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* [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces
@ 2014-09-25 12:34 Dave Chinner
  2014-09-25 12:34 ` [PATCH 01/11] xfs: force the log before shutting down Dave Chinner
                   ` (10 more replies)
  0 siblings, 11 replies; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

Hi folks,

This is an updated version of the patch set I first posted
here:

http://oss.sgi.com/archives/xfs/2014-08/msg00203.html

There are a few changes in the patchset as a result of review
comments and bugs that I found.

Version 2:
- change shutdown log force code so that the log IO is done before
  we mark both the filesystem and the log as being shut down.
  (prevents a godown regression in xfstests introduced by having
   xfs_buf_submit() check for shutdown)
- moved the delwri submission rework to the start of the patch set
- moved reference count fixups in error handling to the patch that
  introduced the new reference counting.
- dropped the xfs_trans_buf_read rework patch; it can be done at a
  later time after checking whether parts of the code are still
  needed or not.
- added Christoph's xfs_zero_remaining_bytes simplification
- reworked the error handling cleanups for xfs_buf_read_uncached
- updated several comments

-Dave.

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply	[flat|nested] 27+ messages in thread
* [PATCH 01/11] xfs: force the log before shutting down
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:37   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code Dave Chinner
                   ` (9 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

When we have marked the filesystem for shutdown, we want to prevent
any further buffer IO from being submitted. However, we currently
force the log after marking the filesystem as shut down, hence
allowing IO to the log *after* we have marked both the filesystem
and the log as in an error state.

Clean this up by forcing the log before we mark the filesytem with
an error. This replaces the pure CIL flush that we currently have
which works around this same issue (i.e the CIL can't be flushed
once the shutdown flags are set) and hence enables us to clean up
the logic substantially.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_log.c | 37 +++++++++----------------------------
 1 file changed, 9 insertions(+), 28 deletions(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index b1131fe..a598955 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -3924,13 +3924,14 @@ xfs_log_force_umount(
 	retval = 0;
 
 	/*
-	 * Flush the in memory commit item list before marking the log as
-	 * being shut down. We need to do it in this order to ensure all the
-	 * completed transactions are flushed to disk with the xfs_log_force()
-	 * call below.
+	 * Flush all the completed transactions to disk before marking the log
+	 * being shut down. We need to do it in this order to ensure that
+	 * completed operations are safely on disk before we shut down, and that
+	 * we don't have to issue any buffer IO after the shutdown flags are set
+	 * to guarantee this.
 	 */
 	if (!logerror)
-		xlog_cil_force(log);
+		_xfs_log_force(mp, XFS_LOG_SYNC, NULL);
 
 	/*
 	 * mark the filesystem and the as in a shutdown state and wake
@@ -3942,18 +3943,11 @@ xfs_log_force_umount(
 		XFS_BUF_DONE(mp->m_sb_bp);
 
 	/*
-	 * This flag is sort of redundant because of the mount flag, but
-	 * it's good to maintain the separation between the log and the rest
-	 * of XFS.
+	 * Mark the log and the iclogs with IO error flags to prevent any
+	 * further log IO from being issued or completed.
 	 */
 	log->l_flags |= XLOG_IO_ERROR;
-
-	/*
-	 * If we hit a log error, we want to mark all the iclogs IOERROR
-	 * while we're still holding the loglock.
-	 */
-	if (logerror)
-		retval = xlog_state_ioerror(log);
+	retval = xlog_state_ioerror(log);
 	spin_unlock(&log->l_icloglock);
 
 	/*
@@ -3966,19 +3960,6 @@ xfs_log_force_umount(
 	xlog_grant_head_wake_all(&log->l_reserve_head);
 	xlog_grant_head_wake_all(&log->l_write_head);
 
-	if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
-		ASSERT(!logerror);
-		/*
-		 * Force the incore logs to disk before shutting the
-		 * log down completely.
-		 */
-		_xfs_log_force(mp, XFS_LOG_SYNC, NULL);
-
-		spin_lock(&log->l_icloglock);
-		retval = xlog_state_ioerror(log);
-		spin_unlock(&log->l_icloglock);
-	}
-
 	/*
 	 * Wake up everybody waiting on xfs_log_force. Wake the CIL push first
 	 * as if the log writes were completed. The abort handling in the log
-- 
2.0.0

_______________________________________________
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xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
  2014-09-25 12:34 ` [PATCH 01/11] xfs: force the log before shutting down Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-25 16:19   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 03/11] xfs: synchronous buffer IO needs a reference Dave Chinner
                   ` (8 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

For the special case of delwri buffer submission and waiting, we
don't need to issue IO synchronously at all. The second pass to call
xfs_buf_iowait() can be replaced with  blocking on xfs_buf_lock() -
the buffer will be unlocked when the async IO is complete.

This formalises a sane the method of waiting for async IO - take an
extra reference, submit the IO, call xfs_buf_lock() when you want to
wait for IO completion. i.e.:

	bp = xfs_buf_find();
	xfs_buf_hold(bp);
	bp->b_flags |= XBF_ASYNC;
	xfs_buf_iosubmit(bp);
	xfs_buf_lock(bp)
	error = bp->b_error;
	....
	xfs_buf_relse(bp);

While this is somewhat racy for gathering IO errors, none of the
code that calls xfs_buf_delwri_submit() will race against other
users of the buffers being submitted. Even if they do, we don't
really care if the error is detected by the delwri code or the user
we raced against. Either way, the error will be detected and
handled.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index ec65050..f1bd238 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1813,12 +1813,17 @@ __xfs_buf_delwri_submit(
 	blk_start_plug(&plug);
 	list_for_each_entry_safe(bp, n, io_list, b_list) {
 		bp->b_flags &= ~(_XBF_DELWRI_Q | XBF_ASYNC | XBF_WRITE_FAIL);
-		bp->b_flags |= XBF_WRITE;
+		bp->b_flags |= XBF_WRITE | XBF_ASYNC;
 
-		if (!wait) {
-			bp->b_flags |= XBF_ASYNC;
+		/*
+		 * we do all Io submission async. This means if we need to wait
+		 * for IO completion we need to take an extra reference so the
+		 * buffer is still valid on the other side.
+		 */
+		if (wait)
+			xfs_buf_hold(bp);
+		else
 			list_del_init(&bp->b_list);
-		}
 		xfs_bdstrat_cb(bp);
 	}
 	blk_finish_plug(&plug);
@@ -1866,7 +1871,10 @@ xfs_buf_delwri_submit(
 		bp = list_first_entry(&io_list, struct xfs_buf, b_list);
 
 		list_del_init(&bp->b_list);
-		error2 = xfs_buf_iowait(bp);
+
+		/* locking the buffer will wait for async IO completion. */
+		xfs_buf_lock(bp);
+		error2 = bp->b_error;
 		xfs_buf_relse(bp);
 		if (!error)
 			error = error2;
-- 
2.0.0

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 03/11] xfs: synchronous buffer IO needs a reference
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
  2014-09-25 12:34 ` [PATCH 01/11] xfs: force the log before shutting down Dave Chinner
  2014-09-25 12:34 ` [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:11   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality Dave Chinner
                   ` (7 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

When synchronous IO runs IO completion work, it does so without an
IO reference or a hold reference on the buffer. The IO "hold
reference" is owned by the submitter, and released when the
submission is complete. The IO reference is released when both the
submitter and the bio end_io processing is run, and so if the io
completion work is run from IO completion context, it is run without
an IO reference.

Hence we can get the situation where the submitter can submit the
IO, see an error on the buffer and unlock and free the buffer while
there is still IO in progress. This leads to use-after-free and
memory corruption.

Fix this by taking a "sync IO hold" reference that is owned by the
IO and not released until after the buffer completion calls are run
to wake up synchronous waiters. This means that the buffer will not
be freed in any circumstance until all IO processing is completed.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_buf.c | 51 ++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 42 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index f1bd238..5d8d2e1 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1019,6 +1019,9 @@ xfs_buf_iodone_work(
 	else {
 		ASSERT(read && bp->b_ops);
 		complete(&bp->b_iowait);
+
+		/* release the !XBF_ASYNC ref now we are done. */
+		xfs_buf_rele(bp);
 	}
 }
 
@@ -1044,6 +1047,7 @@ xfs_buf_ioend(
 	} else {
 		bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
 		complete(&bp->b_iowait);
+		xfs_buf_rele(bp);
 	}
 }
 
@@ -1086,8 +1090,11 @@ xfs_bioerror(
 	xfs_buf_ioerror(bp, -EIO);
 
 	/*
-	 * We're calling xfs_buf_ioend, so delete XBF_DONE flag.
+	 * We're calling xfs_buf_ioend, so delete XBF_DONE flag. For
+	 * sync IO, xfs_buf_ioend is going to remove a ref here.
 	 */
+	if (!(bp->b_flags & XBF_ASYNC))
+		xfs_buf_hold(bp);
 	XFS_BUF_UNREAD(bp);
 	XFS_BUF_UNDONE(bp);
 	xfs_buf_stale(bp);
@@ -1383,22 +1390,48 @@ xfs_buf_iorequest(
 
 	if (bp->b_flags & XBF_WRITE)
 		xfs_buf_wait_unpin(bp);
+
+	/*
+	 * Take references to the buffer. For XBF_ASYNC buffers, holding a
+	 * reference for as long as submission takes is all that is necessary
+	 * here. The IO inherits the lock and hold count from the submitter,
+	 * and these are release during IO completion processing. Taking a hold
+	 * over submission ensures that the buffer is not freed until we have
+	 * completed all processing, regardless of when IO errors occur or are
+	 * reported.
+	 *
+	 * However, for synchronous IO, the IO does not inherit the submitters
+	 * reference count, nor the buffer lock. Hence we need to take an extra
+	 * reference to the buffer for the for the IO context so that we can
+	 * guarantee the buffer is not freed until all IO completion processing
+	 * is done. Otherwise the caller can drop their reference while the IO
+	 * is still in progress and hence trigger a use-after-free situation.
+	 */
 	xfs_buf_hold(bp);
+	if (!(bp->b_flags & XBF_ASYNC))
+		xfs_buf_hold(bp);
+
 
 	/*
-	 * Set the count to 1 initially, this will stop an I/O
-	 * completion callout which happens before we have started
-	 * all the I/O from calling xfs_buf_ioend too early.
+	 * Set the count to 1 initially, this will stop an I/O completion
+	 * callout which happens before we have started all the I/O from calling
+	 * xfs_buf_ioend too early.
 	 */
 	atomic_set(&bp->b_io_remaining, 1);
 	_xfs_buf_ioapply(bp);
+
 	/*
-	 * If _xfs_buf_ioapply failed, we'll get back here with
-	 * only the reference we took above.  _xfs_buf_ioend will
-	 * drop it to zero, so we'd better not queue it for later,
-	 * or we'll free it before it's done.
+	 * If _xfs_buf_ioapply failed or we are doing synchronous IO that
+	 * completes extremely quickly, we can get back here with only the IO
+	 * reference we took above. _xfs_buf_ioend will drop it to zero. Run
+	 * completion processing synchronously so that we don't return to the
+	 * caller with completion still pending. This avoids unnecessary context
+	 * switches associated with the end_io workqueue.
 	 */
-	_xfs_buf_ioend(bp, bp->b_error ? 0 : 1);
+	if (bp->b_error || !(bp->b_flags & XBF_ASYNC))
+		_xfs_buf_ioend(bp, 0);
+	else
+		_xfs_buf_ioend(bp, 1);
 
 	xfs_buf_rele(bp);
 }
-- 
2.0.0

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (2 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 03/11] xfs: synchronous buffer IO needs a reference Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:14   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling Dave Chinner
                   ` (6 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

We do some work in xfs_buf_ioend, and some work in
xfs_buf_iodone_work, but much of that functionality is the same.
This work can all be done in a single function, leaving
xfs_buf_iodone just a wrapper to determine if we should execute it
by workqueue or directly. hence rename xfs_buf_iodone_work to
xfs_buf_ioend(), and add a new xfs_buf_ioend_async() for places that
need async processing.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c         | 88 +++++++++++++++++++++---------------------------
 fs/xfs/xfs_buf.h         |  2 +-
 fs/xfs/xfs_buf_item.c    |  4 +--
 fs/xfs/xfs_inode.c       |  2 +-
 fs/xfs/xfs_log.c         |  2 +-
 fs/xfs/xfs_log_recover.c |  2 +-
 6 files changed, 45 insertions(+), 55 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 5d8d2e1..08f9fca 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -998,26 +998,30 @@ xfs_buf_wait_unpin(
  *	Buffer Utility Routines
  */
 
-STATIC void
-xfs_buf_iodone_work(
-	struct work_struct	*work)
+void
+xfs_buf_ioend(
+	struct xfs_buf	*bp)
 {
-	struct xfs_buf		*bp =
-		container_of(work, xfs_buf_t, b_iodone_work);
-	bool			read = !!(bp->b_flags & XBF_READ);
+	bool		read = bp->b_flags & XBF_READ;
+
+	trace_xfs_buf_iodone(bp, _RET_IP_);
 
 	bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
 
-	/* only validate buffers that were read without errors */
-	if (read && bp->b_ops && !bp->b_error && (bp->b_flags & XBF_DONE))
+	/* Only validate buffers that were read without errors */
+	if (read && !bp->b_error && bp->b_ops) {
+		ASSERT(!bp->b_iodone);
 		bp->b_ops->verify_read(bp);
+	}
+
+	if (!bp->b_error)
+		bp->b_flags |= XBF_DONE;
 
 	if (bp->b_iodone)
 		(*(bp->b_iodone))(bp);
 	else if (bp->b_flags & XBF_ASYNC)
 		xfs_buf_relse(bp);
 	else {
-		ASSERT(read && bp->b_ops);
 		complete(&bp->b_iowait);
 
 		/* release the !XBF_ASYNC ref now we are done. */
@@ -1025,30 +1029,22 @@ xfs_buf_iodone_work(
 	}
 }
 
-void
-xfs_buf_ioend(
-	struct xfs_buf	*bp,
-	int		schedule)
+static void
+xfs_buf_ioend_work(
+	struct work_struct	*work)
 {
-	bool		read = !!(bp->b_flags & XBF_READ);
-
-	trace_xfs_buf_iodone(bp, _RET_IP_);
+	struct xfs_buf		*bp =
+		container_of(work, xfs_buf_t, b_iodone_work);
 
-	if (bp->b_error == 0)
-		bp->b_flags |= XBF_DONE;
+	xfs_buf_ioend(bp);
+}
 
-	if (bp->b_iodone || (read && bp->b_ops) || (bp->b_flags & XBF_ASYNC)) {
-		if (schedule) {
-			INIT_WORK(&bp->b_iodone_work, xfs_buf_iodone_work);
-			queue_work(xfslogd_workqueue, &bp->b_iodone_work);
-		} else {
-			xfs_buf_iodone_work(&bp->b_iodone_work);
-		}
-	} else {
-		bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
-		complete(&bp->b_iowait);
-		xfs_buf_rele(bp);
-	}
+void
+xfs_buf_ioend_async(
+	struct xfs_buf	*bp)
+{
+	INIT_WORK(&bp->b_iodone_work, xfs_buf_ioend_work);
+	queue_work(xfslogd_workqueue, &bp->b_iodone_work);
 }
 
 void
@@ -1099,7 +1095,7 @@ xfs_bioerror(
 	XFS_BUF_UNDONE(bp);
 	xfs_buf_stale(bp);
 
-	xfs_buf_ioend(bp, 0);
+	xfs_buf_ioend(bp);
 
 	return -EIO;
 }
@@ -1186,15 +1182,6 @@ xfs_bwrite(
 }
 
 STATIC void
-_xfs_buf_ioend(
-	xfs_buf_t		*bp,
-	int			schedule)
-{
-	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
-		xfs_buf_ioend(bp, schedule);
-}
-
-STATIC void
 xfs_buf_bio_end_io(
 	struct bio		*bio,
 	int			error)
@@ -1211,7 +1198,8 @@ xfs_buf_bio_end_io(
 	if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
 		invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
 
-	_xfs_buf_ioend(bp, 1);
+	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
+		xfs_buf_ioend_async(bp);
 	bio_put(bio);
 }
 
@@ -1423,15 +1411,17 @@ xfs_buf_iorequest(
 	/*
 	 * If _xfs_buf_ioapply failed or we are doing synchronous IO that
 	 * completes extremely quickly, we can get back here with only the IO
-	 * reference we took above. _xfs_buf_ioend will drop it to zero. Run
-	 * completion processing synchronously so that we don't return to the
-	 * caller with completion still pending. This avoids unnecessary context
-	 * switches associated with the end_io workqueue.
+	 * reference we took above. If we drop it to zero, run completion
+	 * processing synchronously so that we don't return to the caller with
+	 * completion still pending. This avoids unnecessary context switches
+	 * associated with the end_io workqueue.
 	 */
-	if (bp->b_error || !(bp->b_flags & XBF_ASYNC))
-		_xfs_buf_ioend(bp, 0);
-	else
-		_xfs_buf_ioend(bp, 1);
+	if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
+		if (bp->b_error || !(bp->b_flags & XBF_ASYNC))
+			xfs_buf_ioend(bp);
+		else
+			xfs_buf_ioend_async(bp);
+	}
 
 	xfs_buf_rele(bp);
 }
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index c753183..4585c15 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -286,7 +286,7 @@ extern void xfs_buf_unlock(xfs_buf_t *);
 
 /* Buffer Read and Write Routines */
 extern int xfs_bwrite(struct xfs_buf *bp);
-extern void xfs_buf_ioend(xfs_buf_t *,	int);
+extern void xfs_buf_ioend(struct xfs_buf *bp);
 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
 extern void xfs_buf_iorequest(xfs_buf_t *);
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 30fa5db..3916384 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -491,7 +491,7 @@ xfs_buf_item_unpin(
 		xfs_buf_ioerror(bp, -EIO);
 		XFS_BUF_UNDONE(bp);
 		xfs_buf_stale(bp);
-		xfs_buf_ioend(bp, 0);
+		xfs_buf_ioend(bp);
 	}
 }
 
@@ -1115,7 +1115,7 @@ do_callbacks:
 	xfs_buf_do_callbacks(bp);
 	bp->b_fspriv = NULL;
 	bp->b_iodone = NULL;
-	xfs_buf_ioend(bp, 0);
+	xfs_buf_ioend(bp);
 }
 
 /*
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index c92cb48..e5bbc1f 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3062,7 +3062,7 @@ cluster_corrupt_out:
 			XFS_BUF_UNDONE(bp);
 			xfs_buf_stale(bp);
 			xfs_buf_ioerror(bp, -EIO);
-			xfs_buf_ioend(bp, 0);
+			xfs_buf_ioend(bp);
 		} else {
 			xfs_buf_stale(bp);
 			xfs_buf_relse(bp);
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index a598955..b5170e5 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1689,7 +1689,7 @@ xlog_bdstrat(
 	if (iclog->ic_state & XLOG_STATE_IOERROR) {
 		xfs_buf_ioerror(bp, -EIO);
 		xfs_buf_stale(bp);
-		xfs_buf_ioend(bp, 0);
+		xfs_buf_ioend(bp);
 		/*
 		 * It would seem logical to return EIO here, but we rely on
 		 * the log state machine to propagate I/O errors instead of
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 29e101f..02ad115 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -383,7 +383,7 @@ xlog_recover_iodone(
 					SHUTDOWN_META_IO_ERROR);
 	}
 	bp->b_iodone = NULL;
-	xfs_buf_ioend(bp, 0);
+	xfs_buf_ioend(bp);
 }
 
 /*
-- 
2.0.0

_______________________________________________
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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (3 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:15   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 06/11] xfs: kill xfs_bdstrat_cb Dave Chinner
                   ` (5 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

Currently the report of a bio error from completion
immediately marks the buffer with an error. The issue is that this
is racy w.r.t. synchronous IO - the submitter can see b_error being
set before the IO is complete, and hence we cannot differentiate
between submission failures and completion failures.

Add an internal b_io_error field protected by the b_lock to catch IO
completion errors, and only propagate that to the buffer during
final IO completion handling. Hence we can tell in xfs_buf_iorequest
if we've had a submission failure bey checking bp->b_error before
dropping our b_io_remaining reference - that reference will prevent
b_io_error values from being propagated to b_error in the event that
completion races with submission.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c | 18 ++++++++++++++++--
 fs/xfs/xfs_buf.h |  1 +
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 08f9fca..a8f4a39 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1008,6 +1008,13 @@ xfs_buf_ioend(
 
 	bp->b_flags &= ~(XBF_READ | XBF_WRITE | XBF_READ_AHEAD);
 
+	/*
+	 * Pull in IO completion errors now. We are guaranteed to be running
+	 * single threaded, so we don't need the lock to read b_io_error.
+	 */
+	if (!bp->b_error && bp->b_io_error)
+		xfs_buf_ioerror(bp, bp->b_io_error);
+
 	/* Only validate buffers that were read without errors */
 	if (read && !bp->b_error && bp->b_ops) {
 		ASSERT(!bp->b_iodone);
@@ -1192,8 +1199,12 @@ xfs_buf_bio_end_io(
 	 * don't overwrite existing errors - otherwise we can lose errors on
 	 * buffers that require multiple bios to complete.
 	 */
-	if (!bp->b_error)
-		xfs_buf_ioerror(bp, error);
+	if (error) {
+		spin_lock(&bp->b_lock);
+		if (!bp->b_io_error)
+			bp->b_io_error = error;
+		spin_unlock(&bp->b_lock);
+	}
 
 	if (!bp->b_error && xfs_buf_is_vmapped(bp) && (bp->b_flags & XBF_READ))
 		invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
@@ -1379,6 +1390,9 @@ xfs_buf_iorequest(
 	if (bp->b_flags & XBF_WRITE)
 		xfs_buf_wait_unpin(bp);
 
+	/* clear the internal error state to avoid spurious errors */
+	bp->b_io_error = 0;
+
 	/*
 	 * Take references to the buffer. For XBF_ASYNC buffers, holding a
 	 * reference for as long as submission takes is all that is necessary
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 4585c15..44db8cd 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -158,6 +158,7 @@ typedef struct xfs_buf {
 	struct list_head	b_lru;		/* lru list */
 	spinlock_t		b_lock;		/* internal state lock */
 	unsigned int		b_state;	/* internal state flags */
+	int			b_io_error;	/* internal IO error state */
 	wait_queue_head_t	b_waiters;	/* unpin waiters */
 	struct list_head	b_list;
 	struct xfs_perag	*b_pag;		/* contains rbtree root */
-- 
2.0.0

_______________________________________________
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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 06/11] xfs: kill xfs_bdstrat_cb
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (4 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-25 12:34 ` [PATCH 07/11] xfs: xfs_bioerror can die Dave Chinner
                   ` (4 subsequent siblings)
  10 siblings, 0 replies; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

Only has two callers, and is just a shutdown check and error handler
around xfs_buf_iorequest. However, the error handling is a mess of
read and write semantics, and both internal callers only call it for
writes. Hence kill the wrapper, and follow up with a patch to
sanitise the error handling.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_buf.c | 48 +++++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 23 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index a8f4a39..411111a 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1146,27 +1146,6 @@ xfs_bioerror_relse(
 	return -EIO;
 }
 
-STATIC int
-xfs_bdstrat_cb(
-	struct xfs_buf	*bp)
-{
-	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
-		trace_xfs_bdstrat_shut(bp, _RET_IP_);
-		/*
-		 * Metadata write that didn't get logged but
-		 * written delayed anyway. These aren't associated
-		 * with a transaction, and can be ignored.
-		 */
-		if (!bp->b_iodone && !XFS_BUF_ISREAD(bp))
-			return xfs_bioerror_relse(bp);
-		else
-			return xfs_bioerror(bp);
-	}
-
-	xfs_buf_iorequest(bp);
-	return 0;
-}
-
 int
 xfs_bwrite(
 	struct xfs_buf		*bp)
@@ -1178,7 +1157,20 @@ xfs_bwrite(
 	bp->b_flags |= XBF_WRITE;
 	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q | XBF_WRITE_FAIL);
 
-	xfs_bdstrat_cb(bp);
+	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+		trace_xfs_bdstrat_shut(bp, _RET_IP_);
+
+		/*
+		 * Metadata write that didn't get logged but written anyway.
+		 * These aren't associated with a transaction, and can be
+		 * ignored.
+		 */
+		if (!bp->b_iodone)
+			return xfs_bioerror_relse(bp);
+		return xfs_bioerror(bp);
+	}
+
+	xfs_buf_iorequest(bp);
 
 	error = xfs_buf_iowait(bp);
 	if (error) {
@@ -1861,7 +1853,17 @@ __xfs_buf_delwri_submit(
 			xfs_buf_hold(bp);
 		else
 			list_del_init(&bp->b_list);
-		xfs_bdstrat_cb(bp);
+
+		if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+			trace_xfs_bdstrat_shut(bp, _RET_IP_);
+
+			if (!bp->b_iodone)
+				xfs_bioerror_relse(bp);
+			else
+				xfs_bioerror(bp);
+			continue;
+		}
+		xfs_buf_iorequest(bp);
 	}
 	blk_finish_plug(&plug);
 
-- 
2.0.0

_______________________________________________
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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 07/11] xfs: xfs_bioerror can die.
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (5 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 06/11] xfs: kill xfs_bdstrat_cb Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:16   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 08/11] xfs: kill xfs_bioerror_relse Dave Chinner
                   ` (3 subsequent siblings)
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

Internal buffer write error handling is a mess due to the unnatural
split between xfs_bioerror and xfs_bioerror_relse().

xfs_bwrite() only does sync IO and determines the handler to
call based on b_iodone, so for this caller the only difference
between xfs_bioerror() and xfs_bioerror_release() is the XBF_DONE
flag. We don't care what the XBF_DONE flag state is because we stale
the buffer in both paths - the next buffer lookup will clear
XBF_DONE because XBF_STALE is set. Hence we can use common
error handling for xfs_bwrite().

__xfs_buf_delwri_submit() is a similar - it's only ever called
on writes - all sync or async - and again there's no reason to
handle them any differently at all.

Clean up the nasty error handling and remove xfs_bioerror().

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c | 58 ++++++++++++--------------------------------------------
 1 file changed, 12 insertions(+), 46 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 411111a..cc6a558 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1075,39 +1075,6 @@ xfs_buf_ioerror_alert(
 }
 
 /*
- * Called when we want to stop a buffer from getting written or read.
- * We attach the EIO error, muck with its flags, and call xfs_buf_ioend
- * so that the proper iodone callbacks get called.
- */
-STATIC int
-xfs_bioerror(
-	xfs_buf_t *bp)
-{
-#ifdef XFSERRORDEBUG
-	ASSERT(XFS_BUF_ISREAD(bp) || bp->b_iodone);
-#endif
-
-	/*
-	 * No need to wait until the buffer is unpinned, we aren't flushing it.
-	 */
-	xfs_buf_ioerror(bp, -EIO);
-
-	/*
-	 * We're calling xfs_buf_ioend, so delete XBF_DONE flag. For
-	 * sync IO, xfs_buf_ioend is going to remove a ref here.
-	 */
-	if (!(bp->b_flags & XBF_ASYNC))
-		xfs_buf_hold(bp);
-	XFS_BUF_UNREAD(bp);
-	XFS_BUF_UNDONE(bp);
-	xfs_buf_stale(bp);
-
-	xfs_buf_ioend(bp);
-
-	return -EIO;
-}
-
-/*
  * Same as xfs_bioerror, except that we are releasing the buffer
  * here ourselves, and avoiding the xfs_buf_ioend call.
  * This is meant for userdata errors; metadata bufs come with
@@ -1155,19 +1122,19 @@ xfs_bwrite(
 	ASSERT(xfs_buf_islocked(bp));
 
 	bp->b_flags |= XBF_WRITE;
-	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q | XBF_WRITE_FAIL);
+	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
+			 XBF_WRITE_FAIL | XBF_DONE);
 
 	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
 		trace_xfs_bdstrat_shut(bp, _RET_IP_);
 
-		/*
-		 * Metadata write that didn't get logged but written anyway.
-		 * These aren't associated with a transaction, and can be
-		 * ignored.
-		 */
-		if (!bp->b_iodone)
-			return xfs_bioerror_relse(bp);
-		return xfs_bioerror(bp);
+		xfs_buf_ioerror(bp, -EIO);
+		xfs_buf_stale(bp);
+
+		/* sync IO, xfs_buf_ioend is going to remove a ref here */
+		xfs_buf_hold(bp);
+		xfs_buf_ioend(bp);
+		return -EIO;
 	}
 
 	xfs_buf_iorequest(bp);
@@ -1857,10 +1824,9 @@ __xfs_buf_delwri_submit(
 		if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
 			trace_xfs_bdstrat_shut(bp, _RET_IP_);
 
-			if (!bp->b_iodone)
-				xfs_bioerror_relse(bp);
-			else
-				xfs_bioerror(bp);
+			xfs_buf_ioerror(bp, -EIO);
+			xfs_buf_stale(bp);
+			xfs_buf_ioend(bp);
 			continue;
 		}
 		xfs_buf_iorequest(bp);
-- 
2.0.0

_______________________________________________
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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 08/11] xfs: kill xfs_bioerror_relse
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (6 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 07/11] xfs: xfs_bioerror can die Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:18   ` Christoph Hellwig
  2014-09-29 19:09   ` Brian Foster
  2014-09-25 12:34 ` [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait] Dave Chinner
                   ` (2 subsequent siblings)
  10 siblings, 2 replies; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

There is only one caller now - xfs_trans_read_buf_map() - and it has
very well defined call semantics - read, synchronous, and b_iodone
is NULL. Hence it's pretty clear what error handling is necessary
for this case. The bigger problem of untangling
xfs_trans_read_buf_map error handling is left to a future patch.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c       | 39 ---------------------------------------
 fs/xfs/xfs_buf.h       |  2 --
 fs/xfs/xfs_trans_buf.c |  9 ++++++---
 3 files changed, 6 insertions(+), 44 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index cc6a558..4696ff5 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1074,45 +1074,6 @@ xfs_buf_ioerror_alert(
 		(__uint64_t)XFS_BUF_ADDR(bp), func, -bp->b_error, bp->b_length);
 }
 
-/*
- * Same as xfs_bioerror, except that we are releasing the buffer
- * here ourselves, and avoiding the xfs_buf_ioend call.
- * This is meant for userdata errors; metadata bufs come with
- * iodone functions attached, so that we can track down errors.
- */
-int
-xfs_bioerror_relse(
-	struct xfs_buf	*bp)
-{
-	int64_t		fl = bp->b_flags;
-	/*
-	 * No need to wait until the buffer is unpinned.
-	 * We aren't flushing it.
-	 *
-	 * chunkhold expects B_DONE to be set, whether
-	 * we actually finish the I/O or not. We don't want to
-	 * change that interface.
-	 */
-	XFS_BUF_UNREAD(bp);
-	XFS_BUF_DONE(bp);
-	xfs_buf_stale(bp);
-	bp->b_iodone = NULL;
-	if (!(fl & XBF_ASYNC)) {
-		/*
-		 * Mark b_error and B_ERROR _both_.
-		 * Lot's of chunkcache code assumes that.
-		 * There's no reason to mark error for
-		 * ASYNC buffers.
-		 */
-		xfs_buf_ioerror(bp, -EIO);
-		complete(&bp->b_iowait);
-	} else {
-		xfs_buf_relse(bp);
-	}
-
-	return -EIO;
-}
-
 int
 xfs_bwrite(
 	struct xfs_buf		*bp)
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 44db8cd..d8f57f6 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -297,8 +297,6 @@ extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
 #define xfs_buf_zero(bp, off, len) \
 	    xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
 
-extern int xfs_bioerror_relse(struct xfs_buf *);
-
 /* Buffer Utility Routines */
 extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
 
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index 96c898e..db4be5b 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -324,11 +324,14 @@ xfs_trans_read_buf_map(
 			 */
 			if (XFS_FORCED_SHUTDOWN(mp)) {
 				trace_xfs_bdstrat_shut(bp, _RET_IP_);
-				xfs_bioerror_relse(bp);
-			} else {
-				xfs_buf_iorequest(bp);
+				bp->b_flags &= ~(XBF_READ | XBF_DONE);
+				xfs_buf_ioerror(bp, -EIO);
+				xfs_buf_stale(bp);
+				xfs_buf_relse(bp);
+				return -EIO;
 			}
 
+			xfs_buf_iorequest(bp);
 			error = xfs_buf_iowait(bp);
 			if (error) {
 				xfs_buf_ioerror_alert(bp, __func__);
-- 
2.0.0

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait]
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (7 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 08/11] xfs: kill xfs_bioerror_relse Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 12:33   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly Dave Chinner
  2014-09-25 12:34 ` [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes Dave Chinner
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

There is a lot of cookie-cutter code that looks like:

	if (shutdown)
		handle buffer error
	xfs_buf_iorequest(bp)
	error = xfs_buf_iowait(bp)
	if (error)
		handle buffer error

spread through XFS. There's significant complexity now in
xfs_buf_iorequest() to specifically handle this sort of synchronous
IO pattern, but there's all sorts of nasty surprises in different
error handling code dependent on who owns the buffer references and
the locks.

Pull this pattern into a single helper, where we can hide all the
synchronous IO warts and hence make the error handling for all the
callers much saner. This removes the need for a special extra
reference to protect IO completion processing, as we can now hold a
single reference across dispatch and waiting, simplifying the sync
IO smeantics and error handling.

In doing this, also rename xfs_buf_iorequest to xfs_buf_submit and
make it explicitly handle on asynchronous IO. This forces all users
to be switched specifically to one interface or the other and
removes any ambiguity between how the interfaces are to be used. It
also means that xfs_buf_iowait() goes away.

For the special case of delwri buffer submission and waiting, we
don't need to issue IO synchronously at all. The second pass to cal
xfs_buf_iowait() can now just block on xfs_buf_lock() - the buffer
will be unlocked when the async IO is complete. This formalises a
sane the method of waiting for async IO - take an extra reference,
submit the IO, call xfs_buf_lock() when you want to wait for IO
completion. i.e.:

	bp = xfs_buf_find();
	xfs_buf_hold(bp);
	bp->b_flags |= XBF_ASYNC;
	xfs_buf_iosubmit(bp);
	xfs_buf_lock(bp)
	error = bp->b_error;
	....
	xfs_buf_relse(bp);

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_bmap_util.c   |  14 +---
 fs/xfs/xfs_buf.c         | 169 ++++++++++++++++++++++++++---------------------
 fs/xfs/xfs_buf.h         |   4 +-
 fs/xfs/xfs_buf_item.c    |   4 +-
 fs/xfs/xfs_log.c         |   2 +-
 fs/xfs/xfs_log_recover.c |  30 ++++-----
 fs/xfs/xfs_trace.h       |   3 +-
 fs/xfs/xfs_trans_buf.c   |  19 +-----
 8 files changed, 117 insertions(+), 128 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index d8b77b5..41d9488 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1157,12 +1157,7 @@ xfs_zero_remaining_bytes(
 		XFS_BUF_READ(bp);
 		XFS_BUF_SET_ADDR(bp, xfs_fsb_to_db(ip, imap.br_startblock));
 
-		if (XFS_FORCED_SHUTDOWN(mp)) {
-			error = -EIO;
-			break;
-		}
-		xfs_buf_iorequest(bp);
-		error = xfs_buf_iowait(bp);
+		error = xfs_buf_submit_wait(bp);
 		if (error) {
 			xfs_buf_ioerror_alert(bp,
 					"xfs_zero_remaining_bytes(read)");
@@ -1175,12 +1170,7 @@ xfs_zero_remaining_bytes(
 		XFS_BUF_UNREAD(bp);
 		XFS_BUF_WRITE(bp);
 
-		if (XFS_FORCED_SHUTDOWN(mp)) {
-			error = -EIO;
-			break;
-		}
-		xfs_buf_iorequest(bp);
-		error = xfs_buf_iowait(bp);
+		error = xfs_buf_submit_wait(bp);
 		if (error) {
 			xfs_buf_ioerror_alert(bp,
 					"xfs_zero_remaining_bytes(write)");
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 4696ff5..d1d3fe6 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -623,10 +623,11 @@ _xfs_buf_read(
 	bp->b_flags &= ~(XBF_WRITE | XBF_ASYNC | XBF_READ_AHEAD);
 	bp->b_flags |= flags & (XBF_READ | XBF_ASYNC | XBF_READ_AHEAD);
 
-	xfs_buf_iorequest(bp);
-	if (flags & XBF_ASYNC)
+	if (flags & XBF_ASYNC) {
+		xfs_buf_submit(bp);
 		return 0;
-	return xfs_buf_iowait(bp);
+	}
+	return xfs_buf_submit_wait(bp);
 }
 
 xfs_buf_t *
@@ -708,12 +709,7 @@ xfs_buf_read_uncached(
 	bp->b_flags |= XBF_READ;
 	bp->b_ops = ops;
 
-	if (XFS_FORCED_SHUTDOWN(target->bt_mount)) {
-		xfs_buf_relse(bp);
-		return NULL;
-	}
-	xfs_buf_iorequest(bp);
-	xfs_buf_iowait(bp);
+	xfs_buf_submit_wait(bp);
 	return bp;
 }
 
@@ -1028,12 +1024,8 @@ xfs_buf_ioend(
 		(*(bp->b_iodone))(bp);
 	else if (bp->b_flags & XBF_ASYNC)
 		xfs_buf_relse(bp);
-	else {
+	else
 		complete(&bp->b_iowait);
-
-		/* release the !XBF_ASYNC ref now we are done. */
-		xfs_buf_rele(bp);
-	}
 }
 
 static void
@@ -1086,21 +1078,7 @@ xfs_bwrite(
 	bp->b_flags &= ~(XBF_ASYNC | XBF_READ | _XBF_DELWRI_Q |
 			 XBF_WRITE_FAIL | XBF_DONE);
 
-	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
-		trace_xfs_bdstrat_shut(bp, _RET_IP_);
-
-		xfs_buf_ioerror(bp, -EIO);
-		xfs_buf_stale(bp);
-
-		/* sync IO, xfs_buf_ioend is going to remove a ref here */
-		xfs_buf_hold(bp);
-		xfs_buf_ioend(bp);
-		return -EIO;
-	}
-
-	xfs_buf_iorequest(bp);
-
-	error = xfs_buf_iowait(bp);
+	error = xfs_buf_submit_wait(bp);
 	if (error) {
 		xfs_force_shutdown(bp->b_target->bt_mount,
 				   SHUTDOWN_META_IO_ERROR);
@@ -1209,7 +1187,7 @@ next_chunk:
 	} else {
 		/*
 		 * This is guaranteed not to be the last io reference count
-		 * because the caller (xfs_buf_iorequest) holds a count itself.
+		 * because the caller (xfs_buf_submit) holds a count itself.
 		 */
 		atomic_dec(&bp->b_io_remaining);
 		xfs_buf_ioerror(bp, -EIO);
@@ -1299,13 +1277,29 @@ _xfs_buf_ioapply(
 	blk_finish_plug(&plug);
 }
 
+/*
+ * Asynchronous IO submission path. This transfers the buffer lock ownership and
+ * the current reference to the IO. It is not safe to reference the buffer after
+ * a call to this function unless the caller holds an additional reference
+ * itself.
+ */
 void
-xfs_buf_iorequest(
-	xfs_buf_t		*bp)
+xfs_buf_submit(
+	struct xfs_buf	*bp)
 {
-	trace_xfs_buf_iorequest(bp, _RET_IP_);
+	trace_xfs_buf_submit(bp, _RET_IP_);
 
 	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
+	ASSERT(bp->b_flags & XBF_ASYNC);
+
+	/* on shutdown we stale and complete the buffer immediately */
+	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+		xfs_buf_ioerror(bp, -EIO);
+		bp->b_flags &= ~XBF_DONE;
+		xfs_buf_stale(bp);
+		xfs_buf_ioend(bp);
+		return;
+	}
 
 	if (bp->b_flags & XBF_WRITE)
 		xfs_buf_wait_unpin(bp);
@@ -1314,25 +1308,14 @@ xfs_buf_iorequest(
 	bp->b_io_error = 0;
 
 	/*
-	 * Take references to the buffer. For XBF_ASYNC buffers, holding a
-	 * reference for as long as submission takes is all that is necessary
-	 * here. The IO inherits the lock and hold count from the submitter,
-	 * and these are release during IO completion processing. Taking a hold
-	 * over submission ensures that the buffer is not freed until we have
-	 * completed all processing, regardless of when IO errors occur or are
-	 * reported.
-	 *
-	 * However, for synchronous IO, the IO does not inherit the submitters
-	 * reference count, nor the buffer lock. Hence we need to take an extra
-	 * reference to the buffer for the for the IO context so that we can
-	 * guarantee the buffer is not freed until all IO completion processing
-	 * is done. Otherwise the caller can drop their reference while the IO
-	 * is still in progress and hence trigger a use-after-free situation.
+	 * The caller's reference is released during I/O completion.
+	 * This occurs some time after the last b_io_remaining reference is
+	 * released, so after we drop our Io reference we have to have some
+	 * other reference to ensure the buffer doesn't go away from underneath
+	 * us. Take a direct reference to ensure we have safe access to the
+	 * buffer until we are finished with it.
 	 */
 	xfs_buf_hold(bp);
-	if (!(bp->b_flags & XBF_ASYNC))
-		xfs_buf_hold(bp);
-
 
 	/*
 	 * Set the count to 1 initially, this will stop an I/O completion
@@ -1343,40 +1326,82 @@ xfs_buf_iorequest(
 	_xfs_buf_ioapply(bp);
 
 	/*
-	 * If _xfs_buf_ioapply failed or we are doing synchronous IO that
-	 * completes extremely quickly, we can get back here with only the IO
-	 * reference we took above. If we drop it to zero, run completion
-	 * processing synchronously so that we don't return to the caller with
-	 * completion still pending. This avoids unnecessary context switches
-	 * associated with the end_io workqueue.
+	 * If _xfs_buf_ioapply failed, we can get back here with only the IO
+	 * reference we took above. If we drop it to zero, run completion so
+	 * that we don't return to the caller with completion still pending.
 	 */
 	if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
-		if (bp->b_error || !(bp->b_flags & XBF_ASYNC))
+		if (bp->b_error)
 			xfs_buf_ioend(bp);
 		else
 			xfs_buf_ioend_async(bp);
 	}
 
 	xfs_buf_rele(bp);
+	/* Note: it is not safe to reference bp now we've dropped our ref */
 }
 
 /*
- * Waits for I/O to complete on the buffer supplied.  It returns immediately if
- * no I/O is pending or there is already a pending error on the buffer, in which
- * case nothing will ever complete.  It returns the I/O error code, if any, or
- * 0 if there was no error.
+ * Synchronous buffer IO submission path, read or write.
  */
 int
-xfs_buf_iowait(
-	xfs_buf_t		*bp)
+xfs_buf_submit_wait(
+	struct xfs_buf	*bp)
 {
-	trace_xfs_buf_iowait(bp, _RET_IP_);
+	int		error;
 
-	if (!bp->b_error)
-		wait_for_completion(&bp->b_iowait);
+	trace_xfs_buf_submit_wait(bp, _RET_IP_);
+
+	ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC)));
 
+	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+		xfs_buf_ioerror(bp, -EIO);
+		xfs_buf_stale(bp);
+		bp->b_flags &= ~XBF_DONE;
+		return -EIO;
+	}
+
+	if (bp->b_flags & XBF_WRITE)
+		xfs_buf_wait_unpin(bp);
+
+	/* clear the internal error state to avoid spurious errors */
+	bp->b_io_error = 0;
+
+	/*
+	 * For synchronous IO, the IO does not inherit the submitters reference
+	 * count, nor the buffer lock. Hence we cannot release the reference we
+	 * are about to take until we've waited for all IO completion to occur,
+	 * including any xfs_buf_ioend_async() work that may be pending.
+	 */
+	xfs_buf_hold(bp);
+
+	/*
+	 * Set the count to 1 initially, this will stop an I/O completion
+	 * callout which happens before we have started all the I/O from calling
+	 * xfs_buf_ioend too early.
+	 */
+	atomic_set(&bp->b_io_remaining, 1);
+	_xfs_buf_ioapply(bp);
+
+	/*
+	 * make sure we run completion synchronously if it raced with us and is
+	 * already complete.
+	 */
+	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
+		xfs_buf_ioend(bp);
+
+	/* wait for completion before gathering the error from the buffer */
+	trace_xfs_buf_iowait(bp, _RET_IP_);
+	wait_for_completion(&bp->b_iowait);
 	trace_xfs_buf_iowait_done(bp, _RET_IP_);
-	return bp->b_error;
+	error = bp->b_error;
+
+	/*
+	 * all done now, we can release the hold that keeps the buffer
+	 * referenced for the entire IO.
+	 */
+	xfs_buf_rele(bp);
+	return error;
 }
 
 xfs_caddr_t
@@ -1782,15 +1807,7 @@ __xfs_buf_delwri_submit(
 		else
 			list_del_init(&bp->b_list);
 
-		if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
-			trace_xfs_bdstrat_shut(bp, _RET_IP_);
-
-			xfs_buf_ioerror(bp, -EIO);
-			xfs_buf_stale(bp);
-			xfs_buf_ioend(bp);
-			continue;
-		}
-		xfs_buf_iorequest(bp);
+		xfs_buf_submit(bp);
 	}
 	blk_finish_plug(&plug);
 
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index d8f57f6..0acfc30 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -290,8 +290,8 @@ extern int xfs_bwrite(struct xfs_buf *bp);
 extern void xfs_buf_ioend(struct xfs_buf *bp);
 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
-extern void xfs_buf_iorequest(xfs_buf_t *);
-extern int xfs_buf_iowait(xfs_buf_t *);
+extern void xfs_buf_submit(struct xfs_buf *bp);
+extern int xfs_buf_submit_wait(struct xfs_buf *bp);
 extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
 				xfs_buf_rw_t);
 #define xfs_buf_zero(bp, off, len) \
diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 3916384..f159695 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -1081,7 +1081,7 @@ xfs_buf_iodone_callbacks(
 	 * a way to shut the filesystem down if the writes keep failing.
 	 *
 	 * In practice we'll shut the filesystem down soon as non-transient
-	 * erorrs tend to affect the whole device and a failing log write
+	 * errors tend to affect the whole device and a failing log write
 	 * will make us give up.  But we really ought to do better here.
 	 */
 	if (XFS_BUF_ISASYNC(bp)) {
@@ -1094,7 +1094,7 @@ xfs_buf_iodone_callbacks(
 		if (!(bp->b_flags & (XBF_STALE|XBF_WRITE_FAIL))) {
 			bp->b_flags |= XBF_WRITE | XBF_ASYNC |
 				       XBF_DONE | XBF_WRITE_FAIL;
-			xfs_buf_iorequest(bp);
+			xfs_buf_submit(bp);
 		} else {
 			xfs_buf_relse(bp);
 		}
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index b5170e5..ed4845f 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1699,7 +1699,7 @@ xlog_bdstrat(
 		return 0;
 	}
 
-	xfs_buf_iorequest(bp);
+	xfs_buf_submit(bp);
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 02ad115..c6427b3 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -193,12 +193,8 @@ xlog_bread_noalign(
 	bp->b_io_length = nbblks;
 	bp->b_error = 0;
 
-	if (XFS_FORCED_SHUTDOWN(log->l_mp))
-		return -EIO;
-
-	xfs_buf_iorequest(bp);
-	error = xfs_buf_iowait(bp);
-	if (error)
+	error = xfs_buf_submit_wait(bp);
+	if (error && !XFS_FORCED_SHUTDOWN(log->l_mp))
 		xfs_buf_ioerror_alert(bp, __func__);
 	return error;
 }
@@ -378,9 +374,11 @@ xlog_recover_iodone(
 		 * We're not going to bother about retrying
 		 * this during recovery. One strike!
 		 */
-		xfs_buf_ioerror_alert(bp, __func__);
-		xfs_force_shutdown(bp->b_target->bt_mount,
-					SHUTDOWN_META_IO_ERROR);
+		if (!XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
+			xfs_buf_ioerror_alert(bp, __func__);
+			xfs_force_shutdown(bp->b_target->bt_mount,
+						SHUTDOWN_META_IO_ERROR);
+		}
 	}
 	bp->b_iodone = NULL;
 	xfs_buf_ioend(bp);
@@ -4400,16 +4398,12 @@ xlog_do_recover(
 	XFS_BUF_UNASYNC(bp);
 	bp->b_ops = &xfs_sb_buf_ops;
 
-	if (XFS_FORCED_SHUTDOWN(log->l_mp)) {
-		xfs_buf_relse(bp);
-		return -EIO;
-	}
-
-	xfs_buf_iorequest(bp);
-	error = xfs_buf_iowait(bp);
+	error = xfs_buf_submit_wait(bp);
 	if (error) {
-		xfs_buf_ioerror_alert(bp, __func__);
-		ASSERT(0);
+		if (!XFS_FORCED_SHUTDOWN(log->l_mp)) {
+			xfs_buf_ioerror_alert(bp, __func__);
+			ASSERT(0);
+		}
 		xfs_buf_relse(bp);
 		return error;
 	}
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 152f827..51372e3 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -349,7 +349,8 @@ DEFINE_BUF_EVENT(xfs_buf_free);
 DEFINE_BUF_EVENT(xfs_buf_hold);
 DEFINE_BUF_EVENT(xfs_buf_rele);
 DEFINE_BUF_EVENT(xfs_buf_iodone);
-DEFINE_BUF_EVENT(xfs_buf_iorequest);
+DEFINE_BUF_EVENT(xfs_buf_submit);
+DEFINE_BUF_EVENT(xfs_buf_submit_wait);
 DEFINE_BUF_EVENT(xfs_buf_bawrite);
 DEFINE_BUF_EVENT(xfs_buf_lock);
 DEFINE_BUF_EVENT(xfs_buf_lock_done);
diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
index db4be5b..e2b2216 100644
--- a/fs/xfs/xfs_trans_buf.c
+++ b/fs/xfs/xfs_trans_buf.c
@@ -318,23 +318,10 @@ xfs_trans_read_buf_map(
 			XFS_BUF_READ(bp);
 			bp->b_ops = ops;
 
-			/*
-			 * XXX(hch): clean up the error handling here to be less
-			 * of a mess..
-			 */
-			if (XFS_FORCED_SHUTDOWN(mp)) {
-				trace_xfs_bdstrat_shut(bp, _RET_IP_);
-				bp->b_flags &= ~(XBF_READ | XBF_DONE);
-				xfs_buf_ioerror(bp, -EIO);
-				xfs_buf_stale(bp);
-				xfs_buf_relse(bp);
-				return -EIO;
-			}
-
-			xfs_buf_iorequest(bp);
-			error = xfs_buf_iowait(bp);
+			error = xfs_buf_submit_wait(bp);
 			if (error) {
-				xfs_buf_ioerror_alert(bp, __func__);
+				if (!XFS_FORCED_SHUTDOWN(mp))
+					xfs_buf_ioerror_alert(bp, __func__);
 				xfs_buf_relse(bp);
 				/*
 				 * We can gracefully recover from most read
-- 
2.0.0

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (8 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait] Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:21   ` Christoph Hellwig
  2014-09-25 12:34 ` [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes Dave Chinner
  10 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Dave Chinner <dchinner@redhat.com>

xfs_buf_read_uncached() has two failure modes. If can either return
NULL or bp->b_error != 0 depending on the type of failure, and not
all callers check for both. Fix it up.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c     | 18 ++++++++++++----
 fs/xfs/xfs_buf.h     |  6 +++---
 fs/xfs/xfs_fsops.c   | 11 +++-------
 fs/xfs/xfs_mount.c   | 58 +++++++++++++++++++++++++---------------------------
 fs/xfs/xfs_rtalloc.c | 30 +++++++++++----------------
 5 files changed, 60 insertions(+), 63 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d1d3fe6..0ac54a0 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -688,29 +688,39 @@ xfs_buf_readahead_map(
  * Read an uncached buffer from disk. Allocates and returns a locked
  * buffer containing the disk contents or nothing.
  */
-struct xfs_buf *
+int
 xfs_buf_read_uncached(
 	struct xfs_buftarg	*target,
 	xfs_daddr_t		daddr,
 	size_t			numblks,
 	int			flags,
+	struct xfs_buf		**bpp,
 	const struct xfs_buf_ops *ops)
 {
 	struct xfs_buf		*bp;
 
+	*bpp = NULL;
+
 	bp = xfs_buf_get_uncached(target, numblks, flags);
 	if (!bp)
-		return NULL;
+		return ENOMEM;
 
 	/* set up the buffer for a read IO */
 	ASSERT(bp->b_map_count == 1);
-	bp->b_bn = daddr;
+	bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */
 	bp->b_maps[0].bm_bn = daddr;
 	bp->b_flags |= XBF_READ;
 	bp->b_ops = ops;
 
 	xfs_buf_submit_wait(bp);
-	return bp;
+	if (bp->b_error) {
+		int	error = bp->b_error;
+		xfs_buf_relse(bp);
+		return error;
+	}
+
+	*bpp = bp;
+	return 0;
 }
 
 /*
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 0acfc30..82002c0 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -269,9 +269,9 @@ int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
 
 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
 				int flags);
-struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
-				xfs_daddr_t daddr, size_t numblks, int flags,
-				const struct xfs_buf_ops *ops);
+int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
+			  size_t numblks, int flags, struct xfs_buf **bpp,
+			  const struct xfs_buf_ops *ops);
 void xfs_buf_hold(struct xfs_buf *bp);
 
 /* Releasing Buffers */
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 126b4b3..ece69c2 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -172,16 +172,11 @@ xfs_growfs_data_private(
 	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
 		return error;
 	dpct = pct - mp->m_sb.sb_imax_pct;
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp,
+	error = xfs_buf_read_uncached(mp->m_ddev_targp,
 				XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
-				XFS_FSS_TO_BB(mp, 1), 0, NULL);
-	if (!bp)
-		return -EIO;
-	if (bp->b_error) {
-		error = bp->b_error;
-		xfs_buf_relse(bp);
+				XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error)
 		return error;
-	}
 	xfs_buf_relse(bp);
 
 	new = nb;	/* use new as a temporary here */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 78a2799..2adf6ce 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -300,21 +300,15 @@ xfs_readsb(
 	 * access to the superblock.
 	 */
 reread:
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
-				   BTOBB(sector_size), 0, buf_ops);
-	if (!bp) {
-		if (loud)
-			xfs_warn(mp, "SB buffer read failed");
-		return -EIO;
-	}
-	if (bp->b_error) {
-		error = bp->b_error;
+	error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
+				   BTOBB(sector_size), 0, &bp, buf_ops);
+	if (error) {
 		if (loud)
 			xfs_warn(mp, "SB validate failed with error %d.", error);
 		/* bad CRC means corrupted metadata */
 		if (error == -EFSBADCRC)
 			error = -EFSCORRUPTED;
-		goto release_buf;
+		return error;
 	}
 
 	/*
@@ -366,7 +360,8 @@ reread:
 	return 0;
 
 release_buf:
-	xfs_buf_relse(bp);
+	if (bp)
+		xfs_buf_relse(bp);
 	return error;
 }
 
@@ -544,40 +539,43 @@ xfs_set_inoalignment(xfs_mount_t *mp)
  * Check that the data (and log if separate) is an ok size.
  */
 STATIC int
-xfs_check_sizes(xfs_mount_t *mp)
+xfs_check_sizes(
+	struct xfs_mount *mp)
 {
-	xfs_buf_t	*bp;
+	struct xfs_buf	*bp;
 	xfs_daddr_t	d;
+	int		error;
 
 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
 		xfs_warn(mp, "filesystem size mismatch detected");
 		return -EFBIG;
 	}
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp,
+	error = xfs_buf_read_uncached(mp->m_ddev_targp,
 					d - XFS_FSS_TO_BB(mp, 1),
-					XFS_FSS_TO_BB(mp, 1), 0, NULL);
-	if (!bp) {
+					XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
 		xfs_warn(mp, "last sector read failed");
-		return -EIO;
+		return error;
 	}
 	xfs_buf_relse(bp);
 
-	if (mp->m_logdev_targp != mp->m_ddev_targp) {
-		d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
-		if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
-			xfs_warn(mp, "log size mismatch detected");
-			return -EFBIG;
-		}
-		bp = xfs_buf_read_uncached(mp->m_logdev_targp,
+	if (mp->m_logdev_targp == mp->m_ddev_targp)
+		return 0;
+
+	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
+	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
+		xfs_warn(mp, "log size mismatch detected");
+		return -EFBIG;
+	}
+	error = xfs_buf_read_uncached(mp->m_logdev_targp,
 					d - XFS_FSB_TO_BB(mp, 1),
-					XFS_FSB_TO_BB(mp, 1), 0, NULL);
-		if (!bp) {
-			xfs_warn(mp, "log device read failed");
-			return -EIO;
-		}
-		xfs_buf_relse(bp);
+					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
+		xfs_warn(mp, "log device read failed");
+		return error;
 	}
+	xfs_buf_relse(bp);
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index d45aebe..e1175ea 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -921,16 +921,11 @@ xfs_growfs_rt(
 	/*
 	 * Read in the last block of the device, make sure it exists.
 	 */
-	bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 				XFS_FSB_TO_BB(mp, nrblocks - 1),
-				XFS_FSB_TO_BB(mp, 1), 0, NULL);
-	if (!bp)
-		return -EIO;
-	if (bp->b_error) {
-		error = bp->b_error;
-		xfs_buf_relse(bp);
+				XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error)
 		return error;
-	}
 	xfs_buf_relse(bp);
 
 	/*
@@ -1184,11 +1179,12 @@ xfs_rtallocate_extent(
  */
 int				/* error */
 xfs_rtmount_init(
-	xfs_mount_t	*mp)	/* file system mount structure */
+	struct xfs_mount	*mp)	/* file system mount structure */
 {
-	xfs_buf_t	*bp;	/* buffer for last block of subvolume */
-	xfs_daddr_t	d;	/* address of last block of subvolume */
-	xfs_sb_t	*sbp;	/* filesystem superblock copy in mount */
+	struct xfs_buf		*bp;	/* buffer for last block of subvolume */
+	struct xfs_sb		*sbp;	/* filesystem superblock copy in mount */
+	xfs_daddr_t		d;	/* address of last block of subvolume */
+	int			error;
 
 	sbp = &mp->m_sb;
 	if (sbp->sb_rblocks == 0)
@@ -1214,14 +1210,12 @@ xfs_rtmount_init(
 			(unsigned long long) mp->m_sb.sb_rblocks);
 		return -EFBIG;
 	}
-	bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 					d - XFS_FSB_TO_BB(mp, 1),
-					XFS_FSB_TO_BB(mp, 1), 0, NULL);
-	if (!bp || bp->b_error) {
+					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
 		xfs_warn(mp, "realtime device size check failed");
-		if (bp)
-			xfs_buf_relse(bp);
-		return -EIO;
+		return error;
 	}
 	xfs_buf_relse(bp);
 	return 0;
-- 
2.0.0

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes
  2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
                   ` (9 preceding siblings ...)
  2014-09-25 12:34 ` [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly Dave Chinner
@ 2014-09-25 12:34 ` Dave Chinner
  2014-09-26 10:22   ` Christoph Hellwig
  2014-09-29 19:09   ` Brian Foster
  10 siblings, 2 replies; 27+ messages in thread
From: Dave Chinner @ 2014-09-25 12:34 UTC (permalink / raw)
  To: xfs

From: Christoph Hellwig <hch@infradead.org>

xfs_zero_remaining_bytes() open codes a log of buffer manupulations
to do a read forllowed by a write. It can simply be replaced by an
uncached read followed by a xfs_bwrite() call.

[Christoph, can I get your sign-off for this?]

Signed-off-by: Dave Chinner <david@fromorbit.com>
---
 fs/xfs/xfs_bmap_util.c | 44 ++++++++++++++------------------------------
 1 file changed, 14 insertions(+), 30 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 41d9488..c2aaa58 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -1122,14 +1122,6 @@ xfs_zero_remaining_bytes(
 	if (endoff > XFS_ISIZE(ip))
 		endoff = XFS_ISIZE(ip);
 
-	bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?
-					mp->m_rtdev_targp : mp->m_ddev_targp,
-				  BTOBB(mp->m_sb.sb_blocksize), 0);
-	if (!bp)
-		return -ENOMEM;
-
-	xfs_buf_unlock(bp);
-
 	for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
 		uint lock_mode;
 
@@ -1152,32 +1144,24 @@ xfs_zero_remaining_bytes(
 		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
 		if (imap.br_state == XFS_EXT_UNWRITTEN)
 			continue;
-		XFS_BUF_UNDONE(bp);
-		XFS_BUF_UNWRITE(bp);
-		XFS_BUF_READ(bp);
-		XFS_BUF_SET_ADDR(bp, xfs_fsb_to_db(ip, imap.br_startblock));
 
-		error = xfs_buf_submit_wait(bp);
-		if (error) {
-			xfs_buf_ioerror_alert(bp,
-					"xfs_zero_remaining_bytes(read)");
-			break;
-		}
+		error = xfs_buf_read_uncached(XFS_IS_REALTIME_INODE(ip) ?
+				mp->m_rtdev_targp : mp->m_ddev_targp,
+				xfs_fsb_to_db(ip, imap.br_startblock),
+				BTOBB(mp->m_sb.sb_blocksize),
+				0, &bp, NULL);
+		if (error)
+			return error;
+
 		memset(bp->b_addr +
-			(offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
-		      0, lastoffset - offset + 1);
-		XFS_BUF_UNDONE(bp);
-		XFS_BUF_UNREAD(bp);
-		XFS_BUF_WRITE(bp);
+				(offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
+		       0, lastoffset - offset + 1);
 
-		error = xfs_buf_submit_wait(bp);
-		if (error) {
-			xfs_buf_ioerror_alert(bp,
-					"xfs_zero_remaining_bytes(write)");
-			break;
-		}
+		error = xfs_bwrite(bp);
+		xfs_buf_relse(bp);
+		if (error)
+			return error;
 	}
-	xfs_buf_free(bp);
 	return error;
 }
 
-- 
2.0.0

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* Re: [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code
  2014-09-25 12:34 ` [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code Dave Chinner
@ 2014-09-25 16:19   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-25 16:19 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 03/11] xfs: synchronous buffer IO needs a reference
  2014-09-25 12:34 ` [PATCH 03/11] xfs: synchronous buffer IO needs a reference Dave Chinner
@ 2014-09-26 10:11   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:11 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality
  2014-09-25 12:34 ` [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality Dave Chinner
@ 2014-09-26 10:14   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:14 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling
  2014-09-25 12:34 ` [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling Dave Chinner
@ 2014-09-26 10:15   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:15 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

I still don't understand why we even need b_error on the submission
side, we should be able to just pass the error on the stack.

But we can sort this out later, and the change looks ok, so:

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 07/11] xfs: xfs_bioerror can die.
  2014-09-25 12:34 ` [PATCH 07/11] xfs: xfs_bioerror can die Dave Chinner
@ 2014-09-26 10:16   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:16 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 08/11] xfs: kill xfs_bioerror_relse
  2014-09-25 12:34 ` [PATCH 08/11] xfs: kill xfs_bioerror_relse Dave Chinner
@ 2014-09-26 10:18   ` Christoph Hellwig
  2014-09-29 19:09   ` Brian Foster
  1 sibling, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:18 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly
  2014-09-25 12:34 ` [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly Dave Chinner
@ 2014-09-26 10:21   ` Christoph Hellwig
  2014-09-26 23:20     ` [PATCH 10/11 v2] " Dave Chinner
  0 siblings, 1 reply; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:21 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

On Thu, Sep 25, 2014 at 10:34:20PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> xfs_buf_read_uncached() has two failure modes. If can either return
> NULL or bp->b_error != 0 depending on the type of failure, and not
> all callers check for both. Fix it up.

This changelog still seems to be for your previous version and needs
an update now tha xfs_buf_read_uncached always returns the error
directly.

> -		return NULL;
> +		return ENOMEM;

Should be -ENOMEM these days, shouldn't it?

>  release_buf:
> -	xfs_buf_relse(bp);
> +	if (bp)
> +		xfs_buf_relse(bp);

Shouldn't bp always be valid at this point?

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes
  2014-09-25 12:34 ` [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes Dave Chinner
@ 2014-09-26 10:22   ` Christoph Hellwig
  2014-09-29 19:09   ` Brian Foster
  1 sibling, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:22 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

On Thu, Sep 25, 2014 at 10:34:21PM +1000, Dave Chinner wrote:
> From: Christoph Hellwig <hch@infradead.org>
> 
> xfs_zero_remaining_bytes() open codes a log of buffer manupulations
> to do a read forllowed by a write. It can simply be replaced by an
> uncached read followed by a xfs_bwrite() call.
> 
> [Christoph, can I get your sign-off for this?]

Sure,

Signed-off-by: Christoph Hellwig <hch@lst.de>

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 01/11] xfs: force the log before shutting down
  2014-09-25 12:34 ` [PATCH 01/11] xfs: force the log before shutting down Dave Chinner
@ 2014-09-26 10:37   ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 10:37 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

On Thu, Sep 25, 2014 at 10:34:11PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> When we have marked the filesystem for shutdown, we want to prevent
> any further buffer IO from being submitted. However, we currently
> force the log after marking the filesystem as shut down, hence
> allowing IO to the log *after* we have marked both the filesystem
> and the log as in an error state.
> 
> Clean this up by forcing the log before we mark the filesytem with
> an error. This replaces the pure CIL flush that we currently have
> which works around this same issue (i.e the CIL can't be flushed
> once the shutdown flags are set) and hence enables us to clean up
> the logic substantially.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>


A couple nitpicks:

> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
> index b1131fe..a598955 100644
> --- a/fs/xfs/xfs_log.c
> +++ b/fs/xfs/xfs_log.c
> @@ -3924,13 +3924,14 @@ xfs_log_force_umount(

The top of the function comment speaks about the delaylog case,
given that this is the only option now it might be worth to clean
that up.

>  	retval = 0;

This assignment can be removed now that the xlog_state_ioerror call
below is unconditional.

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^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait]
  2014-09-25 12:34 ` [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait] Dave Chinner
@ 2014-09-26 12:33   ` Christoph Hellwig
  2014-10-01 23:03     ` Dave Chinner
  0 siblings, 1 reply; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-26 12:33 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

Looks good, although I still think this would benefit from a helper
like the one below (patch lightly tested).

Reviewed-by: Christoph Hellwig <hch@lst.de>


diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 0ac54a0..081ccf3 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1287,28 +1287,18 @@ _xfs_buf_ioapply(
 	blk_finish_plug(&plug);
 }
 
-/*
- * Asynchronous IO submission path. This transfers the buffer lock ownership and
- * the current reference to the IO. It is not safe to reference the buffer after
- * a call to this function unless the caller holds an additional reference
- * itself.
- */
-void
-xfs_buf_submit(
+static int
+__xfs_buf_submit(
 	struct xfs_buf	*bp)
 {
-	trace_xfs_buf_submit(bp, _RET_IP_);
-
 	ASSERT(!(bp->b_flags & _XBF_DELWRI_Q));
-	ASSERT(bp->b_flags & XBF_ASYNC);
 
 	/* on shutdown we stale and complete the buffer immediately */
 	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
 		xfs_buf_ioerror(bp, -EIO);
 		bp->b_flags &= ~XBF_DONE;
 		xfs_buf_stale(bp);
-		xfs_buf_ioend(bp);
-		return;
+		return -EIO;
 	}
 
 	if (bp->b_flags & XBF_WRITE)
@@ -1318,12 +1308,8 @@ xfs_buf_submit(
 	bp->b_io_error = 0;
 
 	/*
-	 * The caller's reference is released during I/O completion.
-	 * This occurs some time after the last b_io_remaining reference is
-	 * released, so after we drop our Io reference we have to have some
-	 * other reference to ensure the buffer doesn't go away from underneath
-	 * us. Take a direct reference to ensure we have safe access to the
-	 * buffer until we are finished with it.
+	 * Take a reference to ensure we have safe access to the buffer until
+	 * we are finished with it.
 	 */
 	xfs_buf_hold(bp);
 
@@ -1341,64 +1327,56 @@ xfs_buf_submit(
 	 * that we don't return to the caller with completion still pending.
 	 */
 	if (atomic_dec_and_test(&bp->b_io_remaining) == 1) {
-		if (bp->b_error)
-			xfs_buf_ioend(bp);
-		else
+		if ((bp->b_flags & XBF_ASYNC) && !bp->b_error)
 			xfs_buf_ioend_async(bp);
+		else
+			xfs_buf_ioend(bp);
 	}
 
-	xfs_buf_rele(bp);
-	/* Note: it is not safe to reference bp now we've dropped our ref */
+	return 0;
 }
 
 /*
- * Synchronous buffer IO submission path, read or write.
+ * Asynchronous IO submission path. This transfers the buffer lock ownership and
+ * the current reference to the IO. It is not safe to reference the buffer after
+ * a call to this function unless the caller holds an additional reference
+ * itself.
  */
-int
-xfs_buf_submit_wait(
+void
+xfs_buf_submit(
 	struct xfs_buf	*bp)
 {
 	int		error;
 
-	trace_xfs_buf_submit_wait(bp, _RET_IP_);
+	trace_xfs_buf_submit(bp, _RET_IP_);
 
-	ASSERT(!(bp->b_flags & (_XBF_DELWRI_Q | XBF_ASYNC)));
+	ASSERT(bp->b_flags & XBF_ASYNC);
 
-	if (XFS_FORCED_SHUTDOWN(bp->b_target->bt_mount)) {
-		xfs_buf_ioerror(bp, -EIO);
-		xfs_buf_stale(bp);
-		bp->b_flags &= ~XBF_DONE;
-		return -EIO;
-	}
+	error = __xfs_buf_submit(bp);
+	if (error)
+		xfs_buf_ioend(bp);
+	else
+		xfs_buf_rele(bp);
 
-	if (bp->b_flags & XBF_WRITE)
-		xfs_buf_wait_unpin(bp);
+	/* Note: it is not safe to reference bp now we've dropped our ref */
+}
 
-	/* clear the internal error state to avoid spurious errors */
-	bp->b_io_error = 0;
+/*
+ * Synchronous buffer IO submission path, read or write.
+ */
+int
+xfs_buf_submit_wait(
+	struct xfs_buf	*bp)
+{
+	int		error;
 
-	/*
-	 * For synchronous IO, the IO does not inherit the submitters reference
-	 * count, nor the buffer lock. Hence we cannot release the reference we
-	 * are about to take until we've waited for all IO completion to occur,
-	 * including any xfs_buf_ioend_async() work that may be pending.
-	 */
-	xfs_buf_hold(bp);
+	trace_xfs_buf_submit_wait(bp, _RET_IP_);
 
-	/*
-	 * Set the count to 1 initially, this will stop an I/O completion
-	 * callout which happens before we have started all the I/O from calling
-	 * xfs_buf_ioend too early.
-	 */
-	atomic_set(&bp->b_io_remaining, 1);
-	_xfs_buf_ioapply(bp);
+	ASSERT(!(bp->b_flags & XBF_ASYNC));
 
-	/*
-	 * make sure we run completion synchronously if it raced with us and is
-	 * already complete.
-	 */
-	if (atomic_dec_and_test(&bp->b_io_remaining) == 1)
-		xfs_buf_ioend(bp);
+	error = __xfs_buf_submit(bp);
+	if (error)
+		return error;
 
 	/* wait for completion before gathering the error from the buffer */
 	trace_xfs_buf_iowait(bp, _RET_IP_);

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* [PATCH 10/11 v2] xfs: check xfs_buf_read_uncached returns correctly
  2014-09-26 10:21   ` Christoph Hellwig
@ 2014-09-26 23:20     ` Dave Chinner
  2014-09-29 10:40       ` Christoph Hellwig
  0 siblings, 1 reply; 27+ messages in thread
From: Dave Chinner @ 2014-09-26 23:20 UTC (permalink / raw)
  To: Christoph Hellwig; +Cc: xfs

On Fri, Sep 26, 2014 at 03:21:48AM -0700, Christoph Hellwig wrote:
> On Thu, Sep 25, 2014 at 10:34:20PM +1000, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > xfs_buf_read_uncached() has two failure modes. If can either return
> > NULL or bp->b_error != 0 depending on the type of failure, and not
> > all callers check for both. Fix it up.
> 
> This changelog still seems to be for your previous version and needs
> an update now tha xfs_buf_read_uncached always returns the error
> directly.

Fixed.

> 
> > -		return NULL;
> > +		return ENOMEM;
> 
> Should be -ENOMEM these days, shouldn't it?

Yes, good catch.

> >  release_buf:
> > -	xfs_buf_relse(bp);
> > +	if (bp)
> > +		xfs_buf_relse(bp);
> 
> Shouldn't bp always be valid at this point?

It is. Fixed.

Updated patch below.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

xfs: check xfs_buf_read_uncached returns correctly

From: Dave Chinner <dchinner@redhat.com>

xfs_buf_read_uncached() has two failure modes. If can either return
NULL or bp->b_error != 0 depending on the type of failure, and not
all callers check for both. Fix it so that xfs_buf_read_uncached()
always returns the error status, and the buffer is returned as a
function parameter. The buffer will only be returned on success.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/xfs_buf.c     | 18 +++++++++++++----
 fs/xfs/xfs_buf.h     |  6 +++---
 fs/xfs/xfs_fsops.c   | 11 +++--------
 fs/xfs/xfs_mount.c   | 55 +++++++++++++++++++++++++---------------------------
 fs/xfs/xfs_rtalloc.c | 30 ++++++++++++----------------
 5 files changed, 58 insertions(+), 62 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index d1d3fe6..017b6af 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -688,29 +688,39 @@ xfs_buf_readahead_map(
  * Read an uncached buffer from disk. Allocates and returns a locked
  * buffer containing the disk contents or nothing.
  */
-struct xfs_buf *
+int
 xfs_buf_read_uncached(
 	struct xfs_buftarg	*target,
 	xfs_daddr_t		daddr,
 	size_t			numblks,
 	int			flags,
+	struct xfs_buf		**bpp,
 	const struct xfs_buf_ops *ops)
 {
 	struct xfs_buf		*bp;
 
+	*bpp = NULL;
+
 	bp = xfs_buf_get_uncached(target, numblks, flags);
 	if (!bp)
-		return NULL;
+		return -ENOMEM;
 
 	/* set up the buffer for a read IO */
 	ASSERT(bp->b_map_count == 1);
-	bp->b_bn = daddr;
+	bp->b_bn = XFS_BUF_DADDR_NULL;  /* always null for uncached buffers */
 	bp->b_maps[0].bm_bn = daddr;
 	bp->b_flags |= XBF_READ;
 	bp->b_ops = ops;
 
 	xfs_buf_submit_wait(bp);
-	return bp;
+	if (bp->b_error) {
+		int	error = bp->b_error;
+		xfs_buf_relse(bp);
+		return error;
+	}
+
+	*bpp = bp;
+	return 0;
 }
 
 /*
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 0acfc30..82002c0 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -269,9 +269,9 @@ int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);
 
 struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
 				int flags);
-struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
-				xfs_daddr_t daddr, size_t numblks, int flags,
-				const struct xfs_buf_ops *ops);
+int xfs_buf_read_uncached(struct xfs_buftarg *target, xfs_daddr_t daddr,
+			  size_t numblks, int flags, struct xfs_buf **bpp,
+			  const struct xfs_buf_ops *ops);
 void xfs_buf_hold(struct xfs_buf *bp);
 
 /* Releasing Buffers */
diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c
index 126b4b3..ece69c2 100644
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -172,16 +172,11 @@ xfs_growfs_data_private(
 	if ((error = xfs_sb_validate_fsb_count(&mp->m_sb, nb)))
 		return error;
 	dpct = pct - mp->m_sb.sb_imax_pct;
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp,
+	error = xfs_buf_read_uncached(mp->m_ddev_targp,
 				XFS_FSB_TO_BB(mp, nb) - XFS_FSS_TO_BB(mp, 1),
-				XFS_FSS_TO_BB(mp, 1), 0, NULL);
-	if (!bp)
-		return -EIO;
-	if (bp->b_error) {
-		error = bp->b_error;
-		xfs_buf_relse(bp);
+				XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error)
 		return error;
-	}
 	xfs_buf_relse(bp);
 
 	new = nb;	/* use new as a temporary here */
diff --git a/fs/xfs/xfs_mount.c b/fs/xfs/xfs_mount.c
index 78a2799..d731035 100644
--- a/fs/xfs/xfs_mount.c
+++ b/fs/xfs/xfs_mount.c
@@ -300,21 +300,15 @@ xfs_readsb(
 	 * access to the superblock.
 	 */
 reread:
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
-				   BTOBB(sector_size), 0, buf_ops);
-	if (!bp) {
-		if (loud)
-			xfs_warn(mp, "SB buffer read failed");
-		return -EIO;
-	}
-	if (bp->b_error) {
-		error = bp->b_error;
+	error = xfs_buf_read_uncached(mp->m_ddev_targp, XFS_SB_DADDR,
+				   BTOBB(sector_size), 0, &bp, buf_ops);
+	if (error) {
 		if (loud)
 			xfs_warn(mp, "SB validate failed with error %d.", error);
 		/* bad CRC means corrupted metadata */
 		if (error == -EFSBADCRC)
 			error = -EFSCORRUPTED;
-		goto release_buf;
+		return error;
 	}
 
 	/*
@@ -544,40 +538,43 @@ xfs_set_inoalignment(xfs_mount_t *mp)
  * Check that the data (and log if separate) is an ok size.
  */
 STATIC int
-xfs_check_sizes(xfs_mount_t *mp)
+xfs_check_sizes(
+	struct xfs_mount *mp)
 {
-	xfs_buf_t	*bp;
+	struct xfs_buf	*bp;
 	xfs_daddr_t	d;
+	int		error;
 
 	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks);
 	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_dblocks) {
 		xfs_warn(mp, "filesystem size mismatch detected");
 		return -EFBIG;
 	}
-	bp = xfs_buf_read_uncached(mp->m_ddev_targp,
+	error = xfs_buf_read_uncached(mp->m_ddev_targp,
 					d - XFS_FSS_TO_BB(mp, 1),
-					XFS_FSS_TO_BB(mp, 1), 0, NULL);
-	if (!bp) {
+					XFS_FSS_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
 		xfs_warn(mp, "last sector read failed");
-		return -EIO;
+		return error;
 	}
 	xfs_buf_relse(bp);
 
-	if (mp->m_logdev_targp != mp->m_ddev_targp) {
-		d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
-		if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
-			xfs_warn(mp, "log size mismatch detected");
-			return -EFBIG;
-		}
-		bp = xfs_buf_read_uncached(mp->m_logdev_targp,
+	if (mp->m_logdev_targp == mp->m_ddev_targp)
+		return 0;
+
+	d = (xfs_daddr_t)XFS_FSB_TO_BB(mp, mp->m_sb.sb_logblocks);
+	if (XFS_BB_TO_FSB(mp, d) != mp->m_sb.sb_logblocks) {
+		xfs_warn(mp, "log size mismatch detected");
+		return -EFBIG;
+	}
+	error = xfs_buf_read_uncached(mp->m_logdev_targp,
 					d - XFS_FSB_TO_BB(mp, 1),
-					XFS_FSB_TO_BB(mp, 1), 0, NULL);
-		if (!bp) {
-			xfs_warn(mp, "log device read failed");
-			return -EIO;
-		}
-		xfs_buf_relse(bp);
+					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
+		xfs_warn(mp, "log device read failed");
+		return error;
 	}
+	xfs_buf_relse(bp);
 	return 0;
 }
 
diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c
index d45aebe..e1175ea 100644
--- a/fs/xfs/xfs_rtalloc.c
+++ b/fs/xfs/xfs_rtalloc.c
@@ -921,16 +921,11 @@ xfs_growfs_rt(
 	/*
 	 * Read in the last block of the device, make sure it exists.
 	 */
-	bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 				XFS_FSB_TO_BB(mp, nrblocks - 1),
-				XFS_FSB_TO_BB(mp, 1), 0, NULL);
-	if (!bp)
-		return -EIO;
-	if (bp->b_error) {
-		error = bp->b_error;
-		xfs_buf_relse(bp);
+				XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error)
 		return error;
-	}
 	xfs_buf_relse(bp);
 
 	/*
@@ -1184,11 +1179,12 @@ xfs_rtallocate_extent(
  */
 int				/* error */
 xfs_rtmount_init(
-	xfs_mount_t	*mp)	/* file system mount structure */
+	struct xfs_mount	*mp)	/* file system mount structure */
 {
-	xfs_buf_t	*bp;	/* buffer for last block of subvolume */
-	xfs_daddr_t	d;	/* address of last block of subvolume */
-	xfs_sb_t	*sbp;	/* filesystem superblock copy in mount */
+	struct xfs_buf		*bp;	/* buffer for last block of subvolume */
+	struct xfs_sb		*sbp;	/* filesystem superblock copy in mount */
+	xfs_daddr_t		d;	/* address of last block of subvolume */
+	int			error;
 
 	sbp = &mp->m_sb;
 	if (sbp->sb_rblocks == 0)
@@ -1214,14 +1210,12 @@ xfs_rtmount_init(
 			(unsigned long long) mp->m_sb.sb_rblocks);
 		return -EFBIG;
 	}
-	bp = xfs_buf_read_uncached(mp->m_rtdev_targp,
+	error = xfs_buf_read_uncached(mp->m_rtdev_targp,
 					d - XFS_FSB_TO_BB(mp, 1),
-					XFS_FSB_TO_BB(mp, 1), 0, NULL);
-	if (!bp || bp->b_error) {
+					XFS_FSB_TO_BB(mp, 1), 0, &bp, NULL);
+	if (error) {
 		xfs_warn(mp, "realtime device size check failed");
-		if (bp)
-			xfs_buf_relse(bp);
-		return -EIO;
+		return error;
 	}
 	xfs_buf_relse(bp);
 	return 0;

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^ permalink raw reply related	[flat|nested] 27+ messages in thread
* Re: [PATCH 10/11 v2] xfs: check xfs_buf_read_uncached returns correctly
  2014-09-26 23:20     ` [PATCH 10/11 v2] " Dave Chinner
@ 2014-09-29 10:40       ` Christoph Hellwig
  0 siblings, 0 replies; 27+ messages in thread
From: Christoph Hellwig @ 2014-09-29 10:40 UTC (permalink / raw)
  To: Dave Chinner; +Cc: Christoph Hellwig, xfs

> Updated patch below.

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 08/11] xfs: kill xfs_bioerror_relse
  2014-09-25 12:34 ` [PATCH 08/11] xfs: kill xfs_bioerror_relse Dave Chinner
  2014-09-26 10:18   ` Christoph Hellwig
@ 2014-09-29 19:09   ` Brian Foster
  1 sibling, 0 replies; 27+ messages in thread
From: Brian Foster @ 2014-09-29 19:09 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

On Thu, Sep 25, 2014 at 10:34:18PM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> There is only one caller now - xfs_trans_read_buf_map() - and it has
> very well defined call semantics - read, synchronous, and b_iodone
> is NULL. Hence it's pretty clear what error handling is necessary
> for this case. The bigger problem of untangling
> xfs_trans_read_buf_map error handling is left to a future patch.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/xfs_buf.c       | 39 ---------------------------------------
>  fs/xfs/xfs_buf.h       |  2 --
>  fs/xfs/xfs_trans_buf.c |  9 ++++++---
>  3 files changed, 6 insertions(+), 44 deletions(-)
> 
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index cc6a558..4696ff5 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1074,45 +1074,6 @@ xfs_buf_ioerror_alert(
>  		(__uint64_t)XFS_BUF_ADDR(bp), func, -bp->b_error, bp->b_length);
>  }
>  
> -/*
> - * Same as xfs_bioerror, except that we are releasing the buffer
> - * here ourselves, and avoiding the xfs_buf_ioend call.
> - * This is meant for userdata errors; metadata bufs come with
> - * iodone functions attached, so that we can track down errors.
> - */
> -int
> -xfs_bioerror_relse(
> -	struct xfs_buf	*bp)
> -{
> -	int64_t		fl = bp->b_flags;
> -	/*
> -	 * No need to wait until the buffer is unpinned.
> -	 * We aren't flushing it.
> -	 *
> -	 * chunkhold expects B_DONE to be set, whether
> -	 * we actually finish the I/O or not. We don't want to
> -	 * change that interface.
> -	 */
> -	XFS_BUF_UNREAD(bp);
> -	XFS_BUF_DONE(bp);
> -	xfs_buf_stale(bp);
> -	bp->b_iodone = NULL;
> -	if (!(fl & XBF_ASYNC)) {
> -		/*
> -		 * Mark b_error and B_ERROR _both_.
> -		 * Lot's of chunkcache code assumes that.
> -		 * There's no reason to mark error for
> -		 * ASYNC buffers.
> -		 */
> -		xfs_buf_ioerror(bp, -EIO);
> -		complete(&bp->b_iowait);
> -	} else {
> -		xfs_buf_relse(bp);
> -	}
> -
> -	return -EIO;
> -}
> -
>  int
>  xfs_bwrite(
>  	struct xfs_buf		*bp)
> diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
> index 44db8cd..d8f57f6 100644
> --- a/fs/xfs/xfs_buf.h
> +++ b/fs/xfs/xfs_buf.h
> @@ -297,8 +297,6 @@ extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
>  #define xfs_buf_zero(bp, off, len) \
>  	    xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
>  
> -extern int xfs_bioerror_relse(struct xfs_buf *);
> -
>  /* Buffer Utility Routines */
>  extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
>  
> diff --git a/fs/xfs/xfs_trans_buf.c b/fs/xfs/xfs_trans_buf.c
> index 96c898e..db4be5b 100644
> --- a/fs/xfs/xfs_trans_buf.c
> +++ b/fs/xfs/xfs_trans_buf.c
> @@ -324,11 +324,14 @@ xfs_trans_read_buf_map(
>  			 */
>  			if (XFS_FORCED_SHUTDOWN(mp)) {
>  				trace_xfs_bdstrat_shut(bp, _RET_IP_);
> -				xfs_bioerror_relse(bp);
> -			} else {
> -				xfs_buf_iorequest(bp);
> +				bp->b_flags &= ~(XBF_READ | XBF_DONE);
> +				xfs_buf_ioerror(bp, -EIO);
> +				xfs_buf_stale(bp);
> +				xfs_buf_relse(bp);

Where does the xfs_buf_relse() come from in this particular scenario?
Shouldn't the bp still remain locked/reffed against the transaction?

Brian

P.S., I realized it doesn't matter too much because this whole block
goes away in the subsequent patch.

> +				return -EIO;
>  			}
>  
> +			xfs_buf_iorequest(bp);
>  			error = xfs_buf_iowait(bp);
>  			if (error) {
>  				xfs_buf_ioerror_alert(bp, __func__);
> -- 
> 2.0.0
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs

_______________________________________________
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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes
  2014-09-25 12:34 ` [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes Dave Chinner
  2014-09-26 10:22   ` Christoph Hellwig
@ 2014-09-29 19:09   ` Brian Foster
  1 sibling, 0 replies; 27+ messages in thread
From: Brian Foster @ 2014-09-29 19:09 UTC (permalink / raw)
  To: Dave Chinner; +Cc: xfs

On Thu, Sep 25, 2014 at 10:34:21PM +1000, Dave Chinner wrote:
> From: Christoph Hellwig <hch@infradead.org>
> 
> xfs_zero_remaining_bytes() open codes a log of buffer manupulations
					  lot
> to do a read forllowed by a write. It can simply be replaced by an
	       followed
> uncached read followed by a xfs_bwrite() call.
			    an
> 
> [Christoph, can I get your sign-off for this?]
> 
> Signed-off-by: Dave Chinner <david@fromorbit.com>
> ---

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  fs/xfs/xfs_bmap_util.c | 44 ++++++++++++++------------------------------
>  1 file changed, 14 insertions(+), 30 deletions(-)
> 
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index 41d9488..c2aaa58 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -1122,14 +1122,6 @@ xfs_zero_remaining_bytes(
>  	if (endoff > XFS_ISIZE(ip))
>  		endoff = XFS_ISIZE(ip);
>  
> -	bp = xfs_buf_get_uncached(XFS_IS_REALTIME_INODE(ip) ?
> -					mp->m_rtdev_targp : mp->m_ddev_targp,
> -				  BTOBB(mp->m_sb.sb_blocksize), 0);
> -	if (!bp)
> -		return -ENOMEM;
> -
> -	xfs_buf_unlock(bp);
> -
>  	for (offset = startoff; offset <= endoff; offset = lastoffset + 1) {
>  		uint lock_mode;
>  
> @@ -1152,32 +1144,24 @@ xfs_zero_remaining_bytes(
>  		ASSERT(imap.br_startblock != DELAYSTARTBLOCK);
>  		if (imap.br_state == XFS_EXT_UNWRITTEN)
>  			continue;
> -		XFS_BUF_UNDONE(bp);
> -		XFS_BUF_UNWRITE(bp);
> -		XFS_BUF_READ(bp);
> -		XFS_BUF_SET_ADDR(bp, xfs_fsb_to_db(ip, imap.br_startblock));
>  
> -		error = xfs_buf_submit_wait(bp);
> -		if (error) {
> -			xfs_buf_ioerror_alert(bp,
> -					"xfs_zero_remaining_bytes(read)");
> -			break;
> -		}
> +		error = xfs_buf_read_uncached(XFS_IS_REALTIME_INODE(ip) ?
> +				mp->m_rtdev_targp : mp->m_ddev_targp,
> +				xfs_fsb_to_db(ip, imap.br_startblock),
> +				BTOBB(mp->m_sb.sb_blocksize),
> +				0, &bp, NULL);
> +		if (error)
> +			return error;
> +
>  		memset(bp->b_addr +
> -			(offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
> -		      0, lastoffset - offset + 1);
> -		XFS_BUF_UNDONE(bp);
> -		XFS_BUF_UNREAD(bp);
> -		XFS_BUF_WRITE(bp);
> +				(offset - XFS_FSB_TO_B(mp, imap.br_startoff)),
> +		       0, lastoffset - offset + 1);
>  
> -		error = xfs_buf_submit_wait(bp);
> -		if (error) {
> -			xfs_buf_ioerror_alert(bp,
> -					"xfs_zero_remaining_bytes(write)");
> -			break;
> -		}
> +		error = xfs_bwrite(bp);
> +		xfs_buf_relse(bp);
> +		if (error)
> +			return error;
>  	}
> -	xfs_buf_free(bp);
>  	return error;
>  }
>  
> -- 
> 2.0.0
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs

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http://oss.sgi.com/mailman/listinfo/xfs

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait]
  2014-09-26 12:33   ` Christoph Hellwig
@ 2014-10-01 23:03     ` Dave Chinner
  0 siblings, 0 replies; 27+ messages in thread
From: Dave Chinner @ 2014-10-01 23:03 UTC (permalink / raw)
  To: Christoph Hellwig; +Cc: xfs

On Fri, Sep 26, 2014 at 05:33:38AM -0700, Christoph Hellwig wrote:
> Looks good, although I still think this would benefit from a helper
> like the one below (patch lightly tested).
> 
> Reviewed-by: Christoph Hellwig <hch@lst.de>

Thanks. I'll queue the helper patch up for after the next merge
window.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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^ permalink raw reply	[flat|nested] 27+ messages in thread
end of thread, other threads:[~2014-10-01 23:04 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-09-25 12:34 [PATCH 00/11 v2] xfs: clean up xfs_buf io interfaces Dave Chinner
2014-09-25 12:34 ` [PATCH 01/11] xfs: force the log before shutting down Dave Chinner
2014-09-26 10:37   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 02/11] xfs: Don't use xfs_buf_iowait in the delwri buffer code Dave Chinner
2014-09-25 16:19   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 03/11] xfs: synchronous buffer IO needs a reference Dave Chinner
2014-09-26 10:11   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 04/11] xfs: xfs_buf_ioend and xfs_buf_iodone_work duplicate functionality Dave Chinner
2014-09-26 10:14   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 05/11] xfs: rework xfs_buf_bio_endio error handling Dave Chinner
2014-09-26 10:15   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 06/11] xfs: kill xfs_bdstrat_cb Dave Chinner
2014-09-25 12:34 ` [PATCH 07/11] xfs: xfs_bioerror can die Dave Chinner
2014-09-26 10:16   ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 08/11] xfs: kill xfs_bioerror_relse Dave Chinner
2014-09-26 10:18   ` Christoph Hellwig
2014-09-29 19:09   ` Brian Foster
2014-09-25 12:34 ` [PATCH 09/11] xfs: introduce xfs_buf_submit[_wait] Dave Chinner
2014-09-26 12:33   ` Christoph Hellwig
2014-10-01 23:03     ` Dave Chinner
2014-09-25 12:34 ` [PATCH 10/11] xfs: check xfs_buf_read_uncached returns correctly Dave Chinner
2014-09-26 10:21   ` Christoph Hellwig
2014-09-26 23:20     ` [PATCH 10/11 v2] " Dave Chinner
2014-09-29 10:40       ` Christoph Hellwig
2014-09-25 12:34 ` [PATCH 11/11] xfs: simplify xfs_zero_remaining_bytes Dave Chinner
2014-09-26 10:22   ` Christoph Hellwig
2014-09-29 19:09   ` Brian Foster

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