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| author | Eric Sandeen <sandeen@redhat.com> | 2010-10-28 03:30:13 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2010-10-28 03:30:13 +0200 |
| commit | 72f84e6560d18d60a091df27edf81409be6641cb (patch) | |
| tree | e2fa11476b074f8526d620820f8b2e86e8a11412 | |
| parent | ext4: implement writeback livelock avoidance using page tagging (diff) | |
| download | linux-72f84e6560d18d60a091df27edf81409be6641cb.tar.xz linux-72f84e6560d18d60a091df27edf81409be6641cb.zip | |
ext4: update writeback_index based on last page scanned
As pointed out in a prior patch, updating the mapping's
writeback_index based on pages written isn't quite right;
what the writeback index is really supposed to reflect is
the next page which should be scanned for writeback during
periodic flush.
As in write_cache_pages(), write_cache_pages_da() does
this scanning for us as we assemble the mpd for later
writeout. If we keep track of the next page after the
current scan, we can easily update writeback_index without
worrying about pages written vs. pages skipped, etc.
Without this, an fsync will reset writeback_index to
0 (its starting index) + however many pages it wrote, which
can mess up the progress of periodic flush.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c9ea95ba5fde..45fc5bdb7d67 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2800,12 +2800,13 @@ static int ext4_da_writepages_trans_blocks(struct inode *inode) */ static int write_cache_pages_da(struct address_space *mapping, struct writeback_control *wbc, - struct mpage_da_data *mpd) + struct mpage_da_data *mpd, + pgoff_t *done_index) { int ret = 0; int done = 0; struct pagevec pvec; - int nr_pages; + unsigned nr_pages; pgoff_t index; pgoff_t end; /* Inclusive */ long nr_to_write = wbc->nr_to_write; @@ -2820,6 +2821,7 @@ static int write_cache_pages_da(struct address_space *mapping, else tag = PAGECACHE_TAG_DIRTY; + *done_index = index; while (!done && (index <= end)) { int i; @@ -2843,6 +2845,8 @@ static int write_cache_pages_da(struct address_space *mapping, break; } + *done_index = page->index + 1; + lock_page(page); /* @@ -2928,6 +2932,7 @@ static int ext4_da_writepages(struct address_space *mapping, long desired_nr_to_write, nr_to_writebump = 0; loff_t range_start = wbc->range_start; struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); + pgoff_t done_index = 0; pgoff_t end; trace_ext4_da_writepages(inode, wbc); @@ -3050,7 +3055,7 @@ retry: mpd.io_done = 0; mpd.pages_written = 0; mpd.retval = 0; - ret = write_cache_pages_da(mapping, wbc, &mpd); + ret = write_cache_pages_da(mapping, wbc, &mpd, &done_index); /* * If we have a contiguous extent of pages and we * haven't done the I/O yet, map the blocks and submit @@ -3104,14 +3109,13 @@ retry: __func__, wbc->nr_to_write, ret); /* Update index */ - index += pages_written; wbc->range_cyclic = range_cyclic; if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) /* * set the writeback_index so that range_cyclic * mode will write it back later */ - mapping->writeback_index = index; + mapping->writeback_index = done_index; out_writepages: wbc->nr_to_write -= nr_to_writebump; |