From: Goldwyn Rodrigues <rgoldwyn@suse.de> To: linux-fsdevel@vger.kernel.org Cc: jack@suse.com, hch@infradead.org, linux-block@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, axboe@kernel.dk, linux-api@vger.kernel.org, adam.manzanares@wdc.com, viro@zeniv.linux.org.uk, Goldwyn Rodrigues <rgoldwyn@suse.com> Subject: [PATCH 05/10] fs: return if direct write will trigger writeback Date: Wed, 24 May 2017 11:41:45 -0500 [thread overview] Message-ID: <20170524164150.9492-6-rgoldwyn@suse.de> (raw) In-Reply-To: <20170524164150.9492-1-rgoldwyn@suse.de> From: Goldwyn Rodrigues <rgoldwyn@suse.com> Find out if the write will trigger a wait due to writeback. If yes, return -EAGAIN. Return -EINVAL for buffered AIO: there are multiple causes of delay such as page locks, dirty throttling logic, page loading from disk etc. which cannot be taken care of. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: Christoph Hellwig <hch@lst.de> --- mm/filemap.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 097213275461..bc146efa6815 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) pos = iocb->ki_pos; + if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) + return -EINVAL; + if (limit != RLIM_INFINITY) { if (iocb->ki_pos >= limit) { send_sig(SIGXFSZ, current, 0); @@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) write_len = iov_iter_count(from); end = (pos + write_len - 1) >> PAGE_SHIFT; - written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); - if (written) - goto out; + if (iocb->ki_flags & IOCB_NOWAIT) { + /* If there are pages to writeback, return */ + if (filemap_range_has_page(inode->i_mapping, pos, + pos + iov_iter_count(from))) + return -EAGAIN; + } else { + written = filemap_write_and_wait_range(mapping, pos, + pos + write_len - 1); + if (written) + goto out; + } /* * After a write we want buffered reads to be sure to go to disk to get -- 2.12.0
WARNING: multiple messages have this Message-ID (diff)
From: Goldwyn Rodrigues <rgoldwyn-l3A5Bk7waGM@public.gmane.org> To: linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: jack-IBi9RG/b67k@public.gmane.org, hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-xfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, adam.manzanares-Sjgp3cTcYWE@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, Goldwyn Rodrigues <rgoldwyn-IBi9RG/b67k@public.gmane.org> Subject: [PATCH 05/10] fs: return if direct write will trigger writeback Date: Wed, 24 May 2017 11:41:45 -0500 [thread overview] Message-ID: <20170524164150.9492-6-rgoldwyn@suse.de> (raw) In-Reply-To: <20170524164150.9492-1-rgoldwyn-l3A5Bk7waGM@public.gmane.org> From: Goldwyn Rodrigues <rgoldwyn-IBi9RG/b67k@public.gmane.org> Find out if the write will trigger a wait due to writeback. If yes, return -EAGAIN. Return -EINVAL for buffered AIO: there are multiple causes of delay such as page locks, dirty throttling logic, page loading from disk etc. which cannot be taken care of. Signed-off-by: Goldwyn Rodrigues <rgoldwyn-IBi9RG/b67k@public.gmane.org> Reviewed-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> --- mm/filemap.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 097213275461..bc146efa6815 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2675,6 +2675,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) pos = iocb->ki_pos; + if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) + return -EINVAL; + if (limit != RLIM_INFINITY) { if (iocb->ki_pos >= limit) { send_sig(SIGXFSZ, current, 0); @@ -2743,9 +2746,17 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) write_len = iov_iter_count(from); end = (pos + write_len - 1) >> PAGE_SHIFT; - written = filemap_write_and_wait_range(mapping, pos, pos + write_len - 1); - if (written) - goto out; + if (iocb->ki_flags & IOCB_NOWAIT) { + /* If there are pages to writeback, return */ + if (filemap_range_has_page(inode->i_mapping, pos, + pos + iov_iter_count(from))) + return -EAGAIN; + } else { + written = filemap_write_and_wait_range(mapping, pos, + pos + write_len - 1); + if (written) + goto out; + } /* * After a write we want buffered reads to be sure to go to disk to get -- 2.12.0
next prev parent reply other threads:[~2017-05-24 16:41 UTC|newest] Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-05-24 16:41 [PATCH 0/10 v9] No wait AIO Goldwyn Rodrigues 2017-05-24 16:41 ` [PATCH 01/10] fs: Separate out kiocb flags setup based on RWF_* flags Goldwyn Rodrigues 2017-05-25 8:16 ` Jan Kara 2017-05-24 16:41 ` [PATCH 02/10] fs: Introduce filemap_range_has_page() Goldwyn Rodrigues 2017-05-25 8:25 ` Jan Kara 2017-05-24 16:41 ` [PATCH 03/10] fs: Use RWF_* flags for AIO operations Goldwyn Rodrigues 2017-05-24 16:41 ` Goldwyn Rodrigues 2017-05-25 8:27 ` Jan Kara 2017-05-24 16:41 ` [PATCH 04/10] fs: Introduce RWF_NOWAIT Goldwyn Rodrigues 2017-05-25 8:30 ` Jan Kara 2017-05-24 16:41 ` Goldwyn Rodrigues [this message] 2017-05-24 16:41 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues 2017-05-25 8:32 ` Jan Kara 2017-05-24 16:41 ` [PATCH 06/10] fs: Introduce IOMAP_NOWAIT Goldwyn Rodrigues 2017-05-25 8:33 ` Jan Kara 2017-05-24 16:41 ` [PATCH 07/10] fs: return on congested block device Goldwyn Rodrigues 2017-05-24 16:41 ` [PATCH 08/10] ext4: nowait aio support Goldwyn Rodrigues 2017-05-24 16:41 ` [PATCH 09/10] xfs: " Goldwyn Rodrigues 2017-05-24 16:49 ` Darrick J. Wong 2017-05-28 9:31 ` Christoph Hellwig 2017-05-28 9:31 ` Christoph Hellwig 2017-05-29 2:38 ` Goldwyn Rodrigues 2017-05-29 8:21 ` Jan Kara 2017-05-29 8:33 ` Christoph Hellwig 2017-05-30 16:13 ` Goldwyn Rodrigues 2017-05-30 16:13 ` Goldwyn Rodrigues 2017-05-31 8:51 ` Jan Kara 2017-05-24 16:41 ` [PATCH 10/10] btrfs: " Goldwyn Rodrigues 2017-05-28 9:27 ` [PATCH 0/10 v9] No wait AIO Christoph Hellwig 2017-05-28 9:27 ` Christoph Hellwig 2017-05-29 2:38 ` Goldwyn Rodrigues 2017-05-29 8:32 ` Christoph Hellwig -- strict thread matches above, loose matches on Subject: below -- 2017-06-15 15:59 [PATCH 0/10 v12] " Goldwyn Rodrigues 2017-06-15 15:59 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues 2017-06-06 11:19 [PATCH 0/10 v11] No wait AIO Goldwyn Rodrigues 2017-06-06 11:19 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues 2017-06-05 5:35 [PATCH 0/10 v10] No wait AIO Goldwyn Rodrigues 2017-06-05 5:35 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues 2017-05-11 19:17 [PATCH 0/10 v8] No wait AIO Goldwyn Rodrigues 2017-05-11 19:17 ` [PATCH 05/10] fs: return if direct write will trigger writeback Goldwyn Rodrigues
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