ext4: simplify some code in read_mmp_block()
My static check complains because we have:
if (!*bh)
return -ENOMEM;
if (*bh) {
The second check is unnecessary.
I've simplified this code by moving the "if (!*bh)" checks around. Also
Andreas Dilger says we should probably print a warning if sb_getblk()
fails.
[ Restructured the code so that we print a warning message as well if
the mmp block doesn't check out, and to print the error code to
disambiguate between the error cases. - TYT ]
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 8313ca3..048c52a 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -69,6 +69,7 @@
ext4_fsblk_t mmp_block)
{
struct mmp_struct *mmp;
+ int ret;
if (*bh)
clear_buffer_uptodate(*bh);
@@ -76,33 +77,36 @@
/* This would be sb_bread(sb, mmp_block), except we need to be sure
* that the MD RAID device cache has been bypassed, and that the read
* is not blocked in the elevator. */
- if (!*bh)
+ if (!*bh) {
*bh = sb_getblk(sb, mmp_block);
- if (!*bh)
- return -ENOMEM;
- if (*bh) {
- get_bh(*bh);
- lock_buffer(*bh);
- (*bh)->b_end_io = end_buffer_read_sync;
- submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
- wait_on_buffer(*bh);
- if (!buffer_uptodate(*bh)) {
- brelse(*bh);
- *bh = NULL;
+ if (!*bh) {
+ ret = -ENOMEM;
+ goto warn_exit;
}
}
- if (unlikely(!*bh)) {
- ext4_warning(sb, "Error while reading MMP block %llu",
- mmp_block);
- return -EIO;
+
+ get_bh(*bh);
+ lock_buffer(*bh);
+ (*bh)->b_end_io = end_buffer_read_sync;
+ submit_bh(READ_SYNC | REQ_META | REQ_PRIO, *bh);
+ wait_on_buffer(*bh);
+ if (!buffer_uptodate(*bh)) {
+ brelse(*bh);
+ *bh = NULL;
+ ret = -EIO;
+ goto warn_exit;
}
mmp = (struct mmp_struct *)((*bh)->b_data);
- if (le32_to_cpu(mmp->mmp_magic) != EXT4_MMP_MAGIC ||
- !ext4_mmp_csum_verify(sb, mmp))
- return -EINVAL;
+ if (le32_to_cpu(mmp->mmp_magic) == EXT4_MMP_MAGIC &&
+ ext4_mmp_csum_verify(sb, mmp))
+ return 0;
+ ret = -EINVAL;
- return 0;
+warn_exit:
+ ext4_warning(sb, "Error %d while reading MMP block %llu",
+ ret, mmp_block);
+ return ret;
}
/*