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| author | wangguang <wang.guang55@zte.com.cn> | 2016-09-15 17:32:46 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-09-15 17:32:46 +0200 |
| commit | 4e800c0359d9a53e6bf0ab216954971b2515247f (patch) | |
| tree | 4f3db0d503f941d80cc55810da3954400575a274 | |
| parent | ext4: improve ext4lazyinit scalability (diff) | |
| download | linux-4e800c0359d9a53e6bf0ab216954971b2515247f.tar.xz linux-4e800c0359d9a53e6bf0ab216954971b2515247f.zip | |
ext4: bugfix for mmaped pages in mpage_release_unused_pages()
Pages clear buffers after ext4 delayed block allocation failed,
However, it does not clean its pte_dirty flag.
if the pages unmap ,in cording to the pte_dirty ,
unmap_page_range may try to call __set_page_dirty,
which may lead to the bugon at
mpage_prepare_extent_to_map:head = page_buffers(page);.
This patch just call clear_page_dirty_for_io to clean pte_dirty
at mpage_release_unused_pages for pages mmaped.
Steps to reproduce the bug:
（1） mmap a file in ext4
addr = (char *)mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED,
fd, 0);
memset(addr, 'i', 4096);
（2） return EIO at
ext4_writepages->mpage_map_and_submit_extent->mpage_map_one_extent
which causes this log message to be print:
ext4_msg(sb, KERN_CRIT,
"Delayed block allocation failed for "
"inode %lu at logical offset %llu with"
" max blocks %u with error %d",
inode->i_ino,
(unsigned long long)map->m_lblk,
(unsigned)map->m_len, -err);
(3）Unmap the addr cause warning at
__set_page_dirty:WARN_ON_ONCE(warn && !PageUptodate(page));
(4) wait for a minute,then bugon happen.
Cc: stable@vger.kernel.org
Signed-off-by: wangguang <wangguang03@zte.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f058afbc4c46..9b464e5272bb 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1649,6 +1649,8 @@ static void mpage_release_unused_pages(struct mpage_da_data *mpd, BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); if (invalidate) { + if (page_mapped(page)) + clear_page_dirty_for_io(page); block_invalidatepage(page, 0, PAGE_SIZE); ClearPageUptodate(page); } |