[PATCH] Fix csum error for compressed data

[PATCH] Fix csum error for compressed data

[Yan Zheng]

Hello,

The decompress code doesn't take the logical offset in extent
pointer into account. If the logical offset isn't zero, data
will be decompressed into wrong pages. Thank you,

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

---
diff -urp 1/fs/btrfs/compression.c 2/fs/btrfs/compression.c
--- 1/fs/btrfs/compression.c	2008-11-08 02:16:20.000000000 +0800
+++ 2/fs/btrfs/compression.c	2008-11-10 15:25:07.000000000 +0800
@@ -505,7 +505,6 @@ int btrfs_submit_compressed_read(struct 
 	struct block_device *bdev;
 	struct bio *comp_bio;
 	u64 cur_disk_byte = (u64)bio->bi_sector << 9;
-	u64 em_len;
 	struct extent_map *em;
 	int ret;
 
@@ -524,9 +523,8 @@ int btrfs_submit_compressed_read(struct 
 	cb->errors = 0;
 	cb->inode = inode;
 
-	cb->start = em->start;
+	cb->start = em->orig_start;
 	compressed_len = em->block_len;
-	em_len = em->len;
 	free_extent_map(em);
 
 	cb->len = uncompressed_len;
@@ -545,7 +543,7 @@ int btrfs_submit_compressed_read(struct 
 	}
 	cb->nr_pages = nr_pages;
 
-	add_ra_bio_pages(inode, cb->start + em_len, cb);
+	add_ra_bio_pages(inode, em->start + em->len, cb);
 
 	if (!btrfs_test_opt(root, NODATASUM) &&
 	    !btrfs_test_flag(inode, NODATASUM)) {
diff -urp 1/fs/btrfs/extent_map.h 2/fs/btrfs/extent_map.h
--- 1/fs/btrfs/extent_map.h	2008-11-01 01:04:31.000000000 +0800
+++ 2/fs/btrfs/extent_map.h	2008-11-10 13:52:43.000000000 +0800
@@ -20,6 +20,7 @@ struct extent_map {
 	/* all of these are in bytes */
 	u64 start;
 	u64 len;
+	u64 orig_start;
 	u64 block_start;
 	u64 block_len;
 	unsigned long flags;
diff -urp 1/fs/btrfs/file.c 2/fs/btrfs/file.c
--- 1/fs/btrfs/file.c	2008-11-07 19:16:08.000000000 +0800
+++ 2/fs/btrfs/file.c	2008-11-10 13:53:12.000000000 +0800
@@ -222,6 +222,7 @@ int btrfs_drop_extent_cache(struct inode
 		    em->start < start) {
 			split->start = em->start;
 			split->len = start - em->start;
+			split->orig_start = em->orig_start;
 			split->block_start = em->block_start;
 
 			if (compressed)
@@ -243,6 +244,7 @@ int btrfs_drop_extent_cache(struct inode
 
 			split->start = start + len;
 			split->len = em->start + em->len - (start + len);
+			split->orig_start = em->orig_start;
 			split->bdev = em->bdev;
 			split->flags = flags;
 
diff -urp 1/fs/btrfs/inode.c 2/fs/btrfs/inode.c
--- 1/fs/btrfs/inode.c	2008-11-07 19:16:08.000000000 +0800
+++ 2/fs/btrfs/inode.c	2008-11-10 13:55:04.000000000 +0800
@@ -3949,6 +3949,8 @@ again:
 	    found_type == BTRFS_FILE_EXTENT_PREALLOC) {
 		em->start = extent_start;
 		em->len = extent_end - extent_start;
+		em->orig_start = extent_start -
+				 btrfs_file_extent_offset(leaf, item);
 		bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
 		if (bytenr == 0) {
 			em->block_start = EXTENT_MAP_HOLE;
@@ -3988,6 +3990,7 @@ again:
 		em->start = extent_start + extent_offset;
 		em->len = (copy_size + root->sectorsize - 1) &
 			~((u64)root->sectorsize - 1);
+		em->orig_start = EXTENT_MAP_INLINE;
 		if (compressed)
 			set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 		ptr = btrfs_file_extent_inline_start(item) + extent_offset;

Re: [PATCH] Fix csum error for compressed data

[Chris Mason]

On Mon, 2008-11-10 at 17:32 +0800, Yan Zheng wrote:
> Hello,
> 
> The decompress code doesn't take the logical offset in extent
> pointer into account. If the logical offset isn't zero, data
> will be decompressed into wrong pages. Thank you,
> 

Ah, thanks Yan.


I'll push this out along with a few other fixes from the weekend
shortly.

-chris

Re: [PATCH] Fix csum error for compressed data

[Martin Bürger]

On Monday 10 November 2008, Chris Mason wrote:
> On Mon, 2008-11-10 at 17:32 +0800, Yan Zheng wrote:
> > Hello,
> >
> > The decompress code doesn't take the logical offset in extent
> > pointer into account. If the logical offset isn't zero, data
> > will be decompressed into wrong pages. Thank you,
>
> Ah, thanks Yan.
>
>
> I'll push this out along with a few other fixes from the weekend
> shortly.
Well, if this should fix the issue I've reported last Friday I have=20
to tell you that this error still occurs during my test drives.

Best wishes,
--=20
Martin B=C3=BCrger
1024D/27C9019B@www.edu.uni-klu.ac.at/~mbuerger/key.asc
Key fingerprint =3D D10D 97EF 0C32 B337 5A12  0B6C 2D47 7575 27C9 019B
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Re: [PATCH] Fix csum error for compressed data

[Chris Mason]

On Mon, 2008-11-10 at 22:00 +0100, Martin B=C3=BCrger wrote:
> On Monday 10 November 2008, Chris Mason wrote:
> > On Mon, 2008-11-10 at 17:32 +0800, Yan Zheng wrote:
> > > Hello,
> > >
> > > The decompress code doesn't take the logical offset in extent
> > > pointer into account. If the logical offset isn't zero, data
> > > will be decompressed into wrong pages. Thank you,
> >
> > Ah, thanks Yan.
> >
> >
> > I'll push this out along with a few other fixes from the weekend
> > shortly.
> Well, if this should fix the issue I've reported last Friday I have=20
> to tell you that this error still occurs during my test drives.

Do you also have this changeset:

http://git.kernel.org/?p=3Dlinux/kernel/git/mason/btrfs-unstable.git;a=3D=
commit;h=3De04ca626baee684bea9d6239e4e1119b696101b2

-chris


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Re: [PATCH] Fix csum error for compressed data

[Martin Bürger]

On Monday 10 November 2008, Chris Mason wrote:
> On Mon, 2008-11-10 at 22:00 +0100, Martin B=C3=BCrger wrote:
> > On Monday 10 November 2008, Chris Mason wrote:
> > > On Mon, 2008-11-10 at 17:32 +0800, Yan Zheng wrote:
> > > > Hello,
> > > >
> > > > The decompress code doesn't take the logical offset in
> > > > extent pointer into account. If the logical offset isn't
> > > > zero, data will be decompressed into wrong pages. Thank
> > > > you,
> > >
> > > Ah, thanks Yan.
> > >
> > >
> > > I'll push this out along with a few other fixes from the
> > > weekend shortly.
> >
> > Well, if this should fix the issue I've reported last Friday I
> > have to tell you that this error still occurs during my test
> > drives.
>
> Do you also have this changeset:
>
> http://git.kernel.org/?p=3Dlinux/kernel/git/mason/btrfs-unstable.gi
>t;a=3Dcommit;h=3De04ca626baee684bea9d6239e4e1119b696101b2
Yes, I do.

--=20
Martin B=C3=BCrger
1024D/27C9019B@www.edu.uni-klu.ac.at/~mbuerger/key.asc
Key fingerprint =3D D10D 97EF 0C32 B337 5A12  0B6C 2D47 7575 27C9 019B
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Re: [PATCH] Fix csum error for compressed data

[Yan Zheng]

Hi Martin,

Please try following patch. Thank you,

---
diff -urp 2/fs/btrfs/file.c 5/fs/btrfs/file.c
--- 2/fs/btrfs/file.c	2008-11-11 10:43:08.000000000 +0800
+++ 5/fs/btrfs/file.c	2008-11-11 16:52:11.000000000 +0800
@@ -436,7 +436,7 @@ next_slot:
 			goto out;
 		}
 		if (recow) {
-			search_start = key.offset;
+			search_start = max(key.offset, start);
 			continue;
 		}
 		if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {

Re: [PATCH] Fix csum error for compressed data

[Martin Bürger]

On Tuesday 11 November 2008, Yan Zheng wrote:
> Hi Martin,
>
> Please try following patch. Thank you,
That fixed it.

Best wishes,
--=20
Martin B=FCrger
1024D/27C9019B@www.edu.uni-klu.ac.at/~mbuerger/key.asc
Key fingerprint =3D D10D 97EF 0C32 B337 5A12  0B6C 2D47 7575 27C9 019B
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Re: [PATCH] Fix csum error for compressed data

[Chris Mason]

On Tue, 2008-11-11 at 18:14 +0100, Martin B=C3=BCrger wrote:
> On Tuesday 11 November 2008, Yan Zheng wrote:
> > Hi Martin,
> >
> > Please try following patch. Thank you,
> That fixed it.

Thank you both, I've pushed out Yan Zheng's fix.

-chris


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