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authorwangguang <wang.guang55@zte.com.cn>2016-09-15 11:32:46 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-24 09:32:11 +0200
commita529f29a3ea9cb7e2c90053c02c8213f527374df (patch)
tree034b5f621e1a5379bcd4bcc2e8fc19343595a786 /fs/ext4/inode.c
parentd47a5ca386aaa6b8d17c7b8cdbdc7d2631c68278 (diff)
ext4: bugfix for mmaped pages in mpage_release_unused_pages()
commit 4e800c0359d9a53e6bf0ab216954971b2515247f upstream. 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> [@nathanchance: Resolved conflict from lack of 09cbfeaf1a5a6] Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4/inode.c')
-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 2c056a529a37..56ce7fd0f0d0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1515,6 +1515,8 @@ 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_CACHE_SIZE);
ClearPageUptodate(page);
}