[PATCH] Test for sb_getblk return value
This patch adds tests for the return value of sb_getblk() in the ext2/3
filesystems. In fs/buffer.c it is stated that the getblk() function never
fails. However, it does can return NULL in some situations due to I/O
errors, which may lead us to NULL pointer dereferences
Signed-off-by: Glauber de Oliveira Costa <glommer@br.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c
index 57f7910..1be78b4b 100644
--- a/fs/ext3/resize.c
+++ b/fs/ext3/resize.c
@@ -118,6 +118,8 @@
int err;
bh = sb_getblk(sb, blk);
+ if (!bh)
+ return ERR_PTR(-EIO);
if ((err = ext3_journal_get_write_access(handle, bh))) {
brelse(bh);
bh = ERR_PTR(err);
@@ -202,6 +204,10 @@
ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
gdb = sb_getblk(sb, block);
+ if (!gdb) {
+ err = -EIO;
+ goto exit_bh;
+ }
if ((err = ext3_journal_get_write_access(handle, gdb))) {
brelse(gdb);
goto exit_bh;
@@ -643,6 +649,10 @@
break;
bh = sb_getblk(sb, group * bpg + blk_off);
+ if (!bh) {
+ err = -EIO;
+ break;
+ }
ext3_debug("update metadata backup %#04lx\n",
(unsigned long)bh->b_blocknr);
if ((err = ext3_journal_get_write_access(handle, bh)))