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ocfs2: optimize ocfs2_check_dir_entry() with unlikely() annotations

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In cad3f00, 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 a4ae309.

So change it accordingly in ocfs2.

Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Joel Becker <jlbec@evilplan.org>
This commit is contained in:
Tao Ma 2011-01-24 23:23:30 +08:00 committed by Joel Becker
parent 5bc970e803
commit 1dd9ffc827
1 changed files with 7 additions and 5 deletions
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12
fs/ocfs2/dir.c
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@ -322,21 +322,23 @@ static int ocfs2_check_dir_entry(struct inode * dir,
const char *error_msg = NULL; const char *error_msg = NULL;
const int rlen = le16_to_cpu(de->rec_len); 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"; 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"; 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"; 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"; error_msg = "directory entry across blocks";
if (error_msg != NULL) if (unlikely(error_msg != NULL))
mlog(ML_ERROR, "bad entry in directory #%llu: %s - " mlog(ML_ERROR, "bad entry in directory #%llu: %s - "
"offset=%lu, inode=%llu, rec_len=%d, name_len=%d\n", "offset=%lu, inode=%llu, rec_len=%d, name_len=%d\n",
(unsigned long long)OCFS2_I(dir)->ip_blkno, error_msg, (unsigned long long)OCFS2_I(dir)->ip_blkno, error_msg,
offset, (unsigned long long)le64_to_cpu(de->inode), rlen, offset, (unsigned long long)le64_to_cpu(de->inode), rlen,
de->name_len); de->name_len);
return error_msg == NULL ? 1 : 0; return error_msg == NULL ? 1 : 0;
} }