Patchwork [3.5.y.z,extended,stable] Patch "UBIFS: make space fixup work in the remount case" has been added to staging queue

login
register
mail settings
Submitter Luis Henriques
Date April 5, 2013, 5:22 p.m.
Message ID <1365182526-30240-1-git-send-email-luis.henriques@canonical.com>
Download mbox | patch
Permalink /patch/234222/
State New
Headers show

Comments

Luis Henriques - April 5, 2013, 5:22 p.m.
This is a note to let you know that I have just added a patch titled

    UBIFS: make space fixup work in the remount case

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

From 39467565a02cb91c1f9bb41d65947267a5228035 Mon Sep 17 00:00:00 2001
From: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Date: Thu, 14 Mar 2013 10:49:23 +0200
Subject: [PATCH] UBIFS: make space fixup work in the remount case

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@linux.intel.com>
Reported-by: Mark Jackson <mpfj-list@mimc.co.uk>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
 fs/ubifs/super.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--
1.8.1.2

Patch

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 5862dd9..202c0e4 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1579,6 +1579,12 @@  static int ubifs_remount_rw(struct ubifs_info *c)
 	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;
@@ -1695,12 +1701,6 @@  static int ubifs_remount_rw(struct ubifs_info *c)
 		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;