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authorwangguang <wang.guang55@zte.com.cn>2016-09-15 11:32:46 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-09-15 11:32:46 -0400
commit4e800c0359d9a53e6bf0ab216954971b2515247f (patch)
tree4f3db0d503f941d80cc55810da3954400575a274 /fs/ext4
parente22834f0248d0fa841ead6436d6c19f65539dc9c (diff)
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>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/inode.c2
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);
}