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Message-Id: <20200708211926.7706-3-rgoldwyn@suse.de> Date: Wed, 8 Jul 2020 16:19:22 -0500 From: Goldwyn Rodrigues <rgoldwyn@...e.de> To: linux-btrfs@...r.kernel.org Cc: linux-fsdevel@...r.kernel.org, darrick.wong@...cle.com, hch@....de, cluster-devel@...hat.com, linux-ext4@...r.kernel.org, linux-xfs@...r.kernel.org, Goldwyn Rodrigues <rgoldwyn@...e.com> Subject: [PATCH 2/6] iomap: IOMAP_DIO_RWF_NO_STALE_PAGECACHE return if page invalidation fails From: Goldwyn Rodrigues <rgoldwyn@...e.com> For direct I/O, add the flag IOMAP_DIO_RWF_NO_STALE_PAGECACHE to indicate that if the page invalidation fails, return back control to the filesystem so it may fallback to buffered mode. Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@...e.com> --- fs/iomap/direct-io.c | 8 +++++++- include/linux/iomap.h | 14 ++++++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 2753b7022403..66becf935865 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -484,8 +484,14 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, */ ret = invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT); - if (ret) + if (ret) { + if (dio_flags & IOMAP_DIO_RWF_NO_STALE_PAGECACHE) { + if (ret == -EBUSY) + ret = 0; + goto out_free_dio; + } dio_warn_stale_pagecache(iocb->ki_filp); + } ret = 0; if (iov_iter_rw(iter) == WRITE && !wait_for_completion && diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 80cd5f524124..a68705369a2c 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -262,7 +262,21 @@ struct iomap_dio_ops { /* * Wait for completion of DIO */ + #define IOMAP_DIO_RWF_SYNCIO (1 << 0) +/* + * Direct IO will attempt to keep the page cache coherent by + * invalidating the inode's page cache over the range of the DIO. + * That can fail if something else is actively using the page cache. + * If this happens and the DIO continues, the data in the page + * cache will become stale. + * + * Set this flag if you want the DIO to abort without issuing any IO + * or error if it fails to invalidate the page cache successfully. + * This allows the IO submitter to fallback to buffered IO to resubmit + * IO + */ +#define IOMAP_DIO_RWF_NO_STALE_PAGECACHE (1 << 1) ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, -- 2.26.2
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