[U-Boot] [PATCH] fs: btrfs: Fix unaligned memory accesses

[Alberto Sánchez Molero]

Loading files stored with lzo compression from a btrfs filesystem was
producing unaligned memory accesses, which were causing a data abort
and a reset on an Orange Pi Zero.

The change in hash.c is not triggered by any error but follows the
same pattern. Please confirm.

Fixed according to doc/README.unaligned-memory-access.txt



Signed-off by: Alberto Sánchez Molero <alsamolero at gmail.com>
---
 fs/btrfs/compression.c | 5 +++--
 fs/btrfs/hash.c        | 3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index a59ff5a..4e685a0 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -9,6 +9,7 @@
 #include "btrfs.h"
 #include <linux/lzo.h>
 #include <u-boot/zlib.h>
+#include <asm/unaligned.h>

 static u32 decompress_lzo(const u8 *cbuf, u32 clen, u8 *dbuf, u32 dlen)
 {
@@ -19,7 +20,7 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen,
u8 *dbuf, u32 dlen)
     if (clen < 4)
         return -1;

-    tot_len = le32_to_cpu(*(u32 *) cbuf);
+    tot_len = le32_to_cpu(get_unaligned((u32 *) cbuf));
     cbuf += 4;
     clen -= 4;
     tot_len -= 4;
@@ -32,7 +33,7 @@ static u32 decompress_lzo(const u8 *cbuf, u32 clen,
u8 *dbuf, u32 dlen)
     res = 0;

     while (tot_len > 4) {
-        in_len = le32_to_cpu(*(u32 *) cbuf);
+        in_len = le32_to_cpu(get_unaligned((u32 *) cbuf));
         cbuf += 4;
         clen -= 4;

diff --git a/fs/btrfs/hash.c b/fs/btrfs/hash.c
index f8a50e5..1c75ea8 100644
--- a/fs/btrfs/hash.c
+++ b/fs/btrfs/hash.c
@@ -8,6 +8,7 @@

 #include "btrfs.h"
 #include <u-boot/crc.h>
+#include <asm/unaligned.h>

 static u32 btrfs_crc32c_table[256];

@@ -34,5 +35,5 @@ u32 btrfs_csum_data(char *data, u32 seed, size_t len)

 void btrfs_csum_final(u32 crc, void *result)
 {
-    *((u32 *) result) = cpu_to_le32(~crc);
+    put_unaligned(cpu_to_le32(~crc), (u32 *) result);
 }
-- 
2.16.0