
+		da->bh = bh;
+		da->dent = dent;
+	} else {
+		brelse(bh);
+	}
 	return 0;
 }

diff --git a/fs/gfs2/dir.h b/fs/gfs2/dir.h
index 126c65dda028..e1b309c24dab 100644
--- a/fs/gfs2/dir.h
+++ b/fs/gfs2/dir.h
@@ -23,6 +23,7 @@ struct gfs2_diradd {
 	unsigned nr_blocks;
 	struct gfs2_dirent *dent;
 	struct buffer_head *bh;
+	int save_loc;
 };

 extern struct inode *gfs2_dir_search(struct inode *dir,
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 9c1a680ee468..ba4b2e5377db 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -600,7 +600,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
 	int error, free_vfs_inode = 0;
 	u32 aflags = 0;
 	unsigned blocks = 1;
-	struct gfs2_diradd da = { .bh = NULL, };
+	struct gfs2_diradd da = { .bh = NULL, .save_loc = 1, };

 	if (!name->len || name->len > GFS2_FNAMESIZE)
 		return -ENAMETOOLONG;
@@ -897,7 +897,7 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
 	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder ghs[2];
 	struct buffer_head *dibh;
-	struct gfs2_diradd da = { .bh = NULL, };
+	struct gfs2_diradd da = { .bh = NULL, .save_loc = 1, };
 	int error;

 	if (S_ISDIR(inode->i_mode))
@@ -1335,7 +1335,7 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
 	struct gfs2_rgrpd *nrgd;
 	unsigned int num_gh;
 	int dir_rename = 0;
-	struct gfs2_diradd da = { .nr_blocks = 0, };
+	struct gfs2_diradd da = { .nr_blocks = 0, .save_loc = 0, };
 	unsigned int x;
 	int error;

--
2.1.0