ext4: remove page_skipped hackery in ext4_da_writepages()

Because the ext4 page writeback codepath had been prematurely calling
clear_page_dirty_for_io(), if it turned out that a particular page
couldn't be written out during a particular pass of
write_cache_pages_da(), the page would have to get redirtied by
calling redirty_pages_for_writeback().  Not only was this wasted work,
but redirty_page_for_writeback() would increment wbc->pages_skipped to
signal to writeback_sb_inodes() that buffers were locked, and that it
should skip this inode until later.

Since this signal was incorrect in ext4's case --- which was caused by
ext4's historically incorrect use of write_cache_pages() ---
ext4_da_writepages() saved and restored wbc->skipped_pages to avoid
confusing writeback_sb_inodes().

Now that we've fixed ext4 to call clear_page_dirty_for_io() right
before initiating the page I/O, we can nuke the page_skipped
save/restore hackery, and breathe a sigh of relief.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 0 insertions, 10 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ae6e2f43d873..617c9cbba182 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2900,7 +2900,6 @@ static int ext4_da_writepages(struct address_space *mapping,
         struct mpage_da_data mpd;
         struct inode *inode = mapping->host;
         int pages_written = 0;
-        long pages_skipped;
         unsigned int max_pages;
         int range_cyclic, cycled = 1, io_done = 0;
         int needed_blocks, ret = 0;
@@ -2986,8 +2985,6 @@ static int ext4_da_writepages(struct address_space *mapping,
         mpd.wbc = wbc;
         mpd.inode = mapping->host;
 
-        pages_skipped = wbc->pages_skipped;
-
 retry:
         if (wbc->sync_mode == WB_SYNC_ALL)
                 tag_pages_for_writeback(mapping, index, end);
@@ -3047,7 +3044,6 @@ retry:
                          * and try again
                          */
                         jbd2_journal_force_commit_nested(sbi->s_journal);
-                        wbc->pages_skipped = pages_skipped;
                         ret = 0;
                 } else if (ret == MPAGE_DA_EXTENT_TAIL) {
                         /*
@@ -3055,7 +3051,6 @@ retry:
                          * rest of the pages
                          */
                         pages_written += mpd.pages_written;
-                        wbc->pages_skipped = pages_skipped;
                         ret = 0;
                         io_done = 1;
                 } else if (wbc->nr_to_write)
@@ -3073,11 +3068,6 @@ retry:
                 wbc->range_end  = mapping->writeback_index - 1;
                 goto retry;
         }
-        if (pages_skipped != wbc->pages_skipped)
-                ext4_msg(inode->i_sb, KERN_CRIT,
-                         "This should not happen leaving %s "
-                         "with nr_to_write = %ld ret = %d",
-                         __func__, wbc->nr_to_write, ret);
 
         /* Update index */
         wbc->range_cyclic = range_cyclic;