From efc5f7a9f3d887ce44b7610bc39388094b6f97d5 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Mon, 24 Feb 2025 15:48:53 -0800
Subject: [PATCH] xfs: decouple buffer readahead from the normal buffer read
path
xfs_buf_readahead_map is the only caller of xfs_buf_read_map and thus
_xfs_buf_read that is not synchronous. Split it from xfs_buf_read_map
so that the asynchronous path is self-contained and the now purely
synchronous xfs_buf_read_map / _xfs_buf_read implementation can be
simplified.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
---
fs/xfs/xfs_buf.c | 41 ++++++++++++++++++++--------------------
fs/xfs/xfs_buf.h | 2 +-
fs/xfs/xfs_log_recover.c | 2 +-
fs/xfs/xfs_trace.h | 1 +
4 files changed, 23 insertions(+), 23 deletions(-)
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index dfc1849b3314b..4ea20483d5213 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -794,18 +794,13 @@ xfs_buf_get_map(
int
_xfs_buf_read(
- struct xfs_buf *bp,
- xfs_buf_flags_t flags)
+ struct xfs_buf *bp)
{
- ASSERT(!(flags & XBF_WRITE));
ASSERT(bp->b_maps[0].bm_bn != XFS_BUF_DADDR_NULL);
bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD | XBF_DONE);
- bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
-
+ bp->b_flags |= XBF_READ;
xfs_buf_submit(bp);
- if (flags & XBF_ASYNC)
- return 0;
return xfs_buf_iowait(bp);
}
@@ -857,6 +852,8 @@ xfs_buf_read_map(
struct xfs_buf *bp;
int error;
+ ASSERT(!(flags & (XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD)));
+
flags |= XBF_READ;
*bpp = NULL;
@@ -870,21 +867,11 @@ xfs_buf_read_map(
/* Initiate the buffer read and wait. */
XFS_STATS_INC(target->bt_mount, xb_get_read);
bp->b_ops = ops;
- error = _xfs_buf_read(bp, flags);
-
- /* Readahead iodone already dropped the buffer, so exit. */
- if (flags & XBF_ASYNC)
- return 0;
+ error = _xfs_buf_read(bp);
} else {
/* Buffer already read; all we need to do is check it. */
error = xfs_buf_reverify(bp, ops);
- /* Readahead already finished; drop the buffer and exit. */
- if (flags & XBF_ASYNC) {
- xfs_buf_relse(bp);
- return 0;
- }
-
/* We do not want read in the flags */
bp->b_flags &= ~XBF_READ;
ASSERT(bp->b_ops != NULL || ops == NULL);
@@ -936,6 +923,7 @@ xfs_buf_readahead_map(
int nmaps,
const struct xfs_buf_ops *ops)
{
+ const xfs_buf_flags_t flags = XBF_READ | XBF_ASYNC | XBF_READ_AHEAD;
struct xfs_buf *bp;
/*
@@ -945,9 +933,20 @@ xfs_buf_readahead_map(
if (xfs_buftarg_is_mem(target))
return;
- xfs_buf_read_map(target, map, nmaps,
- XBF_TRYLOCK | XBF_ASYNC | XBF_READ_AHEAD, &bp, ops,
- __this_address);
+ if (xfs_buf_get_map(target, map, nmaps, flags | XBF_TRYLOCK, &bp))
+ return;
+ trace_xfs_buf_readahead(bp, 0, _RET_IP_);
+
+ if (bp->b_flags & XBF_DONE) {
+ xfs_buf_reverify(bp, ops);
+ xfs_buf_relse(bp);
+ return;
+ }
+ XFS_STATS_INC(target->bt_mount, xb_get_read);
+ bp->b_ops = ops;
+ bp->b_flags &= ~(XBF_WRITE | XBF_DONE);
+ bp->b_flags |= flags;
+ xfs_buf_submit(bp);
}
/*
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 3b4ed42e11c01..2e747555ad3fa 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -291,7 +291,7 @@ int xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
size_t numblks, xfs_buf_flags_t flags, struct xfs_buf **bpp,
const struct xfs_buf_ops *ops);
-int _xfs_buf_read(struct xfs_buf *bp, xfs_buf_flags_t flags);
+int _xfs_buf_read(struct xfs_buf *bp);
void xfs_buf_hold(struct xfs_buf *bp);
/* Releasing Buffers */
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index b3c27dbccce86..2f76531842f83 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -3380,7 +3380,7 @@ xlog_do_recover(
*/
xfs_buf_lock(bp);
xfs_buf_hold(bp);
- error = _xfs_buf_read(bp, XBF_READ);
+ error = _xfs_buf_read(bp);
if (error) {
if (!xlog_is_shutdown(log)) {
xfs_buf_ioerror_alert(bp, __this_address);
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index b29462363b815..bfc2f12490224 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -593,6 +593,7 @@ DEFINE_EVENT(xfs_buf_flags_class, name, \
DEFINE_BUF_FLAGS_EVENT(xfs_buf_find);
DEFINE_BUF_FLAGS_EVENT(xfs_buf_get);
DEFINE_BUF_FLAGS_EVENT(xfs_buf_read);
+DEFINE_BUF_FLAGS_EVENT(xfs_buf_readahead);
TRACE_EVENT(xfs_buf_ioerror,
TP_PROTO(struct xfs_buf *bp, int error, xfs_failaddr_t caller_ip),
--
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