Hi backports team, Could you please apply the below patch to the 3.14-stable tree ? Thanks. Best regards Weller HUANG > -----Original Message----- > From: gregkh@xxxxxxxxxxxxxxxxxxx [mailto:gregkh@xxxxxxxxxxxxxxxxxxx] > Sent: Sunday, June 05, 2016 5:47 AM > To: jack@xxxxxxx; HUANG Weller (CM/ESW12-CN) > <Weller.Huang@xxxxxxxxxxxx>; tytso@xxxxxxx > Cc: stable@xxxxxxxxxxxxxxx > Subject: FAILED: patch "[PATCH] ext4: fix data exposure after a crash" failed to > apply to 3.14-stable tree > > > The patch below does not apply to the 3.14-stable tree. > If someone wants it applied there, or to any other stable or longterm tree, then > please email the backport, including the original git commit id to > <stable@xxxxxxxxxxxxxxx>. > > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From 06bd3c36a733ac27962fea7d6f47168841376824 Mon Sep 17 00:00:00 2001 > From: Jan Kara <jack@xxxxxxx> > Date: Sun, 24 Apr 2016 00:56:03 -0400 > Subject: [PATCH] ext4: fix data exposure after a crash > > Huang has reported that in his powerfail testing he is seeing stale block contents in > some of recently allocated blocks although he mounts > ext4 in data=ordered mode. After some investigation I have found out that indeed > when delayed allocation is used, we don't add inode to transaction's list of inodes > needing flushing before commit. Originally we were doing that but commit > f3b59291a69d removed the logic with a flawed argument that it is not needed. > > The problem is that although for delayed allocated blocks we write their contents > immediately after allocating them, there is no guarantee that the IO scheduler or > device doesn't reorder things and thus transaction allocating blocks and attaching > them to inode can reach stable storage before actual block contents. Actually > whenever we attach freshly allocated blocks to inode using a written extent, we > should add inode to transaction's ordered inode list to make sure we properly wait > for block contents to be written before committing the transaction. So that is what > we do in this patch. This also handles other cases where stale data exposure was > possible - like filling hole via mmap in data=ordered,nodelalloc mode. > > The only exception to the above rule are extending direct IO writes where > blkdev_direct_IO() waits for IO to complete before increasing i_size and thus stale > data exposure is not possible. For now we don't complicate the code with > optimizing this special case since the overhead is pretty low. In case this is > observed to be a performance problem we can always handle it using a special > flag to ext4_map_blocks(). > > CC: stable@xxxxxxxxxxxxxxx > Fixes: f3b59291a69d0b734be1fc8be489fef2dd846d3d > Reported-by: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@xxxxxxxxxxxx> > Tested-by: "HUANG Weller (CM/ESW12-CN)" <Weller.Huang@xxxxxxxxxxxx> > Signed-off-by: Jan Kara <jack@xxxxxxx> > Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 981a1fc30eaa..250c2df04a92 > 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -684,6 +684,21 @@ out_sem: > ret = check_block_validity(inode, map); > if (ret != 0) > return ret; > + > + /* > + * Inodes with freshly allocated blocks where contents will be > + * visible after transaction commit must be on transaction's > + * ordered data list. > + */ > + if (map->m_flags & EXT4_MAP_NEW && > + !(map->m_flags & EXT4_MAP_UNWRITTEN) && > + !(flags & EXT4_GET_BLOCKS_ZERO) && > + !IS_NOQUOTA(inode) && > + ext4_should_order_data(inode)) { > + ret = ext4_jbd2_file_inode(handle, inode); > + if (ret) > + return ret; > + } > } > return retval; > } > @@ -1289,15 +1304,6 @@ static int ext4_write_end(struct file *file, > int i_size_changed = 0; > > trace_ext4_write_end(inode, pos, len, copied); > - if (ext4_test_inode_state(inode, EXT4_STATE_ORDERED_MODE)) { > - ret = ext4_jbd2_file_inode(handle, inode); > - if (ret) { > - unlock_page(page); > - put_page(page); > - goto errout; > - } > - } > - > if (ext4_has_inline_data(inode)) { > ret = ext4_write_inline_data_end(inode, pos, len, > copied, page); -- To unsubscribe from this list: send the line "unsubscribe backports" in
