| Message ID | 20210118193516.2915706-12-hch@lst.de (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [01/11] xfs: factor out a xfs_ilock_iocb helper | expand |
On Mon, Jan 18, 2021 at 08:35:16PM +0100, Christoph Hellwig wrote: > From: Dave Chinner <dchinner@redhat.com> > > Attempt shared locking for unaligned DIO, but only if the the > underlying extent is already allocated and in written state. On > failure, retry with the existing exclusive locking. .... > @@ -590,19 +617,27 @@ xfs_file_dio_write_unaligned( > goto out_unlock; > > /* > - * If we are doing unaligned I/O, we can't allow any other overlapping > - * I/O in-flight at the same time or we risk data corruption. Wait for > - * all other I/O to drain before we submit. > + * If we are doing exclusive unaligned IO, we can't allow any other > + * overlapping IO in-flight at the same time or we risk data corruption. > + * Wait for all other IO to drain before we submit. > */ > - inode_dio_wait(VFS_I(ip)); > + if (!(flags & IOMAP_DIO_UNALIGNED)) > + inode_dio_wait(VFS_I(ip)); > > - /* > - * This must be the only I/O in-flight. Wait on it before we release the > - * iolock to prevent subsequent overlapping I/O. > - */ > trace_xfs_file_direct_write(iocb, from); > ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops, > - &xfs_dio_write_ops, IOMAP_DIO_FORCE_WAIT); > + &xfs_dio_write_ops, flags); > + /* > + * Retry unaligned IO with exclusive blocking semantics if the DIO > + * layer rejected it for mapping or locking reasons. If we are doing > + * nonblocking user IO, propagate the error. > + */ > + if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) { > + ASSERT(flags & IOMAP_DIO_UNALIGNED); > + xfs_iunlock(ip, iolock); > + goto retry_exclusive; > + } > + > out_unlock: > if (iolock) > xfs_iunlock(ip, iolock); Do we ever get here without holding the iolock anymore? > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index 7b9ff824e82d48..dc8c86e98b99bf 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -784,15 +784,30 @@ xfs_direct_write_iomap_begin( > goto allocate_blocks; > > /* > - * NOWAIT IO needs to span the entire requested IO with a single map so > - * that we avoid partial IO failures due to the rest of the IO range not > - * covered by this map triggering an EAGAIN condition when it is > - * subsequently mapped and aborting the IO. > + * NOWAIT and unaligned IO needs to span the entire requested IO with a > + * single map so that we avoid partial IO failures due to the rest of > + * the IO range not covered by this map triggering an EAGAIN condition > + * when it is subsequently mapped and aborting the IO. > */ > - if ((flags & IOMAP_NOWAIT) && > - !imap_spans_range(&imap, offset_fsb, end_fsb)) { > + if (flags & (IOMAP_NOWAIT | IOMAP_UNALIGNED)) { > error = -EAGAIN; > - goto out_unlock; > + if (!imap_spans_range(&imap, offset_fsb, end_fsb)) > + goto out_unlock; > + } > + > + /* > + * For unsigned I/O we can't convert an unwritten extents if the I/O is > + * not block size aligned, as such a conversion would have to do > + * sub-block zeroing, and that can only be done under an exclusive > + * IOLOCK. Hence if this is not a written extent, return EAGAIN to tell > + * the caller to try again. > + */ A few typos in that comment :) /* * For unaligned IO, we cannot convert unwritten extents without * requiring sub-block zeroing. This can only be done under an exclusive * IOLOCK, hence return -EAGAIN if this is not a written extent to tell * the caller to try again. */ Cheers, Dave.
On Tue, Jan 19, 2021 at 07:55:21AM +1100, Dave Chinner wrote: > > + &xfs_dio_write_ops, flags); > > + /* > > + * Retry unaligned IO with exclusive blocking semantics if the DIO > > + * layer rejected it for mapping or locking reasons. If we are doing > > + * nonblocking user IO, propagate the error. > > + */ > > + if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) { > > + ASSERT(flags & IOMAP_DIO_UNALIGNED); > > + xfs_iunlock(ip, iolock); > > + goto retry_exclusive; > > + } > > + > > out_unlock: > > if (iolock) > > xfs_iunlock(ip, iolock); > > Do we ever get here without holding the iolock anymore? Yes, if xfs_ilock_iocb as called from xfs_file_write_checks fails.
On Mon, Jan 18, 2021 at 08:35:16PM +0100, Christoph Hellwig wrote: > From: Dave Chinner <dchinner@redhat.com> > > Attempt shared locking for unaligned DIO, but only if the the > underlying extent is already allocated and in written state. On > failure, retry with the existing exclusive locking. > > Test case is fio randrw of 512 byte IOs using AIO and an iodepth of > 32 IOs. > > Vanilla: > > READ: bw=4560KiB/s (4670kB/s), 4560KiB/s-4560KiB/s (4670kB/s-4670kB/s), io=134MiB (140MB), run=30001-30001msec > WRITE: bw=4567KiB/s (4676kB/s), 4567KiB/s-4567KiB/s (4676kB/s-4676kB/s), io=134MiB (140MB), run=30001-30001msec > > Patched: > READ: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1127MiB (1182MB), run=30002-30002msec > WRITE: bw=37.6MiB/s (39.4MB/s), 37.6MiB/s-37.6MiB/s (39.4MB/s-39.4MB/s), io=1128MiB (1183MB), run=30002-30002msec > > That's an improvement from ~18k IOPS to a ~150k IOPS, which is > about the IOPS limit of the VM block device setup I'm testing on. > > 4kB block IO comparison: > > READ: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8868MiB (9299MB), run=30002-30002msec > WRITE: bw=296MiB/s (310MB/s), 296MiB/s-296MiB/s (310MB/s-310MB/s), io=8878MiB (9309MB), run=30002-30002msec > > Which is ~150k IOPS, same as what the test gets for sub-block > AIO+DIO writes with this patch. > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > [hch: rebased, split unaligned from nowait] > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > fs/xfs/xfs_file.c | 87 ++++++++++++++++++++++++++++++++-------------- > fs/xfs/xfs_iomap.c | 31 ++++++++++++----- > 2 files changed, 84 insertions(+), 34 deletions(-) > > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index b181db42f2f32f..4e475e750148db 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -544,22 +544,35 @@ xfs_file_dio_write_aligned( > /* > * Handle block unaligned direct IO writes > * > - * In most cases direct IO writes will be done holding IOLOCK_SHARED, allowing > - * them to be done in parallel with reads and other direct IO writes. However, > - * if the I/O is not aligned to filesystem blocks, the direct I/O layer may > - * need to do sub-block zeroing and that requires serialisation against other > - * direct I/Os to the same block. In this case we need to serialise the > - * submission of the unaligned I/Os so that we don't get racing block zeroing in > - * the dio layer. > + * In most cases direct IO writes will be done holding IOLOCK_SHARED > + * allowing them to be done in parallel with reads and other direct IO writes. > + * However, if the IO is not aligned to filesystem blocks, the direct IO layer > + * may need to do sub-block zeroing and that requires serialisation against other > + * direct IOs to the same block. In the case where sub-block zeroing is not > + * required, we can do concurrent sub-block dios to the same block successfully. > * > - * To provide the same serialisation for AIO, we also need to wait for > + * Hence we have two cases here - the shared, optimisitic fast path for written > + * extents, and everything else that needs exclusive IO path access across the > + * entire IO. > + * > + * For the first case, we do all the checks we need at the mapping layer in the > + * DIO code as part of the existing NOWAIT infrastructure. Hence all we need to > + * do to support concurrent subblock dio is first try a non-blocking submission. > + * If that returns -EAGAIN, then we simply repeat the IO submission with full > + * IO exclusivity guaranteed so that we avoid racing sub-block zeroing. > + * > + * The only wrinkle in this case is that the iomap DIO code always does > + * partial tail sub-block zeroing for post-EOF writes. Hence for any IO that > + * _ends_ past the current EOF we need to run with full exclusivity. Note that > + * we also check for the start of IO being beyond EOF because then zeroing > + * between the old EOF and the start of the IO is required and that also > + * requires exclusivity. Hence we avoid lock cycles and blocking under > + * IOCB_NOWAIT for this situation, too. > + * > + * To provide the exclusivity required when using AIO, we also need to wait for > * outstanding IOs to complete so that unwritten extent conversion is completed > * before we try to map the overlapping block. This is currently implemented by > * hitting it with a big hammer (i.e. inode_dio_wait()). > - * > - * This means that unaligned dio writes always block. There is no "nowait" fast > - * path in this code - if IOCB_NOWAIT is set we simply return -EAGAIN up front > - * and we don't have to worry about that anymore. > */ > static noinline ssize_t > xfs_file_dio_write_unaligned( > @@ -567,13 +580,27 @@ xfs_file_dio_write_unaligned( > struct kiocb *iocb, > struct iov_iter *from) > { > - int iolock = XFS_IOLOCK_EXCL; > + size_t isize = i_size_read(VFS_I(ip)); > + size_t count = iov_iter_count(from); > + int iolock = XFS_IOLOCK_SHARED; > + unsigned int flags = IOMAP_DIO_UNALIGNED; > ssize_t ret; > > - /* unaligned dio always waits, bail */ > - if (iocb->ki_flags & IOCB_NOWAIT) > - return -EAGAIN; > - xfs_ilock(ip, iolock); > + /* > + * Extending writes need exclusivity because of the sub-block zeroing > + * that the DIO code always does for partial tail blocks beyond EOF. > + */ > + if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) { > +retry_exclusive: > + if (iocb->ki_flags & IOCB_NOWAIT) > + return -EAGAIN; > + iolock = XFS_IOLOCK_EXCL; > + flags = IOMAP_DIO_FORCE_WAIT; > + } > + > + ret = xfs_ilock_iocb(iocb, iolock); > + if (ret) > + return ret; > > /* > * We can't properly handle unaligned direct I/O to reflink files yet, > @@ -590,19 +617,27 @@ xfs_file_dio_write_unaligned( > goto out_unlock; > > /* > - * If we are doing unaligned I/O, we can't allow any other overlapping > - * I/O in-flight at the same time or we risk data corruption. Wait for > - * all other I/O to drain before we submit. > + * If we are doing exclusive unaligned IO, we can't allow any other > + * overlapping IO in-flight at the same time or we risk data corruption. > + * Wait for all other IO to drain before we submit. > */ > - inode_dio_wait(VFS_I(ip)); > + if (!(flags & IOMAP_DIO_UNALIGNED)) > + inode_dio_wait(VFS_I(ip)); Er... this really confused me when I read it -- my first thought was "How can we be in the unaligned direct write function but DIO_UNALIGNED isn't set? Wouldn't we be in some other function if we're doing an aligned direct write?" Then I looked upthread to where Christph said he'd renamed it IOMAP_DIO_SUBBLOCK, but I didn't think that was sufficiently better: if (!(flags & IOMAP_DIO_SUBBLOCK)) iomap_dio_wait(...); This flag doesn't have a 1:1 relationship with the iocb asking for an (fsblock-)unaligned write or the iocb saying that the write involves sub-block io -- this flag really means "I require a stable written mapping, no post-processing (of the disk block) allowed". Admittedly the comment above the definition of IOMAP_DIO_UNALIGNED actually says this, but as we all know I sometimes like to review patchsets backwards. :P How about... IOMAP_DIO_REQUIRE_OVERWRITE ? IOMAP_DIO_REQUIRE_STABLE ? --D > > - /* > - * This must be the only I/O in-flight. Wait on it before we release the > - * iolock to prevent subsequent overlapping I/O. > - */ > trace_xfs_file_direct_write(iocb, from); > ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops, > - &xfs_dio_write_ops, IOMAP_DIO_FORCE_WAIT); > + &xfs_dio_write_ops, flags); > + /* > + * Retry unaligned IO with exclusive blocking semantics if the DIO > + * layer rejected it for mapping or locking reasons. If we are doing > + * nonblocking user IO, propagate the error. > + */ > + if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) { > + ASSERT(flags & IOMAP_DIO_UNALIGNED); > + xfs_iunlock(ip, iolock); > + goto retry_exclusive; > + } > + > out_unlock: > if (iolock) > xfs_iunlock(ip, iolock); > diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c > index 7b9ff824e82d48..dc8c86e98b99bf 100644 > --- a/fs/xfs/xfs_iomap.c > +++ b/fs/xfs/xfs_iomap.c > @@ -784,15 +784,30 @@ xfs_direct_write_iomap_begin( > goto allocate_blocks; > > /* > - * NOWAIT IO needs to span the entire requested IO with a single map so > - * that we avoid partial IO failures due to the rest of the IO range not > - * covered by this map triggering an EAGAIN condition when it is > - * subsequently mapped and aborting the IO. > + * NOWAIT and unaligned IO needs to span the entire requested IO with a > + * single map so that we avoid partial IO failures due to the rest of > + * the IO range not covered by this map triggering an EAGAIN condition > + * when it is subsequently mapped and aborting the IO. > */ > - if ((flags & IOMAP_NOWAIT) && > - !imap_spans_range(&imap, offset_fsb, end_fsb)) { > + if (flags & (IOMAP_NOWAIT | IOMAP_UNALIGNED)) { > error = -EAGAIN; > - goto out_unlock; > + if (!imap_spans_range(&imap, offset_fsb, end_fsb)) > + goto out_unlock; > + } > + > + /* > + * For unsigned I/O we can't convert an unwritten extents if the I/O is > + * not block size aligned, as such a conversion would have to do > + * sub-block zeroing, and that can only be done under an exclusive > + * IOLOCK. Hence if this is not a written extent, return EAGAIN to tell > + * the caller to try again. > + */ > + if (flags & IOMAP_UNALIGNED) { > + error = -EAGAIN; > + if (imap.br_state != XFS_EXT_NORM && > + ((offset & mp->m_blockmask) || > + ((offset + length) & mp->m_blockmask))) > + goto out_unlock; > } > > xfs_iunlock(ip, lockmode); > @@ -801,7 +816,7 @@ xfs_direct_write_iomap_begin( > > allocate_blocks: > error = -EAGAIN; > - if (flags & IOMAP_NOWAIT) > + if (flags & (IOMAP_NOWAIT | IOMAP_UNALIGNED)) > goto out_unlock; > > /* > -- > 2.29.2 >
[another full quote removed, guys please send properly formatted email] On Wed, Jan 20, 2021 at 10:40:56AM -0800, Darrick J. Wong wrote: > > + if (!(flags & IOMAP_DIO_UNALIGNED)) > > + inode_dio_wait(VFS_I(ip)); > > Er... this really confused me when I read it -- my first thought was > "How can we be in the unaligned direct write function but DIO_UNALIGNED > isn't set? Wouldn't we be in some other function if we're doing an > aligned direct write?" > > Then I looked upthread to where Christph said he'd renamed it > IOMAP_DIO_SUBBLOCK, but I didn't think that was sufficiently better: > > if (!(flags & IOMAP_DIO_SUBBLOCK)) > iomap_dio_wait(...); > > This flag doesn't have a 1:1 relationship with the iocb asking for an > (fsblock-)unaligned write or the iocb saying that the write involves > sub-block io -- this flag really means "I require a stable written > mapping, no post-processing (of the disk block) allowed". Would: if (flags & IOMAP_DIO_FORCE_WAIT) inode_dio_wait(VFS_I(ip)); look any better to you? Behavior would be the same.
On Wed, Jan 20, 2021 at 07:44:00PM +0100, Christoph Hellwig wrote: > [another full quote removed, guys please send properly formatted email] > > On Wed, Jan 20, 2021 at 10:40:56AM -0800, Darrick J. Wong wrote: > > > + if (!(flags & IOMAP_DIO_UNALIGNED)) > > > + inode_dio_wait(VFS_I(ip)); > > > > Er... this really confused me when I read it -- my first thought was > > "How can we be in the unaligned direct write function but DIO_UNALIGNED > > isn't set? Wouldn't we be in some other function if we're doing an > > aligned direct write?" > > > > Then I looked upthread to where Christph said he'd renamed it > > IOMAP_DIO_SUBBLOCK, but I didn't think that was sufficiently better: > > > > if (!(flags & IOMAP_DIO_SUBBLOCK)) > > iomap_dio_wait(...); > > > > This flag doesn't have a 1:1 relationship with the iocb asking for an > > (fsblock-)unaligned write or the iocb saying that the write involves > > sub-block io -- this flag really means "I require a stable written > > mapping, no post-processing (of the disk block) allowed". > > Would: > > if (flags & IOMAP_DIO_FORCE_WAIT) > inode_dio_wait(VFS_I(ip)); > > look any better to you? Behavior would be the same. Looks fine to me. --D
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index b181db42f2f32f..4e475e750148db 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -544,22 +544,35 @@ xfs_file_dio_write_aligned( /* * Handle block unaligned direct IO writes * - * In most cases direct IO writes will be done holding IOLOCK_SHARED, allowing - * them to be done in parallel with reads and other direct IO writes. However, - * if the I/O is not aligned to filesystem blocks, the direct I/O layer may - * need to do sub-block zeroing and that requires serialisation against other - * direct I/Os to the same block. In this case we need to serialise the - * submission of the unaligned I/Os so that we don't get racing block zeroing in - * the dio layer. + * In most cases direct IO writes will be done holding IOLOCK_SHARED + * allowing them to be done in parallel with reads and other direct IO writes. + * However, if the IO is not aligned to filesystem blocks, the direct IO layer + * may need to do sub-block zeroing and that requires serialisation against other + * direct IOs to the same block. In the case where sub-block zeroing is not + * required, we can do concurrent sub-block dios to the same block successfully. * - * To provide the same serialisation for AIO, we also need to wait for + * Hence we have two cases here - the shared, optimisitic fast path for written + * extents, and everything else that needs exclusive IO path access across the + * entire IO. + * + * For the first case, we do all the checks we need at the mapping layer in the + * DIO code as part of the existing NOWAIT infrastructure. Hence all we need to + * do to support concurrent subblock dio is first try a non-blocking submission. + * If that returns -EAGAIN, then we simply repeat the IO submission with full + * IO exclusivity guaranteed so that we avoid racing sub-block zeroing. + * + * The only wrinkle in this case is that the iomap DIO code always does + * partial tail sub-block zeroing for post-EOF writes. Hence for any IO that + * _ends_ past the current EOF we need to run with full exclusivity. Note that + * we also check for the start of IO being beyond EOF because then zeroing + * between the old EOF and the start of the IO is required and that also + * requires exclusivity. Hence we avoid lock cycles and blocking under + * IOCB_NOWAIT for this situation, too. + * + * To provide the exclusivity required when using AIO, we also need to wait for * outstanding IOs to complete so that unwritten extent conversion is completed * before we try to map the overlapping block. This is currently implemented by * hitting it with a big hammer (i.e. inode_dio_wait()). - * - * This means that unaligned dio writes always block. There is no "nowait" fast - * path in this code - if IOCB_NOWAIT is set we simply return -EAGAIN up front - * and we don't have to worry about that anymore. */ static noinline ssize_t xfs_file_dio_write_unaligned( @@ -567,13 +580,27 @@ xfs_file_dio_write_unaligned( struct kiocb *iocb, struct iov_iter *from) { - int iolock = XFS_IOLOCK_EXCL; + size_t isize = i_size_read(VFS_I(ip)); + size_t count = iov_iter_count(from); + int iolock = XFS_IOLOCK_SHARED; + unsigned int flags = IOMAP_DIO_UNALIGNED; ssize_t ret; - /* unaligned dio always waits, bail */ - if (iocb->ki_flags & IOCB_NOWAIT) - return -EAGAIN; - xfs_ilock(ip, iolock); + /* + * Extending writes need exclusivity because of the sub-block zeroing + * that the DIO code always does for partial tail blocks beyond EOF. + */ + if (iocb->ki_pos > isize || iocb->ki_pos + count >= isize) { +retry_exclusive: + if (iocb->ki_flags & IOCB_NOWAIT) + return -EAGAIN; + iolock = XFS_IOLOCK_EXCL; + flags = IOMAP_DIO_FORCE_WAIT; + } + + ret = xfs_ilock_iocb(iocb, iolock); + if (ret) + return ret; /* * We can't properly handle unaligned direct I/O to reflink files yet, @@ -590,19 +617,27 @@ xfs_file_dio_write_unaligned( goto out_unlock; /* - * If we are doing unaligned I/O, we can't allow any other overlapping - * I/O in-flight at the same time or we risk data corruption. Wait for - * all other I/O to drain before we submit. + * If we are doing exclusive unaligned IO, we can't allow any other + * overlapping IO in-flight at the same time or we risk data corruption. + * Wait for all other IO to drain before we submit. */ - inode_dio_wait(VFS_I(ip)); + if (!(flags & IOMAP_DIO_UNALIGNED)) + inode_dio_wait(VFS_I(ip)); - /* - * This must be the only I/O in-flight. Wait on it before we release the - * iolock to prevent subsequent overlapping I/O. - */ trace_xfs_file_direct_write(iocb, from); ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops, - &xfs_dio_write_ops, IOMAP_DIO_FORCE_WAIT); + &xfs_dio_write_ops, flags); + /* + * Retry unaligned IO with exclusive blocking semantics if the DIO + * layer rejected it for mapping or locking reasons. If we are doing + * nonblocking user IO, propagate the error. + */ + if (ret == -EAGAIN && !(iocb->ki_flags & IOCB_NOWAIT)) { + ASSERT(flags & IOMAP_DIO_UNALIGNED); + xfs_iunlock(ip, iolock); + goto retry_exclusive; + } + out_unlock: if (iolock) xfs_iunlock(ip, iolock); diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 7b9ff824e82d48..dc8c86e98b99bf 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -784,15 +784,30 @@ xfs_direct_write_iomap_begin( goto allocate_blocks; /* - * NOWAIT IO needs to span the entire requested IO with a single map so - * that we avoid partial IO failures due to the rest of the IO range not - * covered by this map triggering an EAGAIN condition when it is - * subsequently mapped and aborting the IO. + * NOWAIT and unaligned IO needs to span the entire requested IO with a + * single map so that we avoid partial IO failures due to the rest of + * the IO range not covered by this map triggering an EAGAIN condition + * when it is subsequently mapped and aborting the IO. */ - if ((flags & IOMAP_NOWAIT) && - !imap_spans_range(&imap, offset_fsb, end_fsb)) { + if (flags & (IOMAP_NOWAIT | IOMAP_UNALIGNED)) { error = -EAGAIN; - goto out_unlock; + if (!imap_spans_range(&imap, offset_fsb, end_fsb)) + goto out_unlock; + } + + /* + * For unsigned I/O we can't convert an unwritten extents if the I/O is + * not block size aligned, as such a conversion would have to do + * sub-block zeroing, and that can only be done under an exclusive + * IOLOCK. Hence if this is not a written extent, return EAGAIN to tell + * the caller to try again. + */ + if (flags & IOMAP_UNALIGNED) { + error = -EAGAIN; + if (imap.br_state != XFS_EXT_NORM && + ((offset & mp->m_blockmask) || + ((offset + length) & mp->m_blockmask))) + goto out_unlock; } xfs_iunlock(ip, lockmode); @@ -801,7 +816,7 @@ xfs_direct_write_iomap_begin( allocate_blocks: error = -EAGAIN; - if (flags & IOMAP_NOWAIT) + if (flags & (IOMAP_NOWAIT | IOMAP_UNALIGNED)) goto out_unlock; /*