diff mbox series

[U-boot,v2] fs: btrfs: fix the false alert of decompression failure

Message ID 20210417125213.132066-1-wqu@suse.com (mailing list archive)
State New, archived
Headers show
Series [U-boot,v2] fs: btrfs: fix the false alert of decompression failure | expand

Commit Message

Qu Wenruo April 17, 2021, 12:52 p.m. UTC
There are some cases where decompressed sectors can have padding zeros.

In kernel code, we have lines to address such situation:

        /*
         * btrfs_getblock is doing a zero on the tail of the page too,
         * but this will cover anything missing from the decompressed
         * data.
         */
        if (bytes < destlen)
                memset(kaddr+bytes, 0, destlen-bytes);
        kunmap_local(kaddr);

But not in U-boot code, thus we have some reports of U-boot failed to
read compressed files in btrfs.

Fix it by doing the same thing of the kernel, for both inline and
regular compressed extents.

Reported-by: Matwey Kornilov <matwey.kornilov@gmail.com>
Link: https://bugzilla.suse.com/show_bug.cgi?id=1183717
Fixes: a26a6bedafcf ("fs: btrfs: Introduce btrfs_read_extent_inline() and btrfs_read_extent_reg()")
Signed-off-by: Qu Wenruo <wqu@suse.com>
---
Changelog:
v2:
- Fix the bug for regular and inline compressed extents
---
 fs/btrfs/inode.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

Comments

Tom Rini April 27, 2021, 4:46 p.m. UTC | #1
On Sat, Apr 17, 2021 at 08:52:13PM +0800, Qu Wenruo wrote:

> There are some cases where decompressed sectors can have padding zeros.
> 
> In kernel code, we have lines to address such situation:
> 
>         /*
>          * btrfs_getblock is doing a zero on the tail of the page too,
>          * but this will cover anything missing from the decompressed
>          * data.
>          */
>         if (bytes < destlen)
>                 memset(kaddr+bytes, 0, destlen-bytes);
>         kunmap_local(kaddr);
> 
> But not in U-boot code, thus we have some reports of U-boot failed to
> read compressed files in btrfs.
> 
> Fix it by doing the same thing of the kernel, for both inline and
> regular compressed extents.
> 
> Reported-by: Matwey Kornilov <matwey.kornilov@gmail.com>
> Link: https://bugzilla.suse.com/show_bug.cgi?id=1183717
> Fixes: a26a6bedafcf ("fs: btrfs: Introduce btrfs_read_extent_inline() and btrfs_read_extent_reg()")
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Applied to u-boot/master, thanks!
diff mbox series

Patch

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 019d532a1a4b..2c2379303d74 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -390,10 +390,16 @@  int btrfs_read_extent_inline(struct btrfs_path *path,
 			   csize);
 	ret = btrfs_decompress(btrfs_file_extent_compression(leaf, fi),
 			       cbuf, csize, dbuf, dsize);
-	if (ret < 0 || ret != dsize) {
+	if (ret == (u32)-1) {
 		ret = -EIO;
 		goto out;
 	}
+	/*
+	 * The compressed part ends before sector boundary, the remaining needs
+	 * to be zeroed out.
+	 */
+	if (ret < dsize)
+		memset(dbuf + ret, 0, dsize - ret);
 	memcpy(dest, dbuf, dsize);
 	ret = dsize;
 out:
@@ -494,10 +500,16 @@  int btrfs_read_extent_reg(struct btrfs_path *path,
 
 	ret = btrfs_decompress(btrfs_file_extent_compression(leaf, fi), cbuf,
 			       csize, dbuf, dsize);
-	if (ret != dsize) {
+	if (ret == (u32)-1) {
 		ret = -EIO;
 		goto out;
 	}
+	/*
+	 * The compressed part ends before sector boundary, the remaining needs
+	 * to be zeroed out.
+	 */
+	if (ret < dsize)
+		memset(dbuf + ret, 0, dsize - ret);
 	/* Then copy the needed part */
 	memcpy(dest, dbuf + btrfs_file_extent_offset(leaf, fi), len);
 	ret = len;