jfs: Fix error handling in metapage_writepage()

Improved error handling so that last_write_complete(), and thus
end_page_writeback(), gets called only once.

Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Reported-by: Eric Sesterhenn <snakebyte@gmx.de>

1 files changed, 13 insertions, 5 deletions

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index c350057087dd..07b6c5dfb4b6 100644
--- a/fs/jfs/jfs_metapage.c
+++ b/fs/jfs/jfs_metapage.c
@@ -369,6 +369,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
         unsigned long bio_bytes = 0;
         unsigned long bio_offset = 0;
         int offset;
+        int bad_blocks = 0;
 
         page_start = (sector_t)page->index <<
                      (PAGE_CACHE_SHIFT - inode->i_blkbits);
@@ -394,6 +395,7 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
                 }
 
                 clear_bit(META_dirty, &mp->flag);
+                set_bit(META_io, &mp->flag);
                 block_offset = offset >> inode->i_blkbits;
                 lblock = page_start + block_offset;
                 if (bio) {
@@ -402,7 +404,6 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
                                 len = min(xlen, blocks_per_mp);
                                 xlen -= len;
                                 bio_bytes += len << inode->i_blkbits;
-                                set_bit(META_io, &mp->flag);
                                 continue;
                         }
                         /* Not contiguous */
@@ -424,12 +425,14 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
                 xlen = (PAGE_CACHE_SIZE - offset) >> inode->i_blkbits;
                 pblock = metapage_get_blocks(inode, lblock, &xlen);
                 if (!pblock) {
-                        /* Need better error handling */
                         printk(KERN_ERR "JFS: metapage_get_blocks failed\n");
-                        dec_io(page, last_write_complete);
+                        /*
+                         * We already called inc_io(), but can't cancel it
+                         * with dec_io() until we're done with the page
+                         */
+                        bad_blocks++;
                         continue;
                 }
-                set_bit(META_io, &mp->flag);
                 len = min(xlen, (int)JFS_SBI(inode->i_sb)->nbperpage);
 
                 bio = bio_alloc(GFP_NOFS, 1);
@@ -459,6 +462,9 @@ static int metapage_writepage(struct page *page, struct writeback_control *wbc)
 
         unlock_page(page);
 
+        if (bad_blocks)
+                goto err_out;
+
         if (nr_underway == 0)
                 end_page_writeback(page);
 
@@ -474,7 +480,9 @@ skip:
         bio_put(bio);
         unlock_page(page);
         dec_io(page, last_write_complete);
-
+err_out:
+        while (bad_blocks--)
+                dec_io(page, last_write_complete);
         return -EIO;
 }