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Commit 1dd9ffc8 authored by Tao Ma's avatar Tao Ma Committed by Joel Becker
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ocfs2: optimize ocfs2_check_dir_entry() with unlikely() annotations 



In cad3f007, ext4_check_dir_entry was modified by adding some unlikely.
Ted described it as "This function gets called a lot for large
directories, and the answer is almost always 'no, no, there's no problem'.
This means using unlikely() is a good thing."
ext3 added the similar change in commit a4ae3094.

So change it accordingly in ocfs2.

Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: default avatarTao Ma <boyu.mt@taobao.com>
Signed-off-by: default avatarJoel Becker <jlbec@evilplan.org>
parent 5bc970e8

fs/ocfs2/dir.c

+7 −5
Original line number Diff line number Diff line
@@ -322,21 +322,23 @@ static int ocfs2_check_dir_entry(struct inode * dir, 
	const char *error_msg = NULL;

	const int rlen = le16_to_cpu(de->rec_len);



	if (rlen < OCFS2_DIR_REC_LEN(1))

	if (unlikely(rlen < OCFS2_DIR_REC_LEN(1)))

		error_msg = "rec_len is smaller than minimal";

	else if (rlen % 4 != 0)

	else if (unlikely(rlen % 4 != 0))

		error_msg = "rec_len % 4 != 0";

	else if (rlen < OCFS2_DIR_REC_LEN(de->name_len))

	else if (unlikely(rlen < OCFS2_DIR_REC_LEN(de->name_len)))

		error_msg = "rec_len is too small for name_len";

	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)

	else if (unlikely(

		 ((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize))

		error_msg = "directory entry across blocks";



	if (error_msg != NULL)

	if (unlikely(error_msg != NULL))

		mlog(ML_ERROR, "bad entry in directory #%llu: %s - "

		     "offset=%lu, inode=%llu, rec_len=%d, name_len=%d\n",

		     (unsigned long long)OCFS2_I(dir)->ip_blkno, error_msg,

		     offset, (unsigned long long)le64_to_cpu(de->inode), rlen,

		     de->name_len);



	return error_msg == NULL ? 1 : 0;

}