Commit 98104468 authored by Dan Carpenter's avatar Dan Carpenter Committed by Theodore Ts'o
Browse files

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: default avatarAndreas Dilger <adilger@dilger.ca>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent c642dc9e

fs/ext4/mmp.c

+25 −21
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, 
			  ext4_fsblk_t mmp_block)

{

	struct mmp_struct *mmp;

	int ret;



	if (*bh)

		clear_buffer_uptodate(*bh);
@@ -76,11 +77,14 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, 
	/* 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) {

		if (!*bh) {

			ret = -ENOMEM;

			goto warn_exit;

		}

	}



	get_bh(*bh);

	lock_buffer(*bh);

	(*bh)->b_end_io = end_buffer_read_sync;
@@ -89,20 +93,20 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh, 
	if (!buffer_uptodate(*bh)) {

		brelse(*bh);

		*bh = NULL;

		}

	}

	if (unlikely(!*bh)) {

		ext4_warning(sb, "Error while reading MMP block %llu",

			     mmp_block);

		return -EIO;

		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;



warn_exit:

	ext4_warning(sb, "Error %d while reading MMP block %llu",

		     ret, mmp_block);

	return ret;

}



/*

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