From: Dave Chinner dchinner@redhat.com
commit 7684e2c4384d5d1f884b01ab8bff2369e4db0bff upstream.
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.
Fixes: 3460cac1ca76 ("iomap: Use FUA for pure data O_DSYNC DIO writes") Signed-off-by: Dave Chinner dchinner@redhat.com Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Darrick J. Wong darrick.wong@oracle.com [darrick: removed the ext4 part; they'll handle it separately] Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Acked-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Chandan Babu R chandan.babu@oracle.com --- fs/xfs/xfs_iomap.c | 7 +++++++ include/linux/iomap.h | 2 ++ 2 files changed, 9 insertions(+)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 239c9548b156..26cf811f3d96 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -1055,6 +1055,13 @@ xfs_file_iomap_begin( trace_xfs_iomap_alloc(ip, offset, length, XFS_DATA_FORK, &imap);
out_finish: + /* + * Writes that span EOF might trigger an IO size update on completion, + * so consider them to be dirty for the purposes of O_DSYNC even if + * there is no other metadata changes pending or have been made here. + */ + if ((flags & IOMAP_WRITE) && offset + length > i_size_read(inode)) + iomap->flags |= IOMAP_F_DIRTY; return xfs_bmbt_to_iomap(ip, iomap, &imap, shared);
out_found: diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 53b16f104081..74e05e7b67f5 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -32,6 +32,8 @@ struct vm_fault; * * IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access * written data and requires fdatasync to commit them to persistent storage. + * This needs to take into account metadata changes that *may* be made at IO + * completion, such as file size updates from direct IO. */ #define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */ #define IOMAP_F_DIRTY 0x02 /* uncommitted metadata */