[XFS] Initial pass at going directly-to-bio on the buffered IO path. This
authorChristoph Hellwig <hch@sgi.com>
Wed, 11 Jan 2006 04:40:13 +0000 (15:40 +1100)
committerNathan Scott <nathans@sgi.com>
Wed, 11 Jan 2006 04:40:13 +0000 (15:40 +1100)
allows us to submit much larger I/Os instead of sending down lots of small
buffer_heads.  To do this we need to have a rather complicated I/O
submission and completion tracking infrastructure.  Part of the latter has
been merged already a long time ago for direct I/O support. Part of the
problem is that we need to track sub-pagesize regions and for that we
still need buffer_heads for the time beeing.  Long-term I hope we can move
to better data strucutures and/or maybe move this to fs/mpage.c instead of
having it in XFS.  Original patch from Nathan Scott with various updates
from David Chinner and Christoph Hellwig.

SGI-PV: 947118
SGI-Modid: xfs-linux-melb:xfs-kern:203822a

Signed-off-by: Christoph Hellwig <hch@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>
fs/xfs/linux-2.6/xfs_aops.c
fs/xfs/linux-2.6/xfs_aops.h
fs/xfs/linux-2.6/xfs_iops.h
fs/xfs/linux-2.6/xfs_linux.h

index 3f6b9e2..e99d04d 100644 (file)
@@ -43,8 +43,6 @@
 #include <linux/writeback.h>
 
 STATIC void xfs_count_page_state(struct page *, int *, int *, int *);
-STATIC void xfs_convert_page(struct inode *, struct page *, xfs_iomap_t *,
-               struct writeback_control *wbc, void *, int, int);
 
 #if defined(XFS_RW_TRACE)
 void
@@ -58,7 +56,7 @@ xfs_page_trace(
        bhv_desc_t      *bdp;
        vnode_t         *vp = LINVFS_GET_VP(inode);
        loff_t          isize = i_size_read(inode);
-       loff_t          offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
+       loff_t          offset = page_offset(page);
        int             delalloc = -1, unmapped = -1, unwritten = -1;
 
        if (page_has_buffers(page))
@@ -103,15 +101,56 @@ xfs_finish_ioend(
                queue_work(xfsdatad_workqueue, &ioend->io_work);
 }
 
+/*
+ * We're now finished for good with this ioend structure.
+ * Update the page state via the associated buffer_heads,
+ * release holds on the inode and bio, and finally free
+ * up memory.  Do not use the ioend after this.
+ */
 STATIC void
 xfs_destroy_ioend(
        xfs_ioend_t             *ioend)
 {
+       struct buffer_head      *bh, *next;
+
+       for (bh = ioend->io_buffer_head; bh; bh = next) {
+               next = bh->b_private;
+               bh->b_end_io(bh, ioend->io_uptodate);
+       }
+
        vn_iowake(ioend->io_vnode);
        mempool_free(ioend, xfs_ioend_pool);
 }
 
 /*
+ * Buffered IO write completion for delayed allocate extents.
+ * TODO: Update ondisk isize now that we know the file data
+ * has been flushed (i.e. the notorious "NULL file" problem).
+ */
+STATIC void
+xfs_end_bio_delalloc(
+       void                    *data)
+{
+       xfs_ioend_t             *ioend = data;
+
+       xfs_destroy_ioend(ioend);
+}
+
+/*
+ * Buffered IO write completion for regular, written extents.
+ */
+STATIC void
+xfs_end_bio_written(
+       void                    *data)
+{
+       xfs_ioend_t             *ioend = data;
+
+       xfs_destroy_ioend(ioend);
+}
+
+/*
+ * IO write completion for unwritten extents.
+ *
  * Issue transactions to convert a buffer range from unwritten
  * to written extents.
  */
@@ -123,21 +162,10 @@ xfs_end_bio_unwritten(
        vnode_t                 *vp = ioend->io_vnode;
        xfs_off_t               offset = ioend->io_offset;
        size_t                  size = ioend->io_size;
-       struct buffer_head      *bh, *next;
        int                     error;
 
        if (ioend->io_uptodate)
                VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
-
-       /* ioend->io_buffer_head is only non-NULL for buffered I/O */
-       for (bh = ioend->io_buffer_head; bh; bh = next) {
-               next = bh->b_private;
-
-               bh->b_end_io = NULL;
-               clear_buffer_unwritten(bh);
-               end_buffer_async_write(bh, ioend->io_uptodate);
-       }
-
        xfs_destroy_ioend(ioend);
 }
 
@@ -149,7 +177,8 @@ xfs_end_bio_unwritten(
  */
 STATIC xfs_ioend_t *
 xfs_alloc_ioend(
-       struct inode            *inode)
+       struct inode            *inode,
+       unsigned int            type)
 {
        xfs_ioend_t             *ioend;
 
@@ -162,45 +191,25 @@ xfs_alloc_ioend(
         */
        atomic_set(&ioend->io_remaining, 1);
        ioend->io_uptodate = 1; /* cleared if any I/O fails */
+       ioend->io_list = NULL;
+       ioend->io_type = type;
        ioend->io_vnode = LINVFS_GET_VP(inode);
        ioend->io_buffer_head = NULL;
+       ioend->io_buffer_tail = NULL;
        atomic_inc(&ioend->io_vnode->v_iocount);
        ioend->io_offset = 0;
        ioend->io_size = 0;
 
-       INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
+       if (type == IOMAP_UNWRITTEN)
+               INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
+       else if (type == IOMAP_DELAY)
+               INIT_WORK(&ioend->io_work, xfs_end_bio_delalloc, ioend);
+       else
+               INIT_WORK(&ioend->io_work, xfs_end_bio_written, ioend);
 
        return ioend;
 }
 
-void
-linvfs_unwritten_done(
-       struct buffer_head      *bh,
-       int                     uptodate)
-{
-       xfs_ioend_t             *ioend = bh->b_private;
-       static spinlock_t       unwritten_done_lock = SPIN_LOCK_UNLOCKED;
-       unsigned long           flags;
-
-       ASSERT(buffer_unwritten(bh));
-       bh->b_end_io = NULL;
-
-       if (!uptodate)
-               ioend->io_uptodate = 0;
-
-       /*
-        * Deep magic here.  We reuse b_private in the buffer_heads to build
-        * a chain for completing the I/O from user context after we've issued
-        * a transaction to convert the unwritten extent.
-        */
-       spin_lock_irqsave(&unwritten_done_lock, flags);
-       bh->b_private = ioend->io_buffer_head;
-       ioend->io_buffer_head = bh;
-       spin_unlock_irqrestore(&unwritten_done_lock, flags);
-
-       xfs_finish_ioend(ioend);
-}
-
 STATIC int
 xfs_map_blocks(
        struct inode            *inode,
@@ -228,7 +237,7 @@ xfs_offset_to_map(
        xfs_iomap_t             *iomapp,
        unsigned long           offset)
 {
-       loff_t                  full_offset;    /* offset from start of file */
+       xfs_off_t               full_offset;    /* offset from start of file */
 
        ASSERT(offset < PAGE_CACHE_SIZE);
 
@@ -243,16 +252,223 @@ xfs_offset_to_map(
        return NULL;
 }
 
+/*
+ * BIO completion handler for buffered IO.
+ */
+STATIC int
+xfs_end_bio(
+       struct bio              *bio,
+       unsigned int            bytes_done,
+       int                     error)
+{
+       xfs_ioend_t             *ioend = bio->bi_private;
+
+       if (bio->bi_size)
+               return 1;
+
+       ASSERT(ioend);
+       ASSERT(atomic_read(&bio->bi_cnt) >= 1);
+
+       /* Toss bio and pass work off to an xfsdatad thread */
+       if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+               ioend->io_uptodate = 0;
+       bio->bi_private = NULL;
+       bio->bi_end_io = NULL;
+
+       bio_put(bio);
+       xfs_finish_ioend(ioend);
+       return 0;
+}
+
+STATIC void
+xfs_submit_ioend_bio(
+       xfs_ioend_t     *ioend,
+       struct bio      *bio)
+{
+       atomic_inc(&ioend->io_remaining);
+
+       bio->bi_private = ioend;
+       bio->bi_end_io = xfs_end_bio;
+
+       submit_bio(WRITE, bio);
+       ASSERT(!bio_flagged(bio, BIO_EOPNOTSUPP));
+       bio_put(bio);
+}
+
+STATIC struct bio *
+xfs_alloc_ioend_bio(
+       struct buffer_head      *bh)
+{
+       struct bio              *bio;
+       int                     nvecs = bio_get_nr_vecs(bh->b_bdev);
+
+       do {
+               bio = bio_alloc(GFP_NOIO, nvecs);
+               nvecs >>= 1;
+       } while (!bio);
+
+       ASSERT(bio->bi_private == NULL);
+       bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
+       bio->bi_bdev = bh->b_bdev;
+       bio_get(bio);
+       return bio;
+}
+
+STATIC void
+xfs_start_buffer_writeback(
+       struct buffer_head      *bh)
+{
+       ASSERT(buffer_mapped(bh));
+       ASSERT(buffer_locked(bh));
+       ASSERT(!buffer_delay(bh));
+       ASSERT(!buffer_unwritten(bh));
+
+       mark_buffer_async_write(bh);
+       set_buffer_uptodate(bh);
+       clear_buffer_dirty(bh);
+}
+
+STATIC void
+xfs_start_page_writeback(
+       struct page             *page,
+       struct writeback_control *wbc,
+       int                     clear_dirty,
+       int                     buffers)
+{
+       ASSERT(PageLocked(page));
+       ASSERT(!PageWriteback(page));
+       set_page_writeback(page);
+       if (clear_dirty)
+               clear_page_dirty(page);
+       unlock_page(page);
+       if (!buffers) {
+               end_page_writeback(page);
+               wbc->pages_skipped++;   /* We didn't write this page */
+       }
+}
+
+static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
+{
+       return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
+}
+
+/*
+ * Submit all of the bios for all of the ioends we have saved up,
+ * covering the initial writepage page and also any probed pages.
+ */
+STATIC void
+xfs_submit_ioend(
+       xfs_ioend_t             *ioend)
+{
+       xfs_ioend_t             *next;
+       struct buffer_head      *bh;
+       struct bio              *bio;
+       sector_t                lastblock = 0;
+
+       do {
+               next = ioend->io_list;
+               bio = NULL;
+
+               for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
+                       xfs_start_buffer_writeback(bh);
+
+                       if (!bio) {
+ retry:
+                               bio = xfs_alloc_ioend_bio(bh);
+                       } else if (bh->b_blocknr != lastblock + 1) {
+                               xfs_submit_ioend_bio(ioend, bio);
+                               goto retry;
+                       }
+
+                       if (bio_add_buffer(bio, bh) != bh->b_size) {
+                               xfs_submit_ioend_bio(ioend, bio);
+                               goto retry;
+                       }
+
+                       lastblock = bh->b_blocknr;
+               }
+               if (bio)
+                       xfs_submit_ioend_bio(ioend, bio);
+               xfs_finish_ioend(ioend);
+       } while ((ioend = next) != NULL);
+}
+
+/*
+ * Cancel submission of all buffer_heads so far in this endio.
+ * Toss the endio too.  Only ever called for the initial page
+ * in a writepage request, so only ever one page.
+ */
+STATIC void
+xfs_cancel_ioend(
+       xfs_ioend_t             *ioend)
+{
+       xfs_ioend_t             *next;
+       struct buffer_head      *bh, *next_bh;
+
+       do {
+               next = ioend->io_list;
+               bh = ioend->io_buffer_head;
+               do {
+                       next_bh = bh->b_private;
+                       clear_buffer_async_write(bh);
+                       unlock_buffer(bh);
+               } while ((bh = next_bh) != NULL);
+
+               vn_iowake(ioend->io_vnode);
+               mempool_free(ioend, xfs_ioend_pool);
+       } while ((ioend = next) != NULL);
+}
+
+/*
+ * Test to see if we've been building up a completion structure for
+ * earlier buffers -- if so, we try to append to this ioend if we
+ * can, otherwise we finish off any current ioend and start another.
+ * Return true if we've finished the given ioend.
+ */
+STATIC void
+xfs_add_to_ioend(
+       struct inode            *inode,
+       struct buffer_head      *bh,
+       unsigned int            p_offset,
+       unsigned int            type,
+       xfs_ioend_t             **result,
+       int                     need_ioend)
+{
+       xfs_ioend_t             *ioend = *result;
+
+       if (!ioend || need_ioend || type != ioend->io_type) {
+               xfs_ioend_t     *previous = *result;
+               xfs_off_t       offset;
+
+               offset = (xfs_off_t)bh->b_page->index << PAGE_CACHE_SHIFT;
+               offset += p_offset;
+               ioend = xfs_alloc_ioend(inode, type);
+               ioend->io_offset = offset;
+               ioend->io_buffer_head = bh;
+               ioend->io_buffer_tail = bh;
+               if (previous)
+                       previous->io_list = ioend;
+               *result = ioend;
+       } else {
+               ioend->io_buffer_tail->b_private = bh;
+               ioend->io_buffer_tail = bh;
+       }
+
+       bh->b_private = NULL;
+       ioend->io_size += bh->b_size;
+}
+
 STATIC void
 xfs_map_at_offset(
        struct page             *page,
        struct buffer_head      *bh,
        unsigned long           offset,
        int                     block_bits,
-       xfs_iomap_t             *iomapp)
+       xfs_iomap_t             *iomapp,
+       xfs_ioend_t             *ioend)
 {
        xfs_daddr_t             bn;
-       loff_t                  delta;
+       xfs_off_t               delta;
        int                     sector_shift;
 
        ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
@@ -276,60 +492,7 @@ xfs_map_at_offset(
        bh->b_bdev = iomapp->iomap_target->bt_bdev;
        set_buffer_mapped(bh);
        clear_buffer_delay(bh);
-}
-
-/*
- * Look for a page at index which is unlocked and contains our
- * unwritten extent flagged buffers at its head.  Returns page
- * locked and with an extra reference count, and length of the
- * unwritten extent component on this page that we can write,
- * in units of filesystem blocks.
- */
-STATIC struct page *
-xfs_probe_unwritten_page(
-       struct address_space    *mapping,
-       pgoff_t                 index,
-       xfs_iomap_t             *iomapp,
-       xfs_ioend_t             *ioend,
-       unsigned long           max_offset,
-       unsigned long           *fsbs,
-       unsigned int            bbits)
-{
-       struct page             *page;
-
-       page = find_trylock_page(mapping, index);
-       if (!page)
-               return NULL;
-       if (PageWriteback(page))
-               goto out;
-
-       if (page->mapping && page_has_buffers(page)) {
-               struct buffer_head      *bh, *head;
-               unsigned long           p_offset = 0;
-
-               *fsbs = 0;
-               bh = head = page_buffers(page);
-               do {
-                       if (!buffer_unwritten(bh) || !buffer_uptodate(bh))
-                               break;
-                       if (!xfs_offset_to_map(page, iomapp, p_offset))
-                               break;
-                       if (p_offset >= max_offset)
-                               break;
-                       xfs_map_at_offset(page, bh, p_offset, bbits, iomapp);
-                       set_buffer_unwritten_io(bh);
-                       bh->b_private = ioend;
-                       p_offset += bh->b_size;
-                       (*fsbs)++;
-               } while ((bh = bh->b_this_page) != head);
-
-               if (p_offset)
-                       return page;
-       }
-
-out:
-       unlock_page(page);
-       return NULL;
+       clear_buffer_unwritten(bh);
 }
 
 /*
@@ -372,15 +535,16 @@ out:
        return ret;
 }
 
-STATIC unsigned int
+STATIC size_t
 xfs_probe_unmapped_cluster(
        struct inode            *inode,
        struct page             *startpage,
        struct buffer_head      *bh,
        struct buffer_head      *head)
 {
+       size_t                  len, total = 0;
        pgoff_t                 tindex, tlast, tloff;
-       unsigned int            pg_offset, len, total = 0;
+       unsigned int            pg_offset;
        struct address_space    *mapping = inode->i_mapping;
 
        /* First sum forwards in this page */
@@ -414,14 +578,15 @@ xfs_probe_unmapped_cluster(
 }
 
 /*
- * Probe for a given page (index) in the inode and test if it is delayed
- * and without unwritten buffers.  Returns page locked and with an extra
- * reference count.
+ * Probe for a given page (index) in the inode and test if it is suitable
+ * for writing as part of an unwritten or delayed allocate extent.
+ * Returns page locked and with an extra reference count if so, else NULL.
  */
 STATIC struct page *
-xfs_probe_delalloc_page(
+xfs_probe_delayed_page(
        struct inode            *inode,
-       pgoff_t                 index)
+       pgoff_t                 index,
+       unsigned int            type)
 {
        struct page             *page;
 
@@ -437,12 +602,12 @@ xfs_probe_delalloc_page(
 
                bh = head = page_buffers(page);
                do {
-                       if (buffer_unwritten(bh)) {
-                               acceptable = 0;
+                       if (buffer_unwritten(bh))
+                               acceptable = (type == IOMAP_UNWRITTEN);
+                       else if (buffer_delay(bh))
+                               acceptable = (type == IOMAP_DELAY);
+                       else
                                break;
-                       } else if (buffer_delay(bh)) {
-                               acceptable = 1;
-                       }
                } while ((bh = bh->b_this_page) != head);
 
                if (acceptable)
@@ -454,161 +619,30 @@ out:
        return NULL;
 }
 
-STATIC int
-xfs_map_unwritten(
-       struct inode            *inode,
-       struct page             *start_page,
-       struct buffer_head      *head,
-       struct buffer_head      *curr,
-       unsigned long           p_offset,
-       int                     block_bits,
-       xfs_iomap_t             *iomapp,
-       struct writeback_control *wbc,
-       int                     startio,
-       int                     all_bh)
-{
-       struct buffer_head      *bh = curr;
-       xfs_iomap_t             *tmp;
-       xfs_ioend_t             *ioend;
-       loff_t                  offset;
-       unsigned long           nblocks = 0;
-
-       offset = start_page->index;
-       offset <<= PAGE_CACHE_SHIFT;
-       offset += p_offset;
-
-       ioend = xfs_alloc_ioend(inode);
-
-       /* First map forwards in the page consecutive buffers
-        * covering this unwritten extent
-        */
-       do {
-               if (!buffer_unwritten(bh))
-                       break;
-               tmp = xfs_offset_to_map(start_page, iomapp, p_offset);
-               if (!tmp)
-                       break;
-               xfs_map_at_offset(start_page, bh, p_offset, block_bits, iomapp);
-               set_buffer_unwritten_io(bh);
-               bh->b_private = ioend;
-               p_offset += bh->b_size;
-               nblocks++;
-       } while ((bh = bh->b_this_page) != head);
-
-       atomic_add(nblocks, &ioend->io_remaining);
-
-       /* If we reached the end of the page, map forwards in any
-        * following pages which are also covered by this extent.
-        */
-       if (bh == head) {
-               struct address_space    *mapping = inode->i_mapping;
-               pgoff_t                 tindex, tloff, tlast;
-               unsigned long           bs;
-               unsigned int            pg_offset, bbits = inode->i_blkbits;
-               struct page             *page;
-
-               tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
-               tloff = (iomapp->iomap_offset + iomapp->iomap_bsize) >> PAGE_CACHE_SHIFT;
-               tloff = min(tlast, tloff);
-               for (tindex = start_page->index + 1; tindex < tloff; tindex++) {
-                       page = xfs_probe_unwritten_page(mapping,
-                                               tindex, iomapp, ioend,
-                                               PAGE_CACHE_SIZE, &bs, bbits);
-                       if (!page)
-                               break;
-                       nblocks += bs;
-                       atomic_add(bs, &ioend->io_remaining);
-                       xfs_convert_page(inode, page, iomapp, wbc, ioend,
-                                                       startio, all_bh);
-                       /* stop if converting the next page might add
-                        * enough blocks that the corresponding byte
-                        * count won't fit in our ulong page buf length */
-                       if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
-                               goto enough;
-               }
-
-               if (tindex == tlast &&
-                   (pg_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1)))) {
-                       page = xfs_probe_unwritten_page(mapping,
-                                                       tindex, iomapp, ioend,
-                                                       pg_offset, &bs, bbits);
-                       if (page) {
-                               nblocks += bs;
-                               atomic_add(bs, &ioend->io_remaining);
-                               xfs_convert_page(inode, page, iomapp, wbc, ioend,
-                                                       startio, all_bh);
-                               if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
-                                       goto enough;
-                       }
-               }
-       }
-
-enough:
-       ioend->io_size = (xfs_off_t)nblocks << block_bits;
-       ioend->io_offset = offset;
-       xfs_finish_ioend(ioend);
-       return 0;
-}
-
-STATIC void
-xfs_submit_page(
-       struct page             *page,
-       struct writeback_control *wbc,
-       struct buffer_head      *bh_arr[],
-       int                     bh_count,
-       int                     probed_page,
-       int                     clear_dirty)
-{
-       struct buffer_head      *bh;
-       int                     i;
-
-       BUG_ON(PageWriteback(page));
-       if (bh_count)
-               set_page_writeback(page);
-       if (clear_dirty)
-               clear_page_dirty(page);
-       unlock_page(page);
-
-       if (bh_count) {
-               for (i = 0; i < bh_count; i++) {
-                       bh = bh_arr[i];
-                       mark_buffer_async_write(bh);
-                       if (buffer_unwritten(bh))
-                               set_buffer_unwritten_io(bh);
-                       set_buffer_uptodate(bh);
-                       clear_buffer_dirty(bh);
-               }
-
-               for (i = 0; i < bh_count; i++)
-                       submit_bh(WRITE, bh_arr[i]);
-
-               if (probed_page && clear_dirty)
-                       wbc->nr_to_write--;     /* Wrote an "extra" page */
-       }
-}
-
 /*
  * Allocate & map buffers for page given the extent map. Write it out.
  * except for the original page of a writepage, this is called on
  * delalloc/unwritten pages only, for the original page it is possible
  * that the page has no mapping at all.
  */
-STATIC void
+STATIC int
 xfs_convert_page(
        struct inode            *inode,
        struct page             *page,
        xfs_iomap_t             *iomapp,
+       xfs_ioend_t             **ioendp,
        struct writeback_control *wbc,
        void                    *private,
        int                     startio,
        int                     all_bh)
 {
-       struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
+       struct buffer_head      *bh, *head;
        xfs_iomap_t             *mp = iomapp, *tmp;
-       unsigned long           offset, end_offset;
-       int                     index = 0;
+       unsigned long           p_offset, end_offset;
+       unsigned int            type;
        int                     bbits = inode->i_blkbits;
        int                     len, page_dirty;
+       int                     count = 0, done = 0, uptodate = 1;
 
        end_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1));
 
@@ -621,59 +655,66 @@ xfs_convert_page(
        end_offset = roundup(end_offset, len);
        page_dirty = end_offset / len;
 
-       offset = 0;
+       p_offset = 0;
        bh = head = page_buffers(page);
        do {
-               if (offset >= end_offset)
+               if (p_offset >= end_offset)
                        break;
-               if (!(PageUptodate(page) || buffer_uptodate(bh)))
+               if (!buffer_uptodate(bh))
+                       uptodate = 0;
+               if (!(PageUptodate(page) || buffer_uptodate(bh))) {
+                       done = 1;
                        continue;
-               if (buffer_mapped(bh) && all_bh &&
-                   !(buffer_unwritten(bh) || buffer_delay(bh))) {
-                       if (startio) {
+               }
+
+               if (buffer_unwritten(bh))
+                       type = IOMAP_UNWRITTEN;
+               else if (buffer_delay(bh))
+                       type = IOMAP_DELAY;
+               else {
+                       type = 0;
+                       if (!(buffer_mapped(bh) && all_bh && startio)) {
+                               done = 1;
+                       } else if (startio) {
                                lock_buffer(bh);
-                               bh_arr[index++] = bh;
+                               xfs_add_to_ioend(inode, bh, p_offset,
+                                               type, ioendp, done);
+                               count++;
                                page_dirty--;
                        }
                        continue;
                }
-               tmp = xfs_offset_to_map(page, mp, offset);
-               if (!tmp)
+               tmp = xfs_offset_to_map(page, mp, p_offset);
+               if (!tmp) {
+                       done = 1;
                        continue;
+               }
                ASSERT(!(tmp->iomap_flags & IOMAP_HOLE));
                ASSERT(!(tmp->iomap_flags & IOMAP_DELAY));
 
-               /* If this is a new unwritten extent buffer (i.e. one
-                * that we haven't passed in private data for, we must
-                * now map this buffer too.
-                */
-               if (buffer_unwritten(bh) && !bh->b_end_io) {
-                       ASSERT(tmp->iomap_flags & IOMAP_UNWRITTEN);
-                       xfs_map_unwritten(inode, page, head, bh, offset,
-                                       bbits, tmp, wbc, startio, all_bh);
-               } else if (! (buffer_unwritten(bh) && buffer_locked(bh))) {
-                       xfs_map_at_offset(page, bh, offset, bbits, tmp);
-                       if (buffer_unwritten(bh)) {
-                               set_buffer_unwritten_io(bh);
-                               bh->b_private = private;
-                               ASSERT(private);
-                       }
-               }
+               xfs_map_at_offset(page, bh, p_offset, bbits, tmp, *ioendp);
                if (startio) {
-                       bh_arr[index++] = bh;
+                       xfs_add_to_ioend(inode, bh, p_offset,
+                                       type, ioendp, done);
+                       count++;
                } else {
                        set_buffer_dirty(bh);
                        unlock_buffer(bh);
                        mark_buffer_dirty(bh);
                }
                page_dirty--;
-       } while (offset += len, (bh = bh->b_this_page) != head);
+       } while (p_offset += len, (bh = bh->b_this_page) != head);
 
-       if (startio && index) {
-               xfs_submit_page(page, wbc, bh_arr, index, 1, !page_dirty);
-       } else {
-               unlock_page(page);
+       if (uptodate && bh == head)
+               SetPageUptodate(page);
+
+       if (startio) {
+               if (count)
+                       wbc->nr_to_write--;
+               xfs_start_page_writeback(page, wbc, !page_dirty, count);
        }
+
+       return done;
 }
 
 /*
@@ -685,19 +726,22 @@ xfs_cluster_write(
        struct inode            *inode,
        pgoff_t                 tindex,
        xfs_iomap_t             *iomapp,
+       xfs_ioend_t             **ioendp,
        struct writeback_control *wbc,
        int                     startio,
        int                     all_bh,
        pgoff_t                 tlast)
 {
        struct page             *page;
+       unsigned int            type = (*ioendp)->io_type;
+       int                     done;
 
-       for (; tindex <= tlast; tindex++) {
-               page = xfs_probe_delalloc_page(inode, tindex);
+       for (done = 0; tindex <= tlast && !done; tindex++) {
+               page = xfs_probe_delayed_page(inode, tindex, type);
                if (!page)
                        break;
-               xfs_convert_page(inode, page, iomapp, wbc, NULL,
-                               startio, all_bh);
+               done = xfs_convert_page(inode, page, iomapp, ioendp,
+                                               wbc, NULL, startio, all_bh);
        }
 }
 
@@ -728,18 +772,21 @@ xfs_page_state_convert(
        int             startio,
        int             unmapped) /* also implies page uptodate */
 {
-       struct buffer_head      *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
+       struct buffer_head      *bh, *head;
        xfs_iomap_t             *iomp, iomap;
+       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, tlast;
-       int                     len, err, i, cnt = 0, uptodate = 1;
-       int                     flags;
-       int                     page_dirty;
+       int                     flags, len, err, done = 1;
+       int                     uptodate = 1;
+       int                     page_dirty, count = 0, trylock_flag = 0;
 
        /* wait for other IO threads? */
-       flags = (startio && wbc->sync_mode != WB_SYNC_NONE) ? 0 : BMAPI_TRYLOCK;
+       if (startio && wbc->sync_mode != WB_SYNC_NONE)
+               trylock_flag |= BMAPI_TRYLOCK;
 
        /* Is this page beyond the end of the file? */
        offset = i_size_read(inode);
@@ -754,98 +801,98 @@ xfs_page_state_convert(
                }
        }
 
-       end_offset = min_t(unsigned long long,
-                       (loff_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
-       offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
-
        /*
         * page_dirty is initially a count of buffers on the page before
         * EOF and is decrememted 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 = max(p_offset, PAGE_CACHE_SIZE);
-       p_offset = roundup(p_offset, len);
+       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;
 
        iomp = NULL;
-       p_offset = 0;
        bh = head = page_buffers(page);
+       offset = page_offset(page);
+
+       /* TODO: fix up "done" variable and iomap pointer (boolean) */
+       /* 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)
+               if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) {
+                       done = 1;
                        continue;
+               }
 
                if (iomp) {
                        iomp = xfs_offset_to_map(page, &iomap, p_offset);
+                       done = (iomp == NULL);
                }
 
                /*
                 * First case, map an unwritten extent and prepare for
                 * extent state conversion transaction on completion.
-                */
-               if (buffer_unwritten(bh)) {
-                       if (!startio)
-                               continue;
-                       if (!iomp) {
-                               err = xfs_map_blocks(inode, offset, len, &iomap,
-                                               BMAPI_WRITE|BMAPI_IGNSTATE);
-                               if (err) {
-                                       goto error;
-                               }
-                               iomp = xfs_offset_to_map(page, &iomap,
-                                                               p_offset);
-                       }
-                       if (iomp) {
-                               if (!bh->b_end_io) {
-                                       err = xfs_map_unwritten(inode, page,
-                                                       head, bh, p_offset,
-                                                       inode->i_blkbits, iomp,
-                                                       wbc, startio, unmapped);
-                                       if (err) {
-                                               goto error;
-                                       }
-                               } else {
-                                       set_bit(BH_Lock, &bh->b_state);
-                               }
-                               BUG_ON(!buffer_locked(bh));
-                               bh_arr[cnt++] = bh;
-                               page_dirty--;
-                       }
-               /*
+                *
                 * Second case, allocate space for a delalloc buffer.
                 * We can return EAGAIN here in the release page case.
                 */
-               } else if (buffer_delay(bh)) {
+               if (buffer_unwritten(bh) || buffer_delay(bh)) {
+                       if (buffer_unwritten(bh)) {
+                               type = IOMAP_UNWRITTEN;
+                               flags = BMAPI_WRITE|BMAPI_IGNSTATE;
+                       } else {
+                               type = IOMAP_DELAY;
+                               flags = BMAPI_ALLOCATE;
+                               if (!startio)
+                                       flags |= trylock_flag;
+                       }
+
                        if (!iomp) {
+                               done = 1;
                                err = xfs_map_blocks(inode, offset, len, &iomap,
-                                               BMAPI_ALLOCATE | flags);
-                               if (err) {
+                                               flags);
+                               if (err)
                                        goto error;
-                               }
                                iomp = xfs_offset_to_map(page, &iomap,
                                                                p_offset);
+                               done = (iomp == NULL);
                        }
                        if (iomp) {
                                xfs_map_at_offset(page, bh, p_offset,
-                                               inode->i_blkbits, iomp);
+                                               inode->i_blkbits, iomp, ioend);
                                if (startio) {
-                                       bh_arr[cnt++] = bh;
+                                       xfs_add_to_ioend(inode, bh, p_offset,
+                                               type, &ioend, done);
                                } else {
                                        set_buffer_dirty(bh);
                                        unlock_buffer(bh);
                                        mark_buffer_dirty(bh);
                                }
                                page_dirty--;
+                               count++;
+                       } else {
+                               done = 1;
                        }
                } else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
                           (unmapped || startio)) {
 
+                       type = 0;
                        if (!buffer_mapped(bh)) {
-                               int     size;
 
                                /*
                                 * Getting here implies an unmapped buffer
@@ -853,6 +900,8 @@ xfs_page_state_convert(
                                 * need to write the whole page out.
                                 */
                                if (!iomp) {
+                                       int     size;
+
                                        size = xfs_probe_unmapped_cluster(
                                                        inode, page, bh, head);
                                        err = xfs_map_blocks(inode, offset,
@@ -863,52 +912,70 @@ xfs_page_state_convert(
                                        }
                                        iomp = xfs_offset_to_map(page, &iomap,
                                                                     p_offset);
+                                       done = (iomp == NULL);
                                }
                                if (iomp) {
-                                       xfs_map_at_offset(page,
-                                                       bh, p_offset,
-                                                       inode->i_blkbits, iomp);
+                                       xfs_map_at_offset(page, bh, p_offset,
+                                                       inode->i_blkbits, iomp,
+                                                       ioend);
                                        if (startio) {
-                                               bh_arr[cnt++] = bh;
+                                               xfs_add_to_ioend(inode,
+                                                       bh, p_offset, type,
+                                                       &ioend, done);
                                        } else {
                                                set_buffer_dirty(bh);
                                                unlock_buffer(bh);
                                                mark_buffer_dirty(bh);
                                        }
                                        page_dirty--;
+                                       count++;
+                               } else {
+                                       done = 1;
                                }
                        } else if (startio) {
                                if (buffer_uptodate(bh) &&
                                    !test_and_set_bit(BH_Lock, &bh->b_state)) {
-                                       bh_arr[cnt++] = bh;
+                                       ASSERT(buffer_mapped(bh));
+                                       xfs_add_to_ioend(inode,
+                                                       bh, p_offset, type,
+                                                       &ioend, done);
                                        page_dirty--;
+                                       count++;
+                               } else {
+                                       done = 1;
                                }
+                       } else {
+                               done = 1;
                        }
                }
-       } while (offset += len, p_offset += len,
-               ((bh = bh->b_this_page) != head));
+
+               if (!iohead)
+                       iohead = ioend;
+
+       } while (offset += len, ((bh = bh->b_this_page) != head));
 
        if (uptodate && bh == head)
                SetPageUptodate(page);
 
-       if (startio) {
-               xfs_submit_page(page, wbc, bh_arr, cnt, 0, !page_dirty);
-       }
+       if (startio)
+               xfs_start_page_writeback(page, wbc, 1, count);
 
-       if (iomp) {
+       if (ioend && iomp && !done) {
                offset = (iomp->iomap_offset + iomp->iomap_bsize - 1) >>
                                        PAGE_CACHE_SHIFT;
                tlast = min_t(pgoff_t, offset, last_index);
-               xfs_cluster_write(inode, page->index + 1, iomp, wbc,
-                                       startio, unmapped, tlast);
+               xfs_cluster_write(inode, page->index + 1, iomp, &ioend,
+                                       wbc, startio, unmapped, tlast);
        }
 
+       if (iohead)
+               xfs_submit_ioend(iohead);
+
        return page_dirty;
 
 error:
-       for (i = 0; i < cnt; i++) {
-               unlock_buffer(bh_arr[i]);
-       }
+       if (iohead)
+               xfs_cancel_ioend(iohead);
 
        /*
         * If it's delalloc and we have nowhere to put it,
@@ -916,9 +983,8 @@ error:
         * us to try again.
         */
        if (err != -EAGAIN) {
-               if (!unmapped) {
+               if (!unmapped)
                        block_invalidatepage(page, 0);
-               }
                ClearPageUptodate(page);
        }
        return err;
@@ -1094,7 +1160,7 @@ linvfs_direct_IO(
        if (error)
                return -error;
 
-       iocb->private = xfs_alloc_ioend(inode);
+       iocb->private = xfs_alloc_ioend(inode, IOMAP_UNWRITTEN);
 
        ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
                iomap.iomap_target->bt_bdev,
index 4720758..55339dd 100644 (file)
@@ -23,14 +23,24 @@ extern mempool_t *xfs_ioend_pool;
 
 typedef void (*xfs_ioend_func_t)(void *);
 
+/*
+ * xfs_ioend struct manages large extent writes for XFS.
+ * It can manage several multi-page bio's at once.
+ */
 typedef struct xfs_ioend {
+       struct xfs_ioend        *io_list;       /* next ioend in chain */
+       unsigned int            io_type;        /* delalloc / unwritten */
        unsigned int            io_uptodate;    /* I/O status register */
        atomic_t                io_remaining;   /* hold count */
        struct vnode            *io_vnode;      /* file being written to */
        struct buffer_head      *io_buffer_head;/* buffer linked list head */
+       struct buffer_head      *io_buffer_tail;/* buffer linked list tail */
        size_t                  io_size;        /* size of the extent */
        xfs_off_t               io_offset;      /* offset in the file */
        struct work_struct      io_work;        /* xfsdatad work queue */
 } xfs_ioend_t;
 
+extern struct address_space_operations linvfs_aops;
+extern int linvfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
+
 #endif /* __XFS_IOPS_H__ */
index ee784b6..6899a6b 100644 (file)
@@ -26,11 +26,6 @@ extern struct file_operations linvfs_file_operations;
 extern struct file_operations linvfs_invis_file_operations;
 extern struct file_operations linvfs_dir_operations;
 
-extern struct address_space_operations linvfs_aops;
-
-extern int linvfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
-extern void linvfs_unwritten_done(struct buffer_head *, int);
-
 extern int xfs_ioctl(struct bhv_desc *, struct inode *, struct file *,
                         int, unsigned int, void __user *);
 
index 95efe94..67389b7 100644 (file)
  * delalloc and these ondisk-uninitialised buffers.
  */
 BUFFER_FNS(PrivateStart, unwritten);
-static inline void set_buffer_unwritten_io(struct buffer_head *bh)
-{
-       bh->b_end_io = linvfs_unwritten_done;
-}
 
 #define restricted_chown       xfs_params.restrict_chown.val
 #define irix_sgid_inherit      xfs_params.sgid_inherit.val