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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: a26a6bedaf ("fs: btrfs: Introduce btrfs_read_extent_inline() and btrfs_read_extent_reg()")
Signed-off-by: Qu Wenruo <wqu@suse.com>
This commit is contained in:
Qu Wenruo 2021-04-17 20:52:13 +08:00 committed by Tom Rini
parent c2343695e3
commit dae9aeda45
1 changed files with 14 additions and 2 deletions
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16
fs/btrfs/inode.c
View File

@ -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;