Patch "UBIFS: make space fixup work in the remount case" has been added to the 3.4-stable tree

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This is a note to let you know that I've just added the patch titled

    UBIFS: make space fixup work in the remount case

to the 3.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ubifs-make-space-fixup-work-in-the-remount-case.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 67e753ca41782913d805ff4a8a2b0f60b26b7915 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Date: Thu, 14 Mar 2013 10:49:23 +0200
Subject: UBIFS: make space fixup work in the remount case

From: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>

commit 67e753ca41782913d805ff4a8a2b0f60b26b7915 upstream.

The UBIFS space fixup is a useful feature which allows to fixup the "broken"
flash space at the time of the first mount. The "broken" space is usually the
result of using a "dumb" industrial flasher which is not able to skip empty
NAND pages and just writes all 0xFFs to the empty space, which has grave
side-effects for UBIFS when UBIFS trise to write useful data to those empty
pages.

The fix-up feature works roughly like this:
1. mkfs.ubifs sets the fixup flag in UBIFS superblock when creating the image
   (see -F option)
2. when the file-system is mounted for the first time, UBIFS notices the fixup
   flag and re-writes the entire media atomically, which may take really a lot
   of time.
3. UBIFS clears the fixup flag in the superblock.

This works fine when the file system is mounted R/W for the very first time.
But it did not really work in the case when we first mount the file-system R/O,
and then re-mount R/W. The reason was that we started the fixup procedure too
late, which we cannot really do because we have to fixup the space before it
starts being used.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx>
Reported-by: Mark Jackson <mpfj-list@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 fs/ubifs/super.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1582,6 +1582,12 @@ static int ubifs_remount_rw(struct ubifs
 	c->remounting_rw = 1;
 	c->ro_mount = 0;
 
+	if (c->space_fixup) {
+		err = ubifs_fixup_free_space(c);
+		if (err)
+			return err;
+	}
+
 	err = check_free_space(c);
 	if (err)
 		goto out;
@@ -1698,12 +1704,6 @@ static int ubifs_remount_rw(struct ubifs
 		err = dbg_check_space_info(c);
 	}
 
-	if (c->space_fixup) {
-		err = ubifs_fixup_free_space(c);
-		if (err)
-			goto out;
-	}
-
 	mutex_unlock(&c->umount_mutex);
 	return err;
 


Patches currently in stable-queue which might be from artem.bityutskiy@xxxxxxxxxxxxxxx are

queue-3.4/ubifs-make-space-fixup-work-in-the-remount-case.patch
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