[PATCH 24/24] xfs: remove xfs_inobp_check()

Dave Chinner
2020-05-22T03:50:40Z

From: Dave Chinner <dchinner@redhat.com>

This debug code is called on every xfs_iflush() call, which then
checks every inode in the buffer for non-zero unlinked list field.
Hence it checks every inode in the cluster buffer every time a
single inode on that cluster it flushed. This is resulting in:

- 38.91% 5.33% [kernel] [k] xfs_iflush ▒
- 17.70% xfs_iflush ▒
- 9.93% xfs_inobp_check ▒
4.36% xfs_buf_offset ▒

10% of the CPU time spent flushing inodes is repeatedly checking
unlinked fields in the buffer. We don't need to do this.

The other place we call xfs_inobp_check() is
xfs_iunlink_update_dinode(), and this is after we've done this
assert for the agino we are about to write into that inode:

ASSERT(xfs_verify_agino_or_null(mp, agno, next_agino));

which means we've already checked that the agino we are about to
write is not 0 on debug kernels. The inode buffer verifiers do
everything else we need, so let's just remove this debug code.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
fs/xfs/libxfs/xfs_inode_buf.c | 24 ------------------------
fs/xfs/libxfs/xfs_inode_buf.h | 6 ------
fs/xfs/xfs_inode.c | 2 --
3 files changed, 32 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 1af97235785c8..6b6f67595bf4e 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -20,30 +20,6 @@

#include <linux/iversion.h>

-/*
- * Check that none of the inode's in the buffer have a next
- * unlinked field of 0.
- */
-#if defined(DEBUG)
-void
-xfs_inobp_check(
- xfs_mount_t *mp,
- xfs_buf_t *bp)
-{
- int i;
- xfs_dinode_t *dip;
-
- for (i = 0; i < M_IGEO(mp)->inodes_per_cluster; i++) {
- dip = xfs_buf_offset(bp, i * mp->m_sb.sb_inodesize);
- if (!dip->di_next_unlinked) {
- xfs_alert(mp,
- "Detected bogus zero next_unlinked field in inode %d buffer 0x%llx.",
- i, (long long)bp->b_bn);
- }
- }
-}
-#endif
-
/*
* If we are doing readahead on an inode buffer, we might be in log recovery
* reading an inode allocation buffer that hasn't yet been replayed, and hence
diff --git a/fs/xfs/libxfs/xfs_inode_buf.h b/fs/xfs/libxfs/xfs_inode_buf.h
index 865ac493c72a2..6b08b9d060c2e 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.h
+++ b/fs/xfs/libxfs/xfs_inode_buf.h
@@ -52,12 +52,6 @@ int xfs_inode_from_disk(struct xfs_inode *ip, struct xfs_dinode *from);
void xfs_log_dinode_to_disk(struct xfs_log_dinode *from,
struct xfs_dinode *to);

-#if defined(DEBUG)
-void xfs_inobp_check(struct xfs_mount *, struct xfs_buf *);
-#else
-#define xfs_inobp_check(mp, bp)
-#endif /* DEBUG */
-
xfs_failaddr_t xfs_dinode_verify(struct xfs_mount *mp, xfs_ino_t ino,
struct xfs_dinode *dip);
xfs_failaddr_t xfs_inode_validate_extsize(struct xfs_mount *mp,
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 7db0f97e537e3..98a494e42aa6a 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -2146,7 +2146,6 @@ xfs_iunlink_update_dinode(
xfs_dinode_calc_crc(mp, dip);
xfs_trans_inode_buf(tp, ibp);
xfs_trans_log_buf(tp, ibp, offset, offset + sizeof(xfs_agino_t) - 1);
- xfs_inobp_check(mp, ibp);
}

/* Set an in-core inode's unlinked pointer and return the old value. */
@@ -3538,7 +3537,6 @@ xfs_iflush(
xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK);
if (XFS_IFORK_Q(ip))
xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK);
- xfs_inobp_check(mp, bp);

/*
* We've recorded everything logged in the inode, so we'd like to clear
--
2.26.2.761.g0e0b3e54be