1 files changed, 107 insertions, 247 deletions

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);
 }