]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blobdiff - fs/xfs/linux-2.6/xfs_aops.c
xfs: handle negative wbc->nr_to_write during sync writeback
[mirror_ubuntu-artful-kernel.git] / fs / xfs / linux-2.6 / xfs_aops.c
index 34640d6dbdcb8e6d5879c50a3acafed0cc819708..528be1ba1402f31238429931ac64e3822041d4f2 100644 (file)
 #include "xfs_inum.h"
 #include "xfs_sb.h"
 #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"
-#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"
@@ -92,18 +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;
@@ -212,23 +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);
        }
 }
 
@@ -272,11 +256,25 @@ 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
+       } else {
+               if (ioend->io_iocb)
+                       aio_complete(ioend->io_iocb, ioend->io_result, 0);
                xfs_destroy_ioend(ioend);
+       }
+}
+
+/*
+ * 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);
 }
 
 /*
@@ -309,6 +307,8 @@ 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;
@@ -358,7 +358,7 @@ xfs_end_bio(
        bio->bi_end_io = NULL;
        bio_put(bio);
 
-       xfs_finish_ioend(ioend, 0);
+       xfs_finish_ioend(ioend);
 }
 
 STATIC void
@@ -500,7 +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);
 }
 
@@ -614,31 +614,30 @@ 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;
 }
@@ -648,8 +647,7 @@ 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;
@@ -658,7 +656,7 @@ 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);
@@ -692,7 +690,7 @@ 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);
                        }
 
@@ -761,7 +759,6 @@ 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;
@@ -832,19 +829,14 @@ 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);
@@ -859,14 +851,12 @@ 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) {
+               if (--wbc->nr_to_write <= 0 &&
+                   wbc->sync_mode == WB_SYNC_NONE)
+                       done = 1;
        }
+       xfs_start_page_writeback(page, !page_dirty, count);
 
        return done;
  fail_unlock_page:
@@ -886,7 +876,6 @@ xfs_cluster_write(
        struct xfs_bmbt_irec    *imap,
        xfs_ioend_t             **ioendp,
        struct writeback_control *wbc,
-       int                     startio,
        int                     all_bh,
        pgoff_t                 tlast)
 {
@@ -902,7 +891,7 @@ 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;
                }
@@ -981,7 +970,7 @@ 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 */
@@ -1009,7 +998,7 @@ 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) {
@@ -1032,50 +1021,66 @@ 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.
  *
- * 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.
+ * 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 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_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                     delalloc, 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 = 0;
 
-       if (startio) {
-               if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
-                       trylock |= BMAPI_TRYLOCK;
-       }
+       trace_xfs_writepage(inode, page, 0);
+
+       ASSERT(page_has_buffers(page));
+
+       /*
+        * Refuse to write the page out if we are called from reclaim context.
+        *
+        * 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|PF_KSWAPD)) == PF_MEMALLOC)
+               goto out_fail;
+
+       /*
+        * 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.
+        */
+       xfs_count_page_state(page, &delalloc, &unwritten);
+       if ((current->flags & PF_FSTRANS) && (delalloc || unwritten))
+               goto out_fail;
 
        /* Is this page beyond the end of the file? */
        offset = i_size_read(inode);
@@ -1084,50 +1089,33 @@ 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);
+                       (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 */
-
        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.
-                        */
+
+               /*
+                * 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;
                }
@@ -1135,19 +1123,7 @@ xfs_page_state_convert(
                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) && (unmapped || startio))) {
+               if (buffer_unwritten(bh) || buffer_delay(bh)) {
                        int new_ioend = 0;
 
                        /*
@@ -1161,15 +1137,16 @@ xfs_page_state_convert(
                                flags = BMAPI_WRITE | BMAPI_IGNSTATE;
                        } else if (buffer_delay(bh)) {
                                type = IO_DELAY;
-                               flags = BMAPI_ALLOCATE | trylock;
-                       } else {
-                               type = IO_NEW;
-                               flags = BMAPI_WRITE | BMAPI_MMAP;
+                               flags = BMAPI_ALLOCATE;
+
+                               if (wbc->sync_mode == WB_SYNC_NONE &&
+                                   wbc->nonblocking)
+                                       flags |= BMAPI_TRYLOCK;
                        }
 
                        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
@@ -1177,14 +1154,7 @@ xfs_page_state_convert(
                                 * 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;
@@ -1193,19 +1163,11 @@ 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
@@ -1213,8 +1175,7 @@ xfs_page_state_convert(
                         */
                        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)
@@ -1233,18 +1194,16 @@ xfs_page_state_convert(
                         */
                        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,
                                                &ioend, !imap_valid);
-                               page_dirty--;
                                count++;
                        } else {
                                imap_valid = 0;
                        }
-               } else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
-                          (unmapped || startio)) {
+               } else if (PageUptodate(page)) {
+                       ASSERT(buffer_mapped(bh));
                        imap_valid = 0;
                }
 
@@ -1256,8 +1215,7 @@ 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;
@@ -1275,131 +1233,27 @@ 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);
-       }
+       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
@@ -1413,65 +1267,27 @@ 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,
-       };
+       int                     delalloc, unwritten;
 
-       trace_xfs_releasepage(inode, page, 0);
+       trace_xfs_releasepage(page->mapping->host, page, 0);
 
-       if (!page_has_buffers(page))
-               return 0;
-
-       xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
-       if (!delalloc && !unwritten)
-               goto free_buffers;
+       xfs_count_page_state(page, &delalloc, &unwritten);
 
-       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);
 }
 
@@ -1481,9 +1297,9 @@ __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;
@@ -1498,8 +1314,11 @@ __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)
@@ -1579,8 +1398,7 @@ 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
@@ -1590,61 +1408,59 @@ 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);
 }
 
+/*
+ * 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)
+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;
+       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) {
-               xfs_finish_ioend(ioend, is_sync_kiocb(iocb));
-       } else {
+       if (private && size > 0)
+               ioend->io_type = IO_UNWRITTEN;
+
+       if (is_async) {
                /*
-                * 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.
+                * 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.
                 */
-               ioend->io_type = IO_NEW;
-               xfs_finish_ioend(ioend, 0);
+               if (ioend->io_type == IO_UNWRITTEN) {
+                       ioend->io_iocb = iocb;
+                       ioend->io_result = ret;
+               } else {
+                       aio_complete(iocb, ret, 0);
+               }
+               xfs_finish_ioend(ioend);
+       } else {
+               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;
 }
 
 STATIC ssize_t
@@ -1655,26 +1471,45 @@ 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;
+       struct inode            *inode = iocb->ki_filp->f_mapping->host;
+       struct block_device     *bdev = xfs_find_bdev_for_inode(inode);
+       ssize_t                 ret;
 
-       bdev = xfs_find_bdev_for_inode(inode);
+       if (rw & WRITE) {
+               iocb->private = xfs_alloc_ioend(inode, IO_NEW);
 
-       iocb->private = xfs_alloc_ioend(inode, rw == WRITE ?
-                                       IO_UNWRITTEN : IO_READ);
-
-       ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov,
+               ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
                                            offset, nr_segs,
                                            xfs_get_blocks_direct,
-                                           xfs_end_io_direct);
+                                           xfs_end_io_direct_write, NULL, 0);
+               if (ret != -EIOCBQUEUED && iocb->private)
+                       xfs_destroy_ioend(iocb->private);
+       } else {
+               ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
+                                           offset, nr_segs,
+                                           xfs_get_blocks_direct,
+                                           NULL, NULL, 0);
+       }
 
-       if (unlikely(ret != -EIOCBQUEUED && iocb->private))
-               xfs_destroy_ioend(iocb->private);
        return ret;
 }
 
+STATIC void
+xfs_vm_write_failed(
+       struct address_space    *mapping,
+       loff_t                  to)
+{
+       struct inode            *inode = mapping->host;
+
+       if (to > inode->i_size) {
+               struct iattr    ia = {
+                       .ia_valid       = ATTR_SIZE | ATTR_FORCE,
+                       .ia_size        = inode->i_size,
+               };
+               xfs_setattr(XFS_I(inode), &ia, XFS_ATTR_NOLOCK);
+       }
+}
+
 STATIC int
 xfs_vm_write_begin(
        struct file             *file,
@@ -1685,9 +1520,31 @@ xfs_vm_write_begin(
        struct page             **pagep,
        void                    **fsdata)
 {
-       *pagep = NULL;
-       return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
-                                                               xfs_get_blocks);
+       int                     ret;
+
+       ret = block_write_begin(mapping, pos, len, flags | AOP_FLAG_NOFS,
+                               pagep, xfs_get_blocks);
+       if (unlikely(ret))
+               xfs_vm_write_failed(mapping, pos + len);
+       return ret;
+}
+
+STATIC int
+xfs_vm_write_end(
+       struct file             *file,
+       struct address_space    *mapping,
+       loff_t                  pos,
+       unsigned                len,
+       unsigned                copied,
+       struct page             *page,
+       void                    *fsdata)
+{
+       int                     ret;
+
+       ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
+       if (unlikely(ret < len))
+               xfs_vm_write_failed(mapping, pos + len);
+       return ret;
 }
 
 STATIC sector_t
@@ -1698,7 +1555,7 @@ 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);
@@ -1732,7 +1589,7 @@ const struct address_space_operations xfs_address_space_operations = {
        .releasepage            = xfs_vm_releasepage,
        .invalidatepage         = xfs_vm_invalidatepage,
        .write_begin            = xfs_vm_write_begin,
-       .write_end              = generic_write_end,
+       .write_end              = xfs_vm_write_end,
        .bmap                   = xfs_vm_bmap,
        .direct_IO              = xfs_vm_direct_IO,
        .migratepage            = buffer_migrate_page,