This is a note to let you know that I've just added the patch titled
erofs: shouldn't churn the mapping page for duplicated copies
to the 6.0-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:
erofs-shouldn-t-churn-the-mapping-page-for-duplicate.patch
and it can be found in the queue-6.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 04fef1dfae2602495fe640c370da97625329572d
Author: Gao Xiang <xiang@xxxxxxxxxx>
Date: Wed Oct 12 12:50:56 2022 +0800
erofs: shouldn't churn the mapping page for duplicated copies
[ Upstream commit 63bbb85658ea43dd35dbfde6d4150b47c407fc87 ]
If other duplicated copies exist in one decompression shot, should
leave the old page as is rather than replace it with the new duplicated
one. Otherwise, the following cold path to deal with duplicated copies
will use the invalid bvec. It impacts compressed data deduplication.
Also, shift the onlinepage EIO bit to avoid touching the signed bit.
Fixes: 267f2492c8f7 ("erofs: introduce multi-reference pclusters (fully-referenced)")
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221012045056.13421-1-hsiangkao@xxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index 5792ca9e0d5e..6e663275aeb1 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -838,15 +838,13 @@ static void z_erofs_do_decompressed_bvec(struct z_erofs_decompress_backend *be,
if (!((bvec->offset + be->pcl->pageofs_out) & ~PAGE_MASK)) {
unsigned int pgnr;
- struct page *oldpage;
pgnr = (bvec->offset + be->pcl->pageofs_out) >> PAGE_SHIFT;
DBG_BUGON(pgnr >= be->nr_pages);
- oldpage = be->decompressed_pages[pgnr];
- be->decompressed_pages[pgnr] = bvec->page;
-
- if (!oldpage)
+ if (!be->decompressed_pages[pgnr]) {
+ be->decompressed_pages[pgnr] = bvec->page;
return;
+ }
}
/* (cold path) one pcluster is requested multiple times */
diff --git a/fs/erofs/zdata.h b/fs/erofs/zdata.h
index e7f04c4fbb81..d98c95212985 100644
--- a/fs/erofs/zdata.h
+++ b/fs/erofs/zdata.h
@@ -126,10 +126,10 @@ static inline unsigned int z_erofs_pclusterpages(struct z_erofs_pcluster *pcl)
}
/*
- * bit 31: I/O error occurred on this page
- * bit 0 - 30: remaining parts to complete this page
+ * bit 30: I/O error occurred on this page
+ * bit 0 - 29: remaining parts to complete this page
*/
-#define Z_EROFS_PAGE_EIO (1 << 31)
+#define Z_EROFS_PAGE_EIO (1 << 30)
static inline void z_erofs_onlinepage_init(struct page *page)
{
