This is a note to let you know that I've just added the patch titled ext4: iomap that extends beyond EOF should be marked dirty to the 4.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-iomap-that-extends-beyond-eof-should-be-marked-.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 9a9e106c3c12f046afcba89be3188601be682a93 Author: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx> Date: Tue Nov 5 22:59:37 2019 +1100 ext4: iomap that extends beyond EOF should be marked dirty [ Upstream commit 2e9b51d78229d5145725a481bb5464ebc0a3f9b2 ] This patch addresses what Dave Chinner had discovered and fixed within commit: 7684e2c4384d. This changes does not have any user visible impact for ext4 as none of the current users of ext4_iomap_begin() that extend files depend on IOMAP_F_DIRTY. When doing a direct IO that spans the current EOF, and there are written blocks beyond EOF that extend beyond the current write, the only metadata update that needs to be done is a file size extension. However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that there is IO completion metadata updates required, and hence we may fail to correctly sync file size extensions made in IO completion when O_DSYNC writes are being used and the hardware supports FUA. Hence when setting IOMAP_F_DIRTY, we need to also take into account whether the iomap spans the current EOF. If it does, then we need to mark it dirty so that IO completion will call generic_write_sync() to flush the inode size update to stable storage correctly. Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Reviewed-by: Ritesh Harjani <riteshh@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/8b43ee9ee94bee5328da56ba0909b7d2229ef150.1572949325.git.mbobrowski@xxxxxxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 00d0c4b8fa30..950e3dcff7b0 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3544,8 +3544,14 @@ retry: return ret; } + /* + * Writes that span EOF might trigger an I/O size update on completion, + * so consider them to be dirty for the purposes of O_DSYNC, even if + * there is no other metadata changes being made or are pending here. + */ iomap->flags = 0; - if (ext4_inode_datasync_dirty(inode)) + if (ext4_inode_datasync_dirty(inode) || + offset + length > i_size_read(inode)) iomap->flags |= IOMAP_F_DIRTY; iomap->bdev = inode->i_sb->s_bdev; iomap->dax_dev = sbi->s_daxdev;