fs: btrfs: fix the false alert of decompression failure
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>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 019d532..2c23793 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -390,10 +390,16 @@
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 @@
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;