From 288699fecaffa1ef8f75f92020cbb593a772e487 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Wed, 23 Jun 2010 18:11:15 +1000
Subject: xfs: drop dmapi hooks

Dmapi support was never merged upstream, but we still have a lot of hooks
bloating XFS for it, all over the fast pathes of the filesystem.

This patch drops over 700 lines of dmapi overhead.  If we'll ever get HSM
support in mainline at least the namespace events can be done much saner
in the VFS instead of the individual filesystem, so it's not like this
is much help for future work.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 1 -
 1 file changed, 1 deletion(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 34640d6dbdcb..4cd5e00f0c5c 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -23,7 +23,6 @@
 #include "xfs_ag.h"
 #include "xfs_dir2.h"
 #include "xfs_trans.h"
-#include "xfs_dmapi.h"
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
 #include "xfs_alloc_btree.h"
-- 
cgit v1.2.3


From 3400777ff03a3cd4fdbc6cb15676fc7e7ceefc00 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Wed, 23 Jun 2010 18:11:15 +1000
Subject: xfs: remove unneeded #include statements

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <david@fromorbit.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 6 ------
 1 file changed, 6 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 4cd5e00f0c5c..e42c0ba6688a 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -21,18 +21,12 @@
 #include "xfs_inum.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
-#include "xfs_dir2.h"
 #include "xfs_trans.h"
 #include "xfs_mount.h"
 #include "xfs_bmap_btree.h"
-#include "xfs_alloc_btree.h"
-#include "xfs_ialloc_btree.h"
-#include "xfs_dir2_sf.h"
-#include "xfs_attr_sf.h"
 #include "xfs_dinode.h"
 #include "xfs_inode.h"
 #include "xfs_alloc.h"
-#include "xfs_btree.h"
 #include "xfs_error.h"
 #include "xfs_rw.h"
 #include "xfs_iomap.h"
-- 
cgit v1.2.3


From b4e9181e772b0c8b9038c5822ead368b96c2b533 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Wed, 23 Jun 2010 18:11:15 +1000
Subject: xfs: remove unused delta tracking code in xfs_bmapi

This code was introduced four years ago in commit
3e57ecf640428c01ba1ed8c8fc538447ada1715b without any review and has
been unused since.  Remove it just as the rest of the code introduced
in that commit to reduce that stack usage and complexity in this central
piece of code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index e42c0ba6688a..b25d11a3d84e 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -974,7 +974,7 @@ xfs_aops_discard_page(
 		 */
 		error = xfs_bmapi(NULL, ip, offset_fsb, 1,
 				XFS_BMAPI_ENTIRE,  NULL, 0, &imap,
-				&nimaps, NULL, NULL);
+				&nimaps, NULL);
 
 		if (error) {
 			/* something screwed, just bail */
@@ -1002,7 +1002,7 @@ xfs_aops_discard_page(
 		 */
 		xfs_bmap_init(&flist, &firstblock);
 		error = xfs_bunmapi(NULL, ip, offset_fsb, 1, 0, 1, &firstblock,
-					&flist, NULL, &done);
+					&flist, &done);
 
 		ASSERT(!flist.xbf_count && !flist.xbf_first);
 		if (error) {
-- 
cgit v1.2.3


From 3d9b02e3c76531687ab5314e0edf266256f13c2d Mon Sep 17 00:00:00 2001
From: Eric Sandeen <sandeen@sandeen.net>
Date: Thu, 24 Jun 2010 09:45:30 +1000
Subject: xfs: fix corruption case for block size < page size

xfstests 194 first truncats a file back and then extends it again by
truncating it to a larger size.  This causes discard_buffer to drop
the mapped, but not the uptodate bit and thus creates something that
xfs_page_state_convert takes for unmapped space created by mmap because
it doesn't check for the dirty bit, which also gets cleared by
discard_buffer and checked by other ->writepage implementations like
block_write_full_page.  Handle this kind of buffers early, and unlike
Eric's first version of the patch simply ASSERT that the buffers is
dirty, given that the mmap write case can't happen anymore since the
introduction of ->page_mkwrite.  The now dead code dealing with that
will be deleted in a follow on patch.

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index b25d11a3d84e..bd5e1cf5428d 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1125,6 +1125,16 @@ xfs_page_state_convert(
 			continue;
 		}
 
+		/*
+		 * A hole may still be marked uptodate because discard_buffer
+		 * leaves the flag set.
+		 */
+		if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
+			ASSERT(!buffer_dirty(bh));
+			imap_valid = 0;
+			continue;
+		}
+
 		if (imap_valid)
 			imap_valid = xfs_imap_valid(inode, &imap, offset);
 
-- 
cgit v1.2.3


From 89f3b363967a958e756a549c8747c1fb9c930c1a Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Thu, 24 Jun 2010 09:45:48 +1000
Subject: xfs: simplify xfs_vm_releasepage

Currently the xfs releasepage implementation has code to deal with converting
delayed allocated and unwritten space.  But we never get called for those as
we always convert delayed and unwritten space when cleaning a page, or drop
the state from the buffers in block_invalidatepage.  We still keep a WARN_ON
on those cases for now, but remove all the case dealing with it, which allows
to fold xfs_page_state_convert into xfs_vm_writepage and remove the !startio
case from the whole writeback path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 354 +++++++++++++-------------------------------
 1 file changed, 107 insertions(+), 247 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index bd5e1cf5428d..7744a3b630e0 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -754,7 +754,6 @@ xfs_convert_page(
 	struct xfs_bmbt_irec	*imap,
 	xfs_ioend_t		**ioendp,
 	struct writeback_control *wbc,
-	int			startio,
 	int			all_bh)
 {
 	struct buffer_head	*bh, *head;
@@ -825,19 +824,14 @@ xfs_convert_page(
 			ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
 
 			xfs_map_at_offset(inode, bh, imap, offset);
-			if (startio) {
-				xfs_add_to_ioend(inode, bh, offset,
-						type, ioendp, done);
-			} else {
-				set_buffer_dirty(bh);
-				unlock_buffer(bh);
-				mark_buffer_dirty(bh);
-			}
+			xfs_add_to_ioend(inode, bh, offset, type,
+					 ioendp, done);
+
 			page_dirty--;
 			count++;
 		} else {
 			type = IO_NEW;
-			if (buffer_mapped(bh) && all_bh && startio) {
+			if (buffer_mapped(bh) && all_bh) {
 				lock_buffer(bh);
 				xfs_add_to_ioend(inode, bh, offset,
 						type, ioendp, done);
@@ -852,14 +846,12 @@ xfs_convert_page(
 	if (uptodate && bh == head)
 		SetPageUptodate(page);
 
-	if (startio) {
-		if (count) {
-			wbc->nr_to_write--;
-			if (wbc->nr_to_write <= 0)
-				done = 1;
-		}
-		xfs_start_page_writeback(page, !page_dirty, count);
+	if (count) {
+		wbc->nr_to_write--;
+		if (wbc->nr_to_write <= 0)
+			done = 1;
 	}
+	xfs_start_page_writeback(page, !page_dirty, count);
 
 	return done;
  fail_unlock_page:
@@ -879,7 +871,6 @@ xfs_cluster_write(
 	struct xfs_bmbt_irec	*imap,
 	xfs_ioend_t		**ioendp,
 	struct writeback_control *wbc,
-	int			startio,
 	int			all_bh,
 	pgoff_t			tlast)
 {
@@ -895,7 +886,7 @@ xfs_cluster_write(
 
 		for (i = 0; i < pagevec_count(&pvec); i++) {
 			done = xfs_convert_page(inode, pvec.pages[i], tindex++,
-					imap, ioendp, wbc, startio, all_bh);
+					imap, ioendp, wbc, all_bh);
 			if (done)
 				break;
 		}
@@ -1025,51 +1016,94 @@ out_invalidate:
 }
 
 /*
- * Calling this without startio set means we are being asked to make a dirty
- * page ready for freeing it's buffers.  When called with startio set then
- * we are coming from writepage.
+ * Write out a dirty page.
+ *
+ * For delalloc space on the page we need to allocate space and flush it.
+ * For unwritten space on the page we need to start the conversion to
+ * regular allocated space.
+ * For unmapped buffer heads on the page we should allocate space if the
+ * page is uptodate.
+ * For any other dirty buffer heads on the page we should flush them.
  *
- * When called with startio set it is important that we write the WHOLE
- * page if possible.
- * The bh->b_state's cannot know if any of the blocks or which block for
- * that matter are dirty due to mmap writes, and therefore bh uptodate is
- * only valid if the page itself isn't completely uptodate.  Some layers
- * may clear the page dirty flag prior to calling write page, under the
- * assumption the entire page will be written out; by not writing out the
- * whole page the page can be reused before all valid dirty data is
- * written out.  Note: in the case of a page that has been dirty'd by
- * mapwrite and but partially setup by block_prepare_write the
- * bh->b_states's will not agree and only ones setup by BPW/BCW will have
- * valid state, thus the whole page must be written out thing.
+ * If we detect that a transaction would be required to flush the page, we
+ * have to check the process flags first, if we are already in a transaction
+ * or disk I/O during allocations is off, we need to fail the writepage and
+ * redirty the page.
+ *
+ * The bh->b_state's cannot know if any of the blocks or which block for that
+ * matter are dirty due to mmap writes, and therefore bh uptodate is only
+ * valid if the page itself isn't completely uptodate.
  */
-
 STATIC int
-xfs_page_state_convert(
-	struct inode	*inode,
-	struct page	*page,
-	struct writeback_control *wbc,
-	int		startio,
-	int		unmapped) /* also implies page uptodate */
+xfs_vm_writepage(
+	struct page		*page,
+	struct writeback_control *wbc)
 {
+	struct inode		*inode = page->mapping->host;
+	int			need_trans;
+	int			delalloc, unmapped, unwritten;
 	struct buffer_head	*bh, *head;
 	struct xfs_bmbt_irec	imap;
 	xfs_ioend_t		*ioend = NULL, *iohead = NULL;
 	loff_t			offset;
-	unsigned long           p_offset = 0;
 	unsigned int		type;
 	__uint64_t              end_offset;
 	pgoff_t                 end_index, last_index;
 	ssize_t			size, len;
 	int			flags, err, imap_valid = 0, uptodate = 1;
-	int			page_dirty, count = 0;
-	int			trylock = 0;
-	int			all_bh = unmapped;
+	int			count = 0;
+	int			all_bh;
+
+	trace_xfs_writepage(inode, page, 0);
+
+	/*
+	 * Refuse to write the page out if we are called from reclaim context.
+	 *
+	 * This is primarily to avoid stack overflows when called from deep
+	 * used stacks in random callers for direct reclaim, but disabling
+	 * reclaim for kswap is a nice side-effect as kswapd causes rather
+	 * suboptimal I/O patters, too.
+	 *
+	 * This should really be done by the core VM, but until that happens
+	 * filesystems like XFS, btrfs and ext4 have to take care of this
+	 * by themselves.
+	 */
+	if (current->flags & PF_MEMALLOC)
+		goto out_fail;
 
-	if (startio) {
-		if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
-			trylock |= BMAPI_TRYLOCK;
+	/*
+	 * We need a transaction if:
+	 *  1. There are delalloc buffers on the page
+	 *  2. The page is uptodate and we have unmapped buffers
+	 *  3. The page is uptodate and we have no buffers
+	 *  4. There are unwritten buffers on the page
+	 */
+	if (!page_has_buffers(page)) {
+		unmapped = 1;
+		need_trans = 1;
+	} else {
+		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
+		if (!PageUptodate(page))
+			unmapped = 0;
+		need_trans = delalloc + unmapped + unwritten;
 	}
 
+	/*
+	 * If we need a transaction and the process flags say
+	 * we are already in a transaction, or no IO is allowed
+	 * then mark the page dirty again and leave the page
+	 * as is.
+	 */
+	if (current_test_flags(PF_FSTRANS) && need_trans)
+		goto out_fail;
+
+	/*
+	 * Delay hooking up buffer heads until we have
+	 * made our go/no-go decision.
+	 */
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, 1 << inode->i_blkbits, 0);
+
 	/* Is this page beyond the end of the file? */
 	offset = i_size_read(inode);
 	end_index = offset >> PAGE_CACHE_SHIFT;
@@ -1077,53 +1111,27 @@ xfs_page_state_convert(
 	if (page->index >= end_index) {
 		if ((page->index >= end_index + 1) ||
 		    !(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
-			if (startio)
-				unlock_page(page);
+			unlock_page(page);
 			return 0;
 		}
 	}
 
-	/*
-	 * page_dirty is initially a count of buffers on the page before
-	 * EOF and is decremented as we move each into a cleanable state.
-	 *
-	 * Derivation:
-	 *
-	 * End offset is the highest offset that this page should represent.
-	 * If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
-	 * will evaluate non-zero and be less than PAGE_CACHE_SIZE and
-	 * hence give us the correct page_dirty count. On any other page,
-	 * it will be zero and in that case we need page_dirty to be the
-	 * count of buffers on the page.
- 	 */
 	end_offset = min_t(unsigned long long,
 			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
 	len = 1 << inode->i_blkbits;
-	p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
-					PAGE_CACHE_SIZE);
-	p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
-	page_dirty = p_offset / len;
 
 	bh = head = page_buffers(page);
 	offset = page_offset(page);
 	flags = BMAPI_READ;
 	type = IO_NEW;
 
-	/* TODO: cleanup count and page_dirty */
+	all_bh = unmapped;
 
 	do {
 		if (offset >= end_offset)
 			break;
 		if (!buffer_uptodate(bh))
 			uptodate = 0;
-		if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) {
-			/*
-			 * the iomap is actually still valid, but the ioend
-			 * isn't.  shouldn't happen too often.
-			 */
-			imap_valid = 0;
-			continue;
-		}
 
 		/*
 		 * A hole may still be marked uptodate because discard_buffer
@@ -1150,7 +1158,7 @@ xfs_page_state_convert(
 		 */
 		if (buffer_unwritten(bh) || buffer_delay(bh) ||
 		    ((buffer_uptodate(bh) || PageUptodate(page)) &&
-		     !buffer_mapped(bh) && (unmapped || startio))) {
+		     !buffer_mapped(bh))) {
 			int new_ioend = 0;
 
 			/*
@@ -1164,7 +1172,11 @@ xfs_page_state_convert(
 				flags = BMAPI_WRITE | BMAPI_IGNSTATE;
 			} else if (buffer_delay(bh)) {
 				type = IO_DELAY;
-				flags = BMAPI_ALLOCATE | trylock;
+				flags = BMAPI_ALLOCATE;
+
+				if (wbc->sync_mode == WB_SYNC_NONE &&
+				    wbc->nonblocking)
+					flags |= BMAPI_TRYLOCK;
 			} else {
 				type = IO_NEW;
 				flags = BMAPI_WRITE | BMAPI_MMAP;
@@ -1196,19 +1208,11 @@ xfs_page_state_convert(
 			}
 			if (imap_valid) {
 				xfs_map_at_offset(inode, bh, &imap, offset);
-				if (startio) {
-					xfs_add_to_ioend(inode, bh, offset,
-							type, &ioend,
-							new_ioend);
-				} else {
-					set_buffer_dirty(bh);
-					unlock_buffer(bh);
-					mark_buffer_dirty(bh);
-				}
-				page_dirty--;
+				xfs_add_to_ioend(inode, bh, offset, type,
+						 &ioend, new_ioend);
 				count++;
 			}
-		} else if (buffer_uptodate(bh) && startio) {
+		} else if (buffer_uptodate(bh)) {
 			/*
 			 * we got here because the buffer is already mapped.
 			 * That means it must already have extents allocated
@@ -1241,13 +1245,11 @@ xfs_page_state_convert(
 					all_bh = 1;
 				xfs_add_to_ioend(inode, bh, offset, type,
 						&ioend, !imap_valid);
-				page_dirty--;
 				count++;
 			} else {
 				imap_valid = 0;
 			}
-		} else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
-			   (unmapped || startio)) {
+		} else if (PageUptodate(page)) {
 			imap_valid = 0;
 		}
 
@@ -1259,8 +1261,7 @@ xfs_page_state_convert(
 	if (uptodate && bh == head)
 		SetPageUptodate(page);
 
-	if (startio)
-		xfs_start_page_writeback(page, 1, count);
+	xfs_start_page_writeback(page, 1, count);
 
 	if (ioend && imap_valid) {
 		xfs_off_t		end_index;
@@ -1278,131 +1279,28 @@ xfs_page_state_convert(
 			end_index = last_index;
 
 		xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
-					wbc, startio, all_bh, end_index);
+					wbc, all_bh, end_index);
 	}
 
 	if (iohead)
 		xfs_submit_ioend(wbc, iohead);
 
-	return page_dirty;
+	return 0;
 
 error:
 	if (iohead)
 		xfs_cancel_ioend(iohead);
 
-	/*
-	 * If it's delalloc and we have nowhere to put it,
-	 * throw it away, unless the lower layers told
-	 * us to try again.
-	 */
-	if (err != -EAGAIN) {
-		if (!unmapped)
-			xfs_aops_discard_page(page);
-		ClearPageUptodate(page);
-	}
+	if (!unmapped)
+		xfs_aops_discard_page(page);
+	ClearPageUptodate(page);
+	unlock_page(page);
 	return err;
-}
-
-/*
- * writepage: Called from one of two places:
- *
- * 1. we are flushing a delalloc buffer head.
- *
- * 2. we are writing out a dirty page. Typically the page dirty
- *    state is cleared before we get here. In this case is it
- *    conceivable we have no buffer heads.
- *
- * For delalloc space on the page we need to allocate space and
- * flush it. For unmapped buffer heads on the page we should
- * allocate space if the page is uptodate. For any other dirty
- * buffer heads on the page we should flush them.
- *
- * If we detect that a transaction would be required to flush
- * the page, we have to check the process flags first, if we
- * are already in a transaction or disk I/O during allocations
- * is off, we need to fail the writepage and redirty the page.
- */
-
-STATIC int
-xfs_vm_writepage(
-	struct page		*page,
-	struct writeback_control *wbc)
-{
-	int			error;
-	int			need_trans;
-	int			delalloc, unmapped, unwritten;
-	struct inode		*inode = page->mapping->host;
-
-	trace_xfs_writepage(inode, page, 0);
-
-	/*
-	 * Refuse to write the page out if we are called from reclaim context.
-	 *
-	 * This is primarily to avoid stack overflows when called from deep
-	 * used stacks in random callers for direct reclaim, but disabling
-	 * reclaim for kswap is a nice side-effect as kswapd causes rather
-	 * suboptimal I/O patters, too.
-	 *
-	 * This should really be done by the core VM, but until that happens
-	 * filesystems like XFS, btrfs and ext4 have to take care of this
-	 * by themselves.
-	 */
-	if (current->flags & PF_MEMALLOC)
-		goto out_fail;
-
-	/*
-	 * We need a transaction if:
-	 *  1. There are delalloc buffers on the page
-	 *  2. The page is uptodate and we have unmapped buffers
-	 *  3. The page is uptodate and we have no buffers
-	 *  4. There are unwritten buffers on the page
-	 */
-
-	if (!page_has_buffers(page)) {
-		unmapped = 1;
-		need_trans = 1;
-	} else {
-		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
-		if (!PageUptodate(page))
-			unmapped = 0;
-		need_trans = delalloc + unmapped + unwritten;
-	}
-
-	/*
-	 * If we need a transaction and the process flags say
-	 * we are already in a transaction, or no IO is allowed
-	 * then mark the page dirty again and leave the page
-	 * as is.
-	 */
-	if (current_test_flags(PF_FSTRANS) && need_trans)
-		goto out_fail;
-
-	/*
-	 * Delay hooking up buffer heads until we have
-	 * made our go/no-go decision.
-	 */
-	if (!page_has_buffers(page))
-		create_empty_buffers(page, 1 << inode->i_blkbits, 0);
-
-	/*
-	 * Convert delayed allocate, unwritten or unmapped space
-	 * to real space and flush out to disk.
-	 */
-	error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
-	if (error == -EAGAIN)
-		goto out_fail;
-	if (unlikely(error < 0))
-		goto out_unlock;
-
-	return 0;
 
 out_fail:
 	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
 	return 0;
-out_unlock:
-	unlock_page(page);
-	return error;
 }
 
 STATIC int
@@ -1416,65 +1314,27 @@ xfs_vm_writepages(
 
 /*
  * Called to move a page into cleanable state - and from there
- * to be released. Possibly the page is already clean. We always
+ * to be released. The page should already be clean. We always
  * have buffer heads in this call.
  *
- * Returns 0 if the page is ok to release, 1 otherwise.
- *
- * Possible scenarios are:
- *
- * 1. We are being called to release a page which has been written
- *    to via regular I/O. buffer heads will be dirty and possibly
- *    delalloc. If no delalloc buffer heads in this case then we
- *    can just return zero.
- *
- * 2. We are called to release a page which has been written via
- *    mmap, all we need to do is ensure there is no delalloc
- *    state in the buffer heads, if not we can let the caller
- *    free them and we should come back later via writepage.
+ * Returns 1 if the page is ok to release, 0 otherwise.
  */
 STATIC int
 xfs_vm_releasepage(
 	struct page		*page,
 	gfp_t			gfp_mask)
 {
-	struct inode		*inode = page->mapping->host;
-	int			dirty, delalloc, unmapped, unwritten;
-	struct writeback_control wbc = {
-		.sync_mode = WB_SYNC_ALL,
-		.nr_to_write = 1,
-	};
-
-	trace_xfs_releasepage(inode, page, 0);
+	int			delalloc, unmapped, unwritten;
 
-	if (!page_has_buffers(page))
-		return 0;
+	trace_xfs_releasepage(page->mapping->host, page, 0);
 
 	xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
-	if (!delalloc && !unwritten)
-		goto free_buffers;
 
-	if (!(gfp_mask & __GFP_FS))
+	if (WARN_ON(delalloc))
 		return 0;
-
-	/* If we are already inside a transaction or the thread cannot
-	 * do I/O, we cannot release this page.
-	 */
-	if (current_test_flags(PF_FSTRANS))
+	if (WARN_ON(unwritten))
 		return 0;
 
-	/*
-	 * Convert delalloc space to real space, do not flush the
-	 * data out to disk, that will be done by the caller.
-	 * Never need to allocate space here - we will always
-	 * come back to writepage in that case.
-	 */
-	dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
-	if (dirty == 0 && !unwritten)
-		goto free_buffers;
-	return 0;
-
-free_buffers:
 	return try_to_free_buffers(page);
 }
 
-- 
cgit v1.2.3


From 20cb52ebd1b5ca6fa8a5d9b6b1392292f5ca8a45 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Thu, 24 Jun 2010 09:46:01 +1000
Subject: xfs: simplify xfs_vm_writepage

The writepage implementation in XFS still tries to deal with dirty but
unmapped buffers which used to caused by writes through shared mmaps.  Since
the introduction of ->page_mkwrite these can't happen anymore, so remove the
code dealing with them.

Note that the all_bh variable which causes us to start I/O on all buffers on
the pages was controlled by the count of unmapped buffers, which also
included those not actually dirty.  It's now unconditionally initialized to
0 but set to 1 for the case of small file size extensions.  It probably can
be removed entirely, but that's left for another patch.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 139 ++++++++++++++------------------------------
 1 file changed, 45 insertions(+), 94 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 7744a3b630e0..1776cdd944b5 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -85,18 +85,15 @@ void
 xfs_count_page_state(
 	struct page		*page,
 	int			*delalloc,
-	int			*unmapped,
 	int			*unwritten)
 {
 	struct buffer_head	*bh, *head;
 
-	*delalloc = *unmapped = *unwritten = 0;
+	*delalloc = *unwritten = 0;
 
 	bh = head = page_buffers(page);
 	do {
-		if (buffer_uptodate(bh) && !buffer_mapped(bh))
-			(*unmapped) = 1;
-		else if (buffer_unwritten(bh))
+		if (buffer_unwritten(bh))
 			(*unwritten) = 1;
 		else if (buffer_delay(bh))
 			(*delalloc) = 1;
@@ -607,31 +604,30 @@ xfs_map_at_offset(
 STATIC unsigned int
 xfs_probe_page(
 	struct page		*page,
-	unsigned int		pg_offset,
-	int			mapped)
+	unsigned int		pg_offset)
 {
+	struct buffer_head	*bh, *head;
 	int			ret = 0;
 
 	if (PageWriteback(page))
 		return 0;
+	if (!PageDirty(page))
+		return 0;
+	if (!page->mapping)
+		return 0;
+	if (!page_has_buffers(page))
+		return 0;
 
-	if (page->mapping && PageDirty(page)) {
-		if (page_has_buffers(page)) {
-			struct buffer_head	*bh, *head;
-
-			bh = head = page_buffers(page);
-			do {
-				if (!buffer_uptodate(bh))
-					break;
-				if (mapped != buffer_mapped(bh))
-					break;
-				ret += bh->b_size;
-				if (ret >= pg_offset)
-					break;
-			} while ((bh = bh->b_this_page) != head);
-		} else
-			ret = mapped ? 0 : PAGE_CACHE_SIZE;
-	}
+	bh = head = page_buffers(page);
+	do {
+		if (!buffer_uptodate(bh))
+			break;
+		if (!buffer_mapped(bh))
+			break;
+		ret += bh->b_size;
+		if (ret >= pg_offset)
+			break;
+	} while ((bh = bh->b_this_page) != head);
 
 	return ret;
 }
@@ -641,8 +637,7 @@ xfs_probe_cluster(
 	struct inode		*inode,
 	struct page		*startpage,
 	struct buffer_head	*bh,
-	struct buffer_head	*head,
-	int			mapped)
+	struct buffer_head	*head)
 {
 	struct pagevec		pvec;
 	pgoff_t			tindex, tlast, tloff;
@@ -651,7 +646,7 @@ xfs_probe_cluster(
 
 	/* First sum forwards in this page */
 	do {
-		if (!buffer_uptodate(bh) || (mapped != buffer_mapped(bh)))
+		if (!buffer_uptodate(bh) || !buffer_mapped(bh))
 			return total;
 		total += bh->b_size;
 	} while ((bh = bh->b_this_page) != head);
@@ -685,7 +680,7 @@ xfs_probe_cluster(
 				pg_offset = PAGE_CACHE_SIZE;
 
 			if (page->index == tindex && trylock_page(page)) {
-				pg_len = xfs_probe_page(page, pg_offset, mapped);
+				pg_len = xfs_probe_page(page, pg_offset);
 				unlock_page(page);
 			}
 
@@ -1021,18 +1016,12 @@ out_invalidate:
  * For delalloc space on the page we need to allocate space and flush it.
  * For unwritten space on the page we need to start the conversion to
  * regular allocated space.
- * For unmapped buffer heads on the page we should allocate space if the
- * page is uptodate.
  * For any other dirty buffer heads on the page we should flush them.
  *
  * If we detect that a transaction would be required to flush the page, we
  * have to check the process flags first, if we are already in a transaction
  * or disk I/O during allocations is off, we need to fail the writepage and
  * redirty the page.
- *
- * The bh->b_state's cannot know if any of the blocks or which block for that
- * matter are dirty due to mmap writes, and therefore bh uptodate is only
- * valid if the page itself isn't completely uptodate.
  */
 STATIC int
 xfs_vm_writepage(
@@ -1040,8 +1029,7 @@ xfs_vm_writepage(
 	struct writeback_control *wbc)
 {
 	struct inode		*inode = page->mapping->host;
-	int			need_trans;
-	int			delalloc, unmapped, unwritten;
+	int			delalloc, unwritten;
 	struct buffer_head	*bh, *head;
 	struct xfs_bmbt_irec	imap;
 	xfs_ioend_t		*ioend = NULL, *iohead = NULL;
@@ -1052,10 +1040,12 @@ xfs_vm_writepage(
 	ssize_t			size, len;
 	int			flags, err, imap_valid = 0, uptodate = 1;
 	int			count = 0;
-	int			all_bh;
+	int			all_bh = 0;
 
 	trace_xfs_writepage(inode, page, 0);
 
+	ASSERT(page_has_buffers(page));
+
 	/*
 	 * Refuse to write the page out if we are called from reclaim context.
 	 *
@@ -1072,29 +1062,15 @@ xfs_vm_writepage(
 		goto out_fail;
 
 	/*
-	 * We need a transaction if:
-	 *  1. There are delalloc buffers on the page
-	 *  2. The page is uptodate and we have unmapped buffers
-	 *  3. The page is uptodate and we have no buffers
-	 *  4. There are unwritten buffers on the page
-	 */
-	if (!page_has_buffers(page)) {
-		unmapped = 1;
-		need_trans = 1;
-	} else {
-		xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
-		if (!PageUptodate(page))
-			unmapped = 0;
-		need_trans = delalloc + unmapped + unwritten;
-	}
-
-	/*
-	 * If we need a transaction and the process flags say
-	 * we are already in a transaction, or no IO is allowed
-	 * then mark the page dirty again and leave the page
-	 * as is.
+	 * We need a transaction if there are delalloc or unwritten buffers
+	 * on the page.
+	 *
+	 * If we need a transaction and the process flags say we are already
+	 * in a transaction, or no IO is allowed then mark the page dirty
+	 * again and leave the page as is.
 	 */
-	if (current_test_flags(PF_FSTRANS) && need_trans)
+	xfs_count_page_state(page, &delalloc, &unwritten);
+	if ((current->flags & PF_FSTRANS) && (delalloc || unwritten))
 		goto out_fail;
 
 	/*
@@ -1117,7 +1093,8 @@ xfs_vm_writepage(
 	}
 
 	end_offset = min_t(unsigned long long,
-			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
+			(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
+			offset);
 	len = 1 << inode->i_blkbits;
 
 	bh = head = page_buffers(page);
@@ -1125,8 +1102,6 @@ xfs_vm_writepage(
 	flags = BMAPI_READ;
 	type = IO_NEW;
 
-	all_bh = unmapped;
-
 	do {
 		if (offset >= end_offset)
 			break;
@@ -1146,19 +1121,7 @@ xfs_vm_writepage(
 		if (imap_valid)
 			imap_valid = xfs_imap_valid(inode, &imap, offset);
 
-		/*
-		 * First case, map an unwritten extent and prepare for
-		 * extent state conversion transaction on completion.
-		 *
-		 * Second case, allocate space for a delalloc buffer.
-		 * We can return EAGAIN here in the release page case.
-		 *
-		 * Third case, an unmapped buffer was found, and we are
-		 * in a path where we need to write the whole page out.
-		 */
-		if (buffer_unwritten(bh) || buffer_delay(bh) ||
-		    ((buffer_uptodate(bh) || PageUptodate(page)) &&
-		     !buffer_mapped(bh))) {
+		if (buffer_unwritten(bh) || buffer_delay(bh)) {
 			int new_ioend = 0;
 
 			/*
@@ -1177,14 +1140,11 @@ xfs_vm_writepage(
 				if (wbc->sync_mode == WB_SYNC_NONE &&
 				    wbc->nonblocking)
 					flags |= BMAPI_TRYLOCK;
-			} else {
-				type = IO_NEW;
-				flags = BMAPI_WRITE | BMAPI_MMAP;
 			}
 
 			if (!imap_valid) {
 				/*
-				 * if we didn't have a valid mapping then we
+				 * If we didn't have a valid mapping then we
 				 * need to ensure that we put the new mapping
 				 * in a new ioend structure. This needs to be
 				 * done to ensure that the ioends correctly
@@ -1192,14 +1152,7 @@ xfs_vm_writepage(
 				 * for unwritten extent conversion.
 				 */
 				new_ioend = 1;
-				if (type == IO_NEW) {
-					size = xfs_probe_cluster(inode,
-							page, bh, head, 0);
-				} else {
-					size = len;
-				}
-
-				err = xfs_map_blocks(inode, offset, size,
+				err = xfs_map_blocks(inode, offset, len,
 						&imap, flags);
 				if (err)
 					goto error;
@@ -1220,8 +1173,7 @@ xfs_vm_writepage(
 			 */
 			if (!imap_valid || flags != BMAPI_READ) {
 				flags = BMAPI_READ;
-				size = xfs_probe_cluster(inode, page, bh,
-								head, 1);
+				size = xfs_probe_cluster(inode, page, bh, head);
 				err = xfs_map_blocks(inode, offset, size,
 						&imap, flags);
 				if (err)
@@ -1240,7 +1192,6 @@ xfs_vm_writepage(
 			 */
 			type = IO_NEW;
 			if (trylock_buffer(bh)) {
-				ASSERT(buffer_mapped(bh));
 				if (imap_valid)
 					all_bh = 1;
 				xfs_add_to_ioend(inode, bh, offset, type,
@@ -1250,6 +1201,7 @@ xfs_vm_writepage(
 				imap_valid = 0;
 			}
 		} else if (PageUptodate(page)) {
+			ASSERT(buffer_mapped(bh));
 			imap_valid = 0;
 		}
 
@@ -1291,8 +1243,7 @@ error:
 	if (iohead)
 		xfs_cancel_ioend(iohead);
 
-	if (!unmapped)
-		xfs_aops_discard_page(page);
+	xfs_aops_discard_page(page);
 	ClearPageUptodate(page);
 	unlock_page(page);
 	return err;
@@ -1324,11 +1275,11 @@ xfs_vm_releasepage(
 	struct page		*page,
 	gfp_t			gfp_mask)
 {
-	int			delalloc, unmapped, unwritten;
+	int			delalloc, unwritten;
 
 	trace_xfs_releasepage(page->mapping->host, page, 0);
 
-	xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
+	xfs_count_page_state(page, &delalloc, &unwritten);
 
 	if (WARN_ON(delalloc))
 		return 0;
-- 
cgit v1.2.3


From f2bde9b89b4d67c9bc3b963cb996f449ddcd27a4 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Thu, 24 Jun 2010 11:44:35 +1000
Subject: xfs: small cleanups for xfs_iomap / __xfs_get_blocks

Remove the flags argument to  __xfs_get_blocks as we can easily derive
it from the direct argument, and remove the unused BMAPI_MMAP flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 1776cdd944b5..88ce1c6efff0 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1295,9 +1295,9 @@ __xfs_get_blocks(
 	sector_t		iblock,
 	struct buffer_head	*bh_result,
 	int			create,
-	int			direct,
-	bmapi_flags_t		flags)
+	int			direct)
 {
+	int			flags = create ? BMAPI_WRITE : BMAPI_READ;
 	struct xfs_bmbt_irec	imap;
 	xfs_off_t		offset;
 	ssize_t			size;
@@ -1312,8 +1312,11 @@ __xfs_get_blocks(
 	if (!create && direct && offset >= i_size_read(inode))
 		return 0;
 
-	error = xfs_iomap(XFS_I(inode), offset, size,
-			     create ? flags : BMAPI_READ, &imap, &nimap, &new);
+	if (direct && create)
+		flags |= BMAPI_DIRECT;
+
+	error = xfs_iomap(XFS_I(inode), offset, size, flags, &imap, &nimap,
+			  &new);
 	if (error)
 		return -error;
 	if (nimap == 0)
@@ -1393,8 +1396,7 @@ xfs_get_blocks(
 	struct buffer_head	*bh_result,
 	int			create)
 {
-	return __xfs_get_blocks(inode, iblock,
-				bh_result, create, 0, BMAPI_WRITE);
+	return __xfs_get_blocks(inode, iblock, bh_result, create, 0);
 }
 
 STATIC int
@@ -1404,8 +1406,7 @@ xfs_get_blocks_direct(
 	struct buffer_head	*bh_result,
 	int			create)
 {
-	return __xfs_get_blocks(inode, iblock,
-				bh_result, create, 1, BMAPI_WRITE|BMAPI_DIRECT);
+	return __xfs_get_blocks(inode, iblock, bh_result, create, 1);
 }
 
 STATIC void
-- 
cgit v1.2.3


From cca28fb83d9e60779bb348edc33a62068e5f04a4 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Thu, 24 Jun 2010 11:57:09 +1000
Subject: xfs: split xfs_itrace_entry

Replace the xfs_itrace_entry catchall with specific trace points.  For
most simple callers we now use the simple inode class, which used to
be the iget class, but add more details tracing for namespace events,
which now includes the name of the directory entries manipulated.

Remove the xfs_inactive trace point, which is a duplicate of the clear_inode
one, and the xfs_change_file_space trace point, which is immediately
followed by the more specific alloc/free space trace points.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 88ce1c6efff0..ed9c3db376c3 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1513,7 +1513,7 @@ xfs_vm_bmap(
 	struct inode		*inode = (struct inode *)mapping->host;
 	struct xfs_inode	*ip = XFS_I(inode);
 
-	xfs_itrace_entry(XFS_I(inode));
+	trace_xfs_vm_bmap(XFS_I(inode));
 	xfs_ilock(ip, XFS_IOLOCK_SHARED);
 	xfs_flush_pages(ip, (xfs_off_t)0, -1, 0, FI_REMAPF);
 	xfs_iunlock(ip, XFS_IOLOCK_SHARED);
-- 
cgit v1.2.3


From d4f7a5cbd5449a3d2097f601f588886ea7b70dc3 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Mon, 28 Jun 2010 10:34:44 -0400
Subject: xfs: allow writeback from kswapd

We only need disable I/O from direct or memcg reclaim.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index ed9c3db376c3..44ac7a0e2926 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1049,16 +1049,15 @@ xfs_vm_writepage(
 	/*
 	 * Refuse to write the page out if we are called from reclaim context.
 	 *
-	 * This is primarily to avoid stack overflows when called from deep
-	 * used stacks in random callers for direct reclaim, but disabling
-	 * reclaim for kswap is a nice side-effect as kswapd causes rather
-	 * suboptimal I/O patters, too.
+	 * This avoids stack overflows when called from deeply used stacks in
+	 * random callers for direct reclaim or memcg reclaim.  We explicitly
+	 * allow reclaim from kswapd as the stack usage there is relatively low.
 	 *
 	 * This should really be done by the core VM, but until that happens
 	 * filesystems like XFS, btrfs and ext4 have to take care of this
 	 * by themselves.
 	 */
-	if (current->flags & PF_MEMALLOC)
+	if ((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == PF_MEMALLOC)
 		goto out_fail;
 
 	/*
-- 
cgit v1.2.3


From 78558fe8d8326b2395da33456cd9eec57ffc081a Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Mon, 28 Jun 2010 10:34:57 -0400
Subject: xfs: writepage always has buffers

These days we always have buffers thanks to ->page_mkwrite.  And we
already have an assert a few lines above tripping in case that was
not true due to a bug.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 7 -------
 1 file changed, 7 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 44ac7a0e2926..225ec0fa65b6 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1072,13 +1072,6 @@ xfs_vm_writepage(
 	if ((current->flags & PF_FSTRANS) && (delalloc || unwritten))
 		goto out_fail;
 
-	/*
-	 * Delay hooking up buffer heads until we have
-	 * made our go/no-go decision.
-	 */
-	if (!page_has_buffers(page))
-		create_empty_buffers(page, 1 << inode->i_blkbits, 0);
-
 	/* Is this page beyond the end of the file? */
 	offset = i_size_read(inode);
 	end_index = offset >> PAGE_CACHE_SHIFT;
-- 
cgit v1.2.3


From aea1b9532143218f8599ecedbbd6bfbf812385e1 Mon Sep 17 00:00:00 2001
From: Dave Chinner <dchinner@redhat.com>
Date: Tue, 20 Jul 2010 17:54:12 +1000
Subject: xfs: use GFP_NOFS for page cache allocation

Avoid a lockdep warning by preventing page cache allocation from
recursing back into the filesystem during memory reclaim.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 225ec0fa65b6..8abbf0532ea1 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1493,8 +1493,8 @@ xfs_vm_write_begin(
 	void			**fsdata)
 {
 	*pagep = NULL;
-	return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-								xfs_get_blocks);
+	return block_write_begin(file, mapping, pos, len, flags | AOP_FLAG_NOFS,
+				 pagep, fsdata, xfs_get_blocks);
 }
 
 STATIC sector_t
-- 
cgit v1.2.3


From 40e2e97316af6e62affab7a392e792494b8d9dde Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Sun, 18 Jul 2010 21:17:09 +0000
Subject: direct-io: move aio_complete into ->end_io

Filesystems with unwritten extent support must not complete an AIO request
until the transaction to convert the extent has been commited.  That means
the aio_complete calls needs to be moved into the ->end_io callback so
that the filesystem can control when to call it exactly.

This makes a bit of a mess out of dio_complete and the ->end_io callback
prototype even more complicated.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 8abbf0532ea1..95d1e2695c3a 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -1406,7 +1406,9 @@ xfs_end_io_direct(
 	struct kiocb	*iocb,
 	loff_t		offset,
 	ssize_t		size,
-	void		*private)
+	void		*private,
+	int		ret,
+	bool		is_async)
 {
 	xfs_ioend_t	*ioend = iocb->private;
 
@@ -1452,6 +1454,9 @@ xfs_end_io_direct(
 	 * against double-freeing.
 	 */
 	iocb->private = NULL;
+
+	if (is_async)
+		aio_complete(iocb, ret, 0);
 }
 
 STATIC ssize_t
-- 
cgit v1.2.3


From fb511f2150174b18b28ad54708c1adda0df39b17 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Sun, 18 Jul 2010 21:17:10 +0000
Subject: xfs: move aio completion after unwritten extent conversion

If we write into an unwritten extent using AIO we need to complete the AIO
request after the extent conversion has finished.  Without that a read could
race to see see the extent still unwritten and return zeros.   For synchronous
I/O we already take care of that by flushing the xfsconvertd workqueue (which
might be a bit of overkill).

To do that add iocb and result fields to struct xfs_ioend, so that we can
call aio_complete from xfs_end_io after the extent conversion has happened.
Note that we need a new result field as io_error is used for positive errno
values, while the AIO code can return negative error values and positive
transfer sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 95d1e2695c3a..13622d5ba068 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -265,8 +265,11 @@ xfs_end_io(
 		xfs_finish_ioend(ioend, 0);
 		/* ensure we don't spin on blocked ioends */
 		delay(1);
-	} else
+	} else {
+		if (ioend->io_iocb)
+			aio_complete(ioend->io_iocb, ioend->io_result, 0);
 		xfs_destroy_ioend(ioend);
+	}
 }
 
 /*
@@ -299,6 +302,8 @@ xfs_alloc_ioend(
 	atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);
 	ioend->io_offset = 0;
 	ioend->io_size = 0;
+	ioend->io_iocb = NULL;
+	ioend->io_result = 0;
 
 	INIT_WORK(&ioend->io_work, xfs_end_io);
 	return ioend;
@@ -1411,6 +1416,7 @@ xfs_end_io_direct(
 	bool		is_async)
 {
 	xfs_ioend_t	*ioend = iocb->private;
+	bool		complete_aio = is_async;
 
 	/*
 	 * Non-NULL private data means we need to issue a transaction to
@@ -1436,7 +1442,14 @@ xfs_end_io_direct(
 	if (ioend->io_type == IO_READ) {
 		xfs_finish_ioend(ioend, 0);
 	} else if (private && size > 0) {
-		xfs_finish_ioend(ioend, is_sync_kiocb(iocb));
+		if (is_async) {
+			ioend->io_iocb = iocb;
+			ioend->io_result = ret;
+			complete_aio = false;
+			xfs_finish_ioend(ioend, 0);
+		} else {
+			xfs_finish_ioend(ioend, 1);
+		}
 	} else {
 		/*
 		 * A direct I/O write ioend starts it's life in unwritten
@@ -1455,7 +1468,7 @@ xfs_end_io_direct(
 	 */
 	iocb->private = NULL;
 
-	if (is_async)
+	if (complete_aio)
 		aio_complete(iocb, ret, 0);
 }
 
-- 
cgit v1.2.3


From 209fb87a259ead17e966627b7f053d16a96898da Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@infradead.org>
Date: Sun, 18 Jul 2010 21:17:11 +0000
Subject: xfs simplify and speed up direct I/O completions

Our current handling of direct I/O completions is rather suboptimal,
because we defer it to a workqueue more often than needed, and we
perform a much to aggressive flush of the workqueue in case unwritten
extent conversions happen.

This patch changes the direct I/O reads to not even use a completion
handler, as we don't bother to use it at all, and to perform the unwritten
extent conversions in caller context for synchronous direct I/O.

For a small I/O size direct I/O workload on a consumer grade SSD, such as
the untar of a kernel tree inside qemu this patch gives speedups of
about 5%.  Getting us much closer to the speed of a native block device,
or a fully allocated XFS file.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
---
 fs/xfs/linux-2.6/xfs_aops.c | 158 +++++++++++++++++++++-----------------------
 1 file changed, 76 insertions(+), 82 deletions(-)

(limited to 'fs/xfs/linux-2.6/xfs_aops.c')

diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 13622d5ba068..d24e78f32f3e 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -202,23 +202,17 @@ xfs_setfilesize(
 }
 
 /*
- * Schedule IO completion handling on a xfsdatad if this was
- * the final hold on this ioend. If we are asked to wait,
- * flush the workqueue.
+ * Schedule IO completion handling on the final put of an ioend.
  */
 STATIC void
 xfs_finish_ioend(
-	xfs_ioend_t	*ioend,
-	int		wait)
+	struct xfs_ioend	*ioend)
 {
 	if (atomic_dec_and_test(&ioend->io_remaining)) {
-		struct workqueue_struct *wq;
-
-		wq = (ioend->io_type == IO_UNWRITTEN) ?
-			xfsconvertd_workqueue : xfsdatad_workqueue;
-		queue_work(wq, &ioend->io_work);
-		if (wait)
-			flush_workqueue(wq);
+		if (ioend->io_type == IO_UNWRITTEN)
+			queue_work(xfsconvertd_workqueue, &ioend->io_work);
+		else
+			queue_work(xfsdatad_workqueue, &ioend->io_work);
 	}
 }
 
@@ -262,7 +256,7 @@ xfs_end_io(
 	 */
 	if (error == EAGAIN) {
 		atomic_inc(&ioend->io_remaining);
-		xfs_finish_ioend(ioend, 0);
+		xfs_finish_ioend(ioend);
 		/* ensure we don't spin on blocked ioends */
 		delay(1);
 	} else {
@@ -272,6 +266,17 @@ xfs_end_io(
 	}
 }
 
+/*
+ * Call IO completion handling in caller context on the final put of an ioend.
+ */
+STATIC void
+xfs_finish_ioend_sync(
+	struct xfs_ioend	*ioend)
+{
+	if (atomic_dec_and_test(&ioend->io_remaining))
+		xfs_end_io(&ioend->io_work);
+}
+
 /*
  * Allocate and initialise an IO completion structure.
  * We need to track unwritten extent write completion here initially.
@@ -353,7 +358,7 @@ xfs_end_bio(
 	bio->bi_end_io = NULL;
 	bio_put(bio);
 
-	xfs_finish_ioend(ioend, 0);
+	xfs_finish_ioend(ioend);
 }
 
 STATIC void
@@ -495,7 +500,7 @@ xfs_submit_ioend(
 		}
 		if (bio)
 			xfs_submit_ioend_bio(wbc, ioend, bio);
-		xfs_finish_ioend(ioend, 0);
+		xfs_finish_ioend(ioend);
 	} while ((ioend = next) != NULL);
 }
 
@@ -1406,70 +1411,56 @@ xfs_get_blocks_direct(
 	return __xfs_get_blocks(inode, iblock, bh_result, create, 1);
 }
 
+/*
+ * Complete a direct I/O write request.
+ *
+ * If the private argument is non-NULL __xfs_get_blocks signals us that we
+ * need to issue a transaction to convert the range from unwritten to written
+ * extents.  In case this is regular synchronous I/O we just call xfs_end_io
+ * to do this and we are done.  But in case this was a successfull AIO
+ * request this handler is called from interrupt context, from which we
+ * can't start transactions.  In that case offload the I/O completion to
+ * the workqueues we also use for buffered I/O completion.
+ */
 STATIC void
-xfs_end_io_direct(
-	struct kiocb	*iocb,
-	loff_t		offset,
-	ssize_t		size,
-	void		*private,
-	int		ret,
-	bool		is_async)
+xfs_end_io_direct_write(
+	struct kiocb		*iocb,
+	loff_t			offset,
+	ssize_t			size,
+	void			*private,
+	int			ret,
+	bool			is_async)
 {
-	xfs_ioend_t	*ioend = iocb->private;
-	bool		complete_aio = is_async;
+	struct xfs_ioend	*ioend = iocb->private;
 
 	/*
-	 * Non-NULL private data means we need to issue a transaction to
-	 * convert a range from unwritten to written extents.  This needs
-	 * to happen from process context but aio+dio I/O completion
-	 * happens from irq context so we need to defer it to a workqueue.
-	 * This is not necessary for synchronous direct I/O, but we do
-	 * it anyway to keep the code uniform and simpler.
-	 *
-	 * Well, if only it were that simple. Because synchronous direct I/O
-	 * requires extent conversion to occur *before* we return to userspace,
-	 * we have to wait for extent conversion to complete. Look at the
-	 * iocb that has been passed to us to determine if this is AIO or
-	 * not. If it is synchronous, tell xfs_finish_ioend() to kick the
-	 * workqueue and wait for it to complete.
-	 *
-	 * The core direct I/O code might be changed to always call the
-	 * completion handler in the future, in which case all this can
-	 * go away.
+	 * blockdev_direct_IO can return an error even after the I/O
+	 * completion handler was called.  Thus we need to protect
+	 * against double-freeing.
 	 */
+	iocb->private = NULL;
+
 	ioend->io_offset = offset;
 	ioend->io_size = size;
-	if (ioend->io_type == IO_READ) {
-		xfs_finish_ioend(ioend, 0);
-	} else if (private && size > 0) {
-		if (is_async) {
+	if (private && size > 0)
+		ioend->io_type = IO_UNWRITTEN;
+
+	if (is_async) {
+		/*
+		 * If we are converting an unwritten extent we need to delay
+		 * the AIO completion until after the unwrittent extent
+		 * conversion has completed, otherwise do it ASAP.
+		 */
+		if (ioend->io_type == IO_UNWRITTEN) {
 			ioend->io_iocb = iocb;
 			ioend->io_result = ret;
-			complete_aio = false;
-			xfs_finish_ioend(ioend, 0);
 		} else {
-			xfs_finish_ioend(ioend, 1);
+			aio_complete(iocb, ret, 0);
 		}
+		xfs_finish_ioend(ioend);
 	} else {
-		/*
-		 * A direct I/O write ioend starts it's life in unwritten
-		 * state in case they map an unwritten extent.  This write
-		 * didn't map an unwritten extent so switch it's completion
-		 * handler.
-		 */
-		ioend->io_type = IO_NEW;
-		xfs_finish_ioend(ioend, 0);
+		xfs_finish_ioend_sync(ioend);
 	}
-
-	/*
-	 * blockdev_direct_IO can return an error even after the I/O
-	 * completion handler was called.  Thus we need to protect
-	 * against double-freeing.
-	 */
-	iocb->private = NULL;
-
-	if (complete_aio)
-		aio_complete(iocb, ret, 0);
 }
 
 STATIC ssize_t
@@ -1480,23 +1471,26 @@ xfs_vm_direct_IO(
 	loff_t			offset,
 	unsigned long		nr_segs)
 {
-	struct file	*file = iocb->ki_filp;
-	struct inode	*inode = file->f_mapping->host;
-	struct block_device *bdev;
-	ssize_t		ret;
-
-	bdev = xfs_find_bdev_for_inode(inode);
-
-	iocb->private = xfs_alloc_ioend(inode, rw == WRITE ?
-					IO_UNWRITTEN : IO_READ);
-
-	ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov,
-					    offset, nr_segs,
-					    xfs_get_blocks_direct,
-					    xfs_end_io_direct);
+	struct inode		*inode = iocb->ki_filp->f_mapping->host;
+	struct block_device	*bdev = xfs_find_bdev_for_inode(inode);
+	ssize_t			ret;
+
+	if (rw & WRITE) {
+		iocb->private = xfs_alloc_ioend(inode, IO_NEW);
+
+		ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov,
+						    offset, nr_segs,
+						    xfs_get_blocks_direct,
+						    xfs_end_io_direct_write);
+		if (ret != -EIOCBQUEUED && iocb->private)
+			xfs_destroy_ioend(iocb->private);
+	} else {
+		ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov,
+						    offset, nr_segs,
+						    xfs_get_blocks_direct,
+						    NULL);
+	}
 
-	if (unlikely(ret != -EIOCBQUEUED && iocb->private))
-		xfs_destroy_ioend(iocb->private);
 	return ret;
 }
 
-- 
cgit v1.2.3