1 files changed, 113 insertions, 88 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ffc95ba48859..8dd22eade42c 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -41,6 +41,8 @@
 #include "acl.h"
 #include "ext4_extents.h"
 
+#define MPAGE_DA_EXTENT_TAIL 0x01
+
 static inline int ext4_begin_ordered_truncate(struct inode *inode,
                                               loff_t new_size)
 {
@@ -1626,11 +1628,13 @@ struct mpage_da_data {
         unsigned long first_page, next_page;    /* extent of pages */
         get_block_t *get_block;
         struct writeback_control *wbc;
+        int io_done;
+        long pages_written;
 };
 
 /*
  * mpage_da_submit_io - walks through extent of pages and try to write
- * them with __mpage_writepage()
+ * them with writepage() call back
  *
  * @mpd->inode: inode
  * @mpd->first_page: first page of the extent
@@ -1645,18 +1649,11 @@ struct mpage_da_data {
 static int mpage_da_submit_io(struct mpage_da_data *mpd)
 {
         struct address_space *mapping = mpd->inode->i_mapping;
-        struct mpage_data mpd_pp = {
-                .bio = NULL,
-                .last_block_in_bio = 0,
-                .get_block = mpd->get_block,
-                .use_writepage = 1,
-        };
         int ret = 0, err, nr_pages, i;
         unsigned long index, end;
         struct pagevec pvec;
 
         BUG_ON(mpd->next_page <= mpd->first_page);
-
         pagevec_init(&pvec, 0);
         index = mpd->first_page;
         end = mpd->next_page - 1;
@@ -1674,8 +1671,9 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
                                 break;
                         index++;
 
-                        err = __mpage_writepage(page, mpd->wbc, &mpd_pp);
-
+                        err = mapping->a_ops->writepage(page, mpd->wbc);
+                        if (!err)
+                                mpd->pages_written++;
                         /*
                          * In error case, we have to continue because
                          * remaining pages are still locked
@@ -1686,9 +1684,6 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
                 }
                 pagevec_release(&pvec);
         }
-        if (mpd_pp.bio)
-                mpage_bio_submit(WRITE, mpd_pp.bio);
-
         return ret;
 }
 
@@ -1711,7 +1706,7 @@ static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
         int blocks = exbh->b_size >> inode->i_blkbits;
         sector_t pblock = exbh->b_blocknr, cur_logical;
         struct buffer_head *head, *bh;
-        unsigned long index, end;
+        pgoff_t index, end;
         struct pagevec pvec;
         int nr_pages, i;
 
@@ -1796,13 +1791,11 @@ static inline void __unmap_underlying_blocks(struct inode *inode,
  *
  * The function skips space we know is already mapped to disk blocks.
  *
- * The function ignores errors ->get_block() returns, thus real
- * error handling is postponed to __mpage_writepage()
  */
 static void mpage_da_map_blocks(struct mpage_da_data *mpd)
 {
+        int err = 0;
         struct buffer_head *lbh = &mpd->lbh;
-        int err = 0, remain = lbh->b_size;
         sector_t next = lbh->b_blocknr;
         struct buffer_head new;
 
@@ -1812,35 +1805,32 @@ static void mpage_da_map_blocks(struct mpage_da_data *mpd)
         if (buffer_mapped(lbh) && !buffer_delay(lbh))
                 return;
 
-        while (remain) {
-                new.b_state = lbh->b_state;
-                new.b_blocknr = 0;
-                new.b_size = remain;
-                err = mpd->get_block(mpd->inode, next, &new, 1);
-                if (err) {
-                        /*
-                         * Rather than implement own error handling
-                         * here, we just leave remaining blocks
-                         * unallocated and try again with ->writepage()
-                         */
-                        break;
-                }
-                BUG_ON(new.b_size == 0);
+        new.b_state = lbh->b_state;
+        new.b_blocknr = 0;
+        new.b_size = lbh->b_size;
 
-                if (buffer_new(&new))
-                        __unmap_underlying_blocks(mpd->inode, &new);
+        /*
+         * If we didn't accumulate anything
+         * to write simply return
+         */
+        if (!new.b_size)
+                return;
+        err = mpd->get_block(mpd->inode, next, &new, 1);
+        if (err)
+                return;
+        BUG_ON(new.b_size == 0);
 
-                /*
-                 * If blocks are delayed marked, we need to
-                 * put actual blocknr and drop delayed bit
-                 */
-                if (buffer_delay(lbh) || buffer_unwritten(lbh))
-                        mpage_put_bnr_to_bhs(mpd, next, &new);
+        if (buffer_new(&new))
+                __unmap_underlying_blocks(mpd->inode, &new);
 
-                /* go for the remaining blocks */
-                next += new.b_size >> mpd->inode->i_blkbits;
-                remain -= new.b_size;
-        }
+        /*
+         * If blocks are delayed marked, we need to
+         * put actual blocknr and drop delayed bit
+         */
+        if (buffer_delay(lbh) || buffer_unwritten(lbh))
+                mpage_put_bnr_to_bhs(mpd, next, &new);
+
+        return;
 }
 
 #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
@@ -1886,13 +1876,9 @@ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
          * need to flush current  extent and start new one
          */
         mpage_da_map_blocks(mpd);
-
-        /*
-         * Now start a new extent
-         */
-        lbh->b_size = bh->b_size;
-        lbh->b_state = bh->b_state & BH_FLAGS;
-        lbh->b_blocknr = logical;
+        mpage_da_submit_io(mpd);
+        mpd->io_done = 1;
+        return;
 }
 
 /*
@@ -1912,17 +1898,35 @@ static int __mpage_da_writepage(struct page *page,
         struct buffer_head *bh, *head, fake;
         sector_t logical;
 
+        if (mpd->io_done) {
+                /*
+                 * Rest of the page in the page_vec
+                 * redirty then and skip then. We will
+                 * try to to write them again after
+                 * starting a new transaction
+                 */
+                redirty_page_for_writepage(wbc, page);
+                unlock_page(page);
+                return MPAGE_DA_EXTENT_TAIL;
+        }
         /*
          * Can we merge this page to current extent?
          */
         if (mpd->next_page != page->index) {
                 /*
                  * Nope, we can't. So, we map non-allocated blocks
-                 * and start IO on them using __mpage_writepage()
+                 * and start IO on them using writepage()
                  */
                 if (mpd->next_page != mpd->first_page) {
                         mpage_da_map_blocks(mpd);
                         mpage_da_submit_io(mpd);
+                        /*
+                         * skip rest of the page in the page_vec
+                         */
+                        mpd->io_done = 1;
+                        redirty_page_for_writepage(wbc, page);
+                        unlock_page(page);
+                        return MPAGE_DA_EXTENT_TAIL;
                 }
 
                 /*
@@ -1953,6 +1957,8 @@ static int __mpage_da_writepage(struct page *page,
                 set_buffer_dirty(bh);
                 set_buffer_uptodate(bh);
                 mpage_add_bh_to_extent(mpd, logical, bh);
+                if (mpd->io_done)
+                        return MPAGE_DA_EXTENT_TAIL;
         } else {
                 /*
                  * Page with regular buffer heads, just add all dirty ones
@@ -1961,8 +1967,12 @@ static int __mpage_da_writepage(struct page *page,
                 bh = head;
                 do {
                         BUG_ON(buffer_locked(bh));
-                        if (buffer_dirty(bh))
+                        if (buffer_dirty(bh) &&
+                                (!buffer_mapped(bh) || buffer_delay(bh))) {
                                 mpage_add_bh_to_extent(mpd, logical, bh);
+                                if (mpd->io_done)
+                                        return MPAGE_DA_EXTENT_TAIL;
+                        }
                         logical++;
                 } while ((bh = bh->b_this_page) != head);
         }
@@ -1981,22 +1991,13 @@ static int __mpage_da_writepage(struct page *page,
  *
  * This is a library function, which implements the writepages()
  * address_space_operation.
- *
- * In order to avoid duplication of logic that deals with partial pages,
- * multiple bio per page, etc, we find non-allocated blocks, allocate
- * them with minimal calls to ->get_block() and re-use __mpage_writepage()
- *
- * It's important that we call __mpage_writepage() only once for each
- * involved page, otherwise we'd have to implement more complicated logic
- * to deal with pages w/o PG_lock or w/ PG_writeback and so on.
- *
- * See comments to mpage_writepages()
  */
 static int mpage_da_writepages(struct address_space *mapping,
                                struct writeback_control *wbc,
                                get_block_t get_block)
 {
         struct mpage_da_data mpd;
+        long to_write;
         int ret;
 
         if (!get_block)
@@ -2010,17 +2011,22 @@ static int mpage_da_writepages(struct address_space *mapping,
         mpd.first_page = 0;
         mpd.next_page = 0;
         mpd.get_block = get_block;
+        mpd.io_done = 0;
+        mpd.pages_written = 0;
+
+        to_write = wbc->nr_to_write;
 
         ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);
 
         /*
          * Handle last extent of pages
          */
-        if (mpd.next_page != mpd.first_page) {
+        if (!mpd.io_done && mpd.next_page != mpd.first_page) {
                 mpage_da_map_blocks(&mpd);
                 mpage_da_submit_io(&mpd);
         }
 
+        wbc->nr_to_write = to_write - mpd.pages_written;
         return ret;
 }
 
@@ -2238,7 +2244,7 @@ static int ext4_da_writepage(struct page *page,
 #define EXT4_MAX_WRITEBACK_CREDITS    25
 
 static int ext4_da_writepages(struct address_space *mapping,
-                                struct writeback_control *wbc)
+                              struct writeback_control *wbc)
 {
         struct inode *inode = mapping->host;
         handle_t *handle = NULL;
@@ -2246,42 +2252,53 @@ static int ext4_da_writepages(struct address_space *mapping,
         int ret = 0;
         long to_write;
         loff_t range_start = 0;
+        long pages_skipped = 0;
 
         /*
          * No pages to write? This is mainly a kludge to avoid starting
          * a transaction for special inodes like journal inode on last iput()
          * because that could violate lock ordering on umount
          */
-        if (!mapping->nrpages)
+        if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
                 return 0;
 
-        /*
-         * Estimate the worse case needed credits to write out
-         * EXT4_MAX_BUF_BLOCKS pages
-         */
-        needed_blocks = EXT4_MAX_WRITEBACK_CREDITS;
-
-        to_write = wbc->nr_to_write;
-        if (!wbc->range_cyclic) {
+        if (!wbc->range_cyclic)
                 /*
                  * If range_cyclic is not set force range_cont
                  * and save the old writeback_index
                  */
                 wbc->range_cont = 1;
-                range_start =  wbc->range_start;
-        }
 
-        while (!ret && to_write) {
+        range_start =  wbc->range_start;
+        pages_skipped = wbc->pages_skipped;
+
+restart_loop:
+        to_write = wbc->nr_to_write;
+        while (!ret && to_write > 0) {
+
+                /*
+                 * we  insert one extent at a time. So we need
+                 * credit needed for single extent allocation.
+                 * journalled mode is currently not supported
+                 * by delalloc
+                 */
+                BUG_ON(ext4_should_journal_data(inode));
+                needed_blocks = EXT4_DATA_TRANS_BLOCKS(inode->i_sb);
+
                 /* start a new transaction*/
                 handle = ext4_journal_start(inode, needed_blocks);
                 if (IS_ERR(handle)) {
                         ret = PTR_ERR(handle);
+                        printk(KERN_EMERG "%s: jbd2_start: "
+                               "%ld pages, ino %lu; err %d\n", __func__,
+                                wbc->nr_to_write, inode->i_ino, ret);
+                        dump_stack();
                         goto out_writepages;
                 }
                 if (ext4_should_order_data(inode)) {
                         /*
                          * With ordered mode we need to add
-                         * the inode to the journal handle
+                         * the inode to the journal handl
                          * when we do block allocation.
                          */
                         ret = ext4_jbd2_file_inode(handle, inode);
@@ -2289,20 +2306,20 @@ static int ext4_da_writepages(struct address_space *mapping,
                                 ext4_journal_stop(handle);
                                 goto out_writepages;
                         }
-
                 }
-                /*
-                 * set the max dirty pages could be write at a time
-                 * to fit into the reserved transaction credits
-                 */
-                if (wbc->nr_to_write > EXT4_MAX_WRITEBACK_PAGES)
-                        wbc->nr_to_write = EXT4_MAX_WRITEBACK_PAGES;
 
                 to_write -= wbc->nr_to_write;
                 ret = mpage_da_writepages(mapping, wbc,
-                                                ext4_da_get_block_write);
+                                          ext4_da_get_block_write);
                 ext4_journal_stop(handle);
-                if (wbc->nr_to_write) {
+                if (ret == MPAGE_DA_EXTENT_TAIL) {
+                        /*
+                         * got one extent now try with
+                         * rest of the pages
+                         */
+                        to_write += wbc->nr_to_write;
+                        ret = 0;
+                } else if (wbc->nr_to_write) {
                         /*
                          * There is no more writeout needed
                          * or we requested for a noblocking writeout
@@ -2314,10 +2331,18 @@ static int ext4_da_writepages(struct address_space *mapping,
                 wbc->nr_to_write = to_write;
         }
 
+        if (wbc->range_cont && (pages_skipped != wbc->pages_skipped)) {
+                /* We skipped pages in this loop */
+                wbc->range_start = range_start;
+                wbc->nr_to_write = to_write +
+                                wbc->pages_skipped - pages_skipped;
+                wbc->pages_skipped = pages_skipped;
+                goto restart_loop;
+        }
+
 out_writepages:
         wbc->nr_to_write = to_write;
-        if (range_start)
-                wbc->range_start = range_start;
+        wbc->range_start = range_start;
         return ret;
 }