[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/inode.c b/fs/ext3/inode.c
index b5da524..5d9b00e 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -523,7 +523,6 @@
if (!nr)
break;
branch[n].key = cpu_to_le32(nr);
- keys = n+1;
/*
* Get buffer_head for parent block, zero it out
@@ -531,6 +530,9 @@
* parent to disk.
*/
bh = sb_getblk(inode->i_sb, parent);
+ if (!bh)
+ break;
+ keys = n+1;
branch[n].bh = bh;
lock_buffer(bh);
BUFFER_TRACE(bh, "call get_create_access");
@@ -864,6 +866,10 @@
if (!*errp && buffer_mapped(&dummy)) {
struct buffer_head *bh;
bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
+ if (!bh) {
+ *errp = -EIO;
+ goto err;
+ }
if (buffer_new(&dummy)) {
J_ASSERT(create != 0);
J_ASSERT(handle != 0);
@@ -896,6 +902,7 @@
}
return bh;
}
+err:
return NULL;
}