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>

diff --git a/fs/jfs/jfs_metapage.c b/fs/jfs/jfs_metapage.c
index c350057..07b6c5d 100644 (file)
--- 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;
 }