| Message ID | 20200622152457.7118-3-rgoldwyn@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs direct-io using iomap | expand |
On Mon, Jun 22, 2020 at 10:24:53AM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > The flag indicates that if the page invalidation fails, it should return > back control to the filesystem so it may fallback to buffered mode. > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Looks reasonable enough, I suppose... Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> --D > --- > fs/iomap/direct-io.c | 8 +++++++- > include/linux/iomap.h | 5 +++++ > 2 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 7ed857196a39..20c4370e6b1b 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_DIOF_PGINVALID_FAIL) { > + 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 f6230446b08d..95024e28dec5 100644 > --- a/include/linux/iomap.h > +++ b/include/linux/iomap.h > @@ -261,6 +261,11 @@ struct iomap_dio_ops { > > /* Wait for completion of DIO */ > #define IOMAP_DIOF_WAIT_FOR_COMPLETION 0x1 > +/* > + * Return zero if page invalidation fails, so caller filesystem may fallback > + * to buffered I/O > + */ > +#define IOMAP_DIOF_PGINVALID_FAIL 0x2 > > ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > const struct iomap_ops *ops, const struct iomap_dio_ops *dops, > -- > 2.25.0 >
On Mon, Jun 22, 2020 at 10:33:30AM -0700, Darrick J. Wong wrote: > On Mon, Jun 22, 2020 at 10:24:53AM -0500, Goldwyn Rodrigues wrote: > > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > > The flag indicates that if the page invalidation fails, it should return > > back control to the filesystem so it may fallback to buffered mode. > > > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > Looks reasonable enough, I suppose... > > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > --D > > > --- > > fs/iomap/direct-io.c | 8 +++++++- > > include/linux/iomap.h | 5 +++++ > > 2 files changed, 12 insertions(+), 1 deletion(-) > > > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > > index 7ed857196a39..20c4370e6b1b 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_DIOF_PGINVALID_FAIL) { > > + 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 f6230446b08d..95024e28dec5 100644 > > --- a/include/linux/iomap.h > > +++ b/include/linux/iomap.h > > @@ -261,6 +261,11 @@ struct iomap_dio_ops { > > > > /* Wait for completion of DIO */ > > #define IOMAP_DIOF_WAIT_FOR_COMPLETION 0x1 > > +/* > > + * Return zero if page invalidation fails, so caller filesystem may fallback > > + * to buffered I/O > > + */ > > +#define IOMAP_DIOF_PGINVALID_FAIL 0x2 That's a mouthful of letter salad. :( Basically, you want the DIO to return a short IO if there is a busy page cache on the inode? IOWs, you don't want the page cache to become stale as a result of the DIO being executed? So what the caller is actually asking for is that the dio avoids creating stale page cache pages? Hence: /* * 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 resubmit the entire IO as a * buffered IO through the page cache. */ #define IOMAP_DIO_RWF_NO_STALE_PAGECACHE (1 << 1) Cheers, Dave.
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 7ed857196a39..20c4370e6b1b 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_DIOF_PGINVALID_FAIL) { + 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 f6230446b08d..95024e28dec5 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -261,6 +261,11 @@ struct iomap_dio_ops { /* Wait for completion of DIO */ #define IOMAP_DIOF_WAIT_FOR_COMPLETION 0x1 +/* + * Return zero if page invalidation fails, so caller filesystem may fallback + * to buffered I/O + */ +#define IOMAP_DIOF_PGINVALID_FAIL 0x2 ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops,