From 172ed391f6e40f799273e005405041b57c343cf7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 1 Mar 2018 14:10:31 -0800 Subject: xfs: don't allocate COW blocks for zeroing holes or unwritten extents The iomap zeroing interface is smart enough to skip zeroing holes or unwritten extents. Don't subvert this logic for reflink files. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_iomap.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 66e1edbfb2b2..4e771e0f1170 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -955,6 +955,13 @@ static inline bool imap_needs_alloc(struct inode *inode, (IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN); } +static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps) +{ + return nimaps && + imap->br_startblock != HOLESTARTBLOCK && + imap->br_state != XFS_EXT_UNWRITTEN; +} + static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) { /* @@ -1024,7 +1031,9 @@ xfs_file_iomap_begin( goto out_unlock; } - if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) { + if (xfs_is_reflink_inode(ip) && + ((flags & IOMAP_WRITE) || + ((flags & IOMAP_ZERO) && needs_cow_for_zeroing(&imap, nimaps)))) { if (flags & IOMAP_DIRECT) { /* * A reflinked inode will result in CoW alloc. -- cgit v1.2.3 From af5b5afe9ac68406892fa343fafba4ea988c3c69 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 1 Mar 2018 14:12:12 -0800 Subject: xfs: don't start out with the exclusive ilock for direct I/O There is no reason to take the ilock exclusively at the start of xfs_file_iomap_begin for direct I/O, given that it will be demoted just before calling xfs_iomap_write_direct anyway. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_iomap.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 4e771e0f1170..ee01859b77a5 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -965,13 +965,11 @@ static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps) static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) { /* - * COW writes will allocate delalloc space, so we need to make sure - * to take the lock exclusively here. + * COW writes may allocate delalloc space or convert unwritten COW + * extents, so we need to make sure to take the lock exclusively here. */ if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO))) return true; - if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE)) - return true; return false; } -- cgit v1.2.3 From ff3d8b9c4cb95180ae6ef9eed28409840525b9fa Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 1 Mar 2018 14:12:45 -0800 Subject: xfs: don't block on the ilock for RWF_NOWAIT Fix xfs_file_iomap_begin to trylock the ilock if IOMAP_NOWAIT is passed, so that we don't block io_submit callers. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_iomap.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index ee01859b77a5..046469fcc1b8 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -970,6 +970,15 @@ static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags) */ if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO))) return true; + + /* + * Extents not yet cached requires exclusive access, don't block. + * This is an opencoded xfs_ilock_data_map_shared() to cater for the + * non-blocking behaviour. + */ + if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE && + !(ip->i_df.if_flags & XFS_IFEXTENTS)) + return true; return false; } @@ -998,16 +1007,18 @@ xfs_file_iomap_begin( return xfs_file_iomap_begin_delay(inode, offset, length, iomap); } - if (need_excl_ilock(ip, flags)) { + if (need_excl_ilock(ip, flags)) lockmode = XFS_ILOCK_EXCL; - xfs_ilock(ip, XFS_ILOCK_EXCL); - } else { - lockmode = xfs_ilock_data_map_shared(ip); - } + else + lockmode = XFS_ILOCK_SHARED; - if ((flags & IOMAP_NOWAIT) && !(ip->i_df.if_flags & XFS_IFEXTENTS)) { - error = -EAGAIN; - goto out_unlock; + if (flags & IOMAP_NOWAIT) { + if (!(ip->i_df.if_flags & XFS_IFEXTENTS)) + return -EAGAIN; + if (!xfs_ilock_nowait(ip, lockmode)) + return -EAGAIN; + } else { + xfs_ilock(ip, lockmode); } ASSERT(offset <= mp->m_super->s_maxbytes); -- cgit v1.2.3