summaryrefslogtreecommitdiffstats
path: root/fs/ext4/ext4_jbd2.c
diff options
context:
space:
mode:
authorzhangyi (F) <yi.zhang@huawei.com>2020-06-20 04:54:23 +0200
committerTheodore Ts'o <tytso@mit.edu>2020-08-07 20:12:34 +0200
commitbc71726c725767205757821df364acff87f92ac5 (patch)
tree091fcc3c180953f83a0e6627902ece509e34f109 /fs/ext4/ext4_jbd2.c
parentext4: skip non-loaded groups at cr=0/1 when scanning for good groups (diff)
downloadlinux-bc71726c725767205757821df364acff87f92ac5.tar.xz
linux-bc71726c725767205757821df364acff87f92ac5.zip
ext4: abort the filesystem if failed to async write metadata buffer
There is a risk of filesystem inconsistency if we failed to async write back metadata buffer in the background. Because of current buffer's end io procedure is handled by end_buffer_async_write() in the block layer, and it only clear the buffer's uptodate flag and mark the write_io_error flag, so ext4 cannot detect such failure immediately. In most cases of getting metadata buffer (e.g. ext4_read_inode_bitmap()), although the buffer's data is actually uptodate, it may still read data from disk because the buffer's uptodate flag has been cleared. Finally, it may lead to on-disk filesystem inconsistency if reading old data from the disk successfully and write them out again. This patch detect bdev mapping->wb_err when getting journal's write access and mark the filesystem error if bdev's mapping->wb_err was increased, this could prevent further writing and potential inconsistency. Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> Suggested-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20200620025427.1756360-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ext4_jbd2.c')
-rw-r--r--fs/ext4/ext4_jbd2.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
index 0c76cdd44d90..760b9ee49dc0 100644
--- a/fs/ext4/ext4_jbd2.c
+++ b/fs/ext4/ext4_jbd2.c
@@ -195,6 +195,28 @@ static void ext4_journal_abort_handle(const char *caller, unsigned int line,
jbd2_journal_abort_handle(handle);
}
+static void ext4_check_bdev_write_error(struct super_block *sb)
+{
+ struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+ struct ext4_sb_info *sbi = EXT4_SB(sb);
+ int err;
+
+ /*
+ * If the block device has write error flag, it may have failed to
+ * async write out metadata buffers in the background. In this case,
+ * we could read old data from disk and write it out again, which
+ * may lead to on-disk filesystem inconsistency.
+ */
+ if (errseq_check(&mapping->wb_err, READ_ONCE(sbi->s_bdev_wb_err))) {
+ spin_lock(&sbi->s_bdev_wb_lock);
+ err = errseq_check_and_advance(&mapping->wb_err, &sbi->s_bdev_wb_err);
+ spin_unlock(&sbi->s_bdev_wb_lock);
+ if (err)
+ ext4_error_err(sb, -err,
+ "Error while async write back metadata");
+ }
+}
+
int __ext4_journal_get_write_access(const char *where, unsigned int line,
handle_t *handle, struct buffer_head *bh)
{
@@ -202,6 +224,9 @@ int __ext4_journal_get_write_access(const char *where, unsigned int line,
might_sleep();
+ if (bh->b_bdev->bd_super)
+ ext4_check_bdev_write_error(bh->b_bdev->bd_super);
+
if (ext4_handle_valid(handle)) {
err = jbd2_journal_get_write_access(handle, bh);
if (err)