[GIT PULL] logfs: bug fixes

[Artem Bityutskiy]

From: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
Date: Wed, 1 Feb 2012 11:50:07 +0200
Subject: [PATCH] mtd: fix merge conflict resolution breakage

This patch fixes merge conflict resolution breakage introduced by merge
commit 'd3712b9dfcf44ca145cf87e7f4096fa2d923471a'.

The commit changed 'mtd_can_have_bb()' function and made it always return
zero, which is incorrect. Instead, we need it to return whether the
underlying flash device can have bad eraseblocks or not. UBI needs this
information because it affects how it handles the underlying flash.
E.g., if the underlying flash is NOR, it cannot have bad blocks and any
write or erase error is fatal, and all we can do is to switch to R/O
mode. We do not need to reserve a pool of good eraseblocks for bad
eraseblocks handling, and so on.

This patch also removes 'mtd_can_have_bb()' invocations from Logfs
to ensure correct Logfs behavior.

I've tested that with this patch UBI works on top of NOR and NAND
flashes emulated by mtdram and nandsim correspondingly.

This patch is based on patch from Linus Torvalds.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy at linux.intel.com>
---

Linus, here is the emergency fix - basically your patch tested and
and slightly modified. You should probably put yourself as the author.

Also attached the patch for your convenience.

 fs/logfs/dev_mtd.c      |    6 ------
 include/linux/mtd/mtd.h |    2 +-
 2 files changed, 1 insertions(+), 7 deletions(-)

diff --git a/fs/logfs/dev_mtd.c b/fs/logfs/dev_mtd.c
index e97404d..9c50144 100644
--- a/fs/logfs/dev_mtd.c
+++ b/fs/logfs/dev_mtd.c
@@ -152,9 +152,6 @@ static struct page *logfs_mtd_find_first_sb(struct super_block *sb, u64 *ofs)
 	filler_t *filler = logfs_mtd_readpage;
 	struct mtd_info *mtd = super->s_mtd;
 
-	if (!mtd_can_have_bb(mtd))
-		return NULL;
-
 	*ofs = 0;
 	while (mtd_block_isbad(mtd, *ofs)) {
 		*ofs += mtd->erasesize;
@@ -172,9 +169,6 @@ static struct page *logfs_mtd_find_last_sb(struct super_block *sb, u64 *ofs)
 	filler_t *filler = logfs_mtd_readpage;
 	struct mtd_info *mtd = super->s_mtd;
 
-	if (!mtd_can_have_bb(mtd))
-		return NULL;
-
 	*ofs = mtd->size - mtd->erasesize;
 	while (mtd_block_isbad(mtd, *ofs)) {
 		*ofs -= mtd->erasesize;
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index c09020a..d43dc25 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -487,7 +487,7 @@ static inline int mtd_has_oob(const struct mtd_info *mtd)
 
 static inline int mtd_can_have_bb(const struct mtd_info *mtd)
 {
-	return 0;
+	return !!mtd->block_isbad;
 }
 
 	/* Kernel-side ioctl definitions */
-- 
1.7.9
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