Straight switch over to using iomap for direct I/O - we already have the
non-COW dio path in write_begin for DAX and files with extent size hints,
so nothing to add there. The COW path is ported over from the old
get_blocks version and a bit of a mess, but I have some work in progress
to make it look more like the buffered I/O COW path.
This gets rid of xfs_get_blocks_direct and the last caller of
xfs_get_blocks with the create flag set, so all that code can be removed.
Last but not least I've removed a comment in xfs_filemap_fault that
refers to xfs_get_blocks entirely instead of updating it - while the
reference is correct, the whole DAX fault path looks different than
the non-DAX one, so it seems rather pointless.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/iomap.c | 2 +-
fs/xfs/xfs_aops.c | 291 ++---------------------------------------------------
fs/xfs/xfs_aops.h | 6 --
fs/xfs/xfs_file.c | 149 +++++++++++----------------
fs/xfs/xfs_iomap.c | 50 +++++++--
5 files changed, 111 insertions(+), 387 deletions(-)
diff --git a/fs/iomap.c b/fs/iomap.c
index 93d36fd..fc24462 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -591,7 +591,7 @@ EXPORT_SYMBOL_GPL(iomap_fiemap);
* iomap.h:
*/
#define IOMAP_DIO_WRITE (1 << 30)
-#define IOMAP_DIO_DIRTY (1 << 31)
+#define IOMAP_DIO_DIRTY (1 << 31)
struct iomap_dio {
struct kiocb *iocb;
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index e8f6c2b..265000a 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -37,11 +37,6 @@
#include <linux/pagevec.h>
#include <linux/writeback.h>
-/* flags for direct write completions */
-#define XFS_DIO_FLAG_UNWRITTEN (1 << 0)
-#define XFS_DIO_FLAG_APPEND (1 << 1)
-#define XFS_DIO_FLAG_COW (1 << 2)
-
/*
* structure owned by writepages passed to individual writepage calls
*/
@@ -1176,45 +1171,6 @@ xfs_vm_releasepage(
}
/*
- * When we map a DIO buffer, we may need to pass flags to
- * xfs_end_io_direct_write to tell it what kind of write IO we are doing.
- *
- * Note that for DIO, an IO to the highest supported file block offset (i.e.
- * 2^63 - 1FSB bytes) will result in the offset + count overflowing a signed 64
- * bit variable. Hence if we see this overflow, we have to assume that the IO is
- * extending the file size. We won't know for sure until IO completion is run
- * and the actual max write offset is communicated to the IO completion
- * routine.
- */
-static void
-xfs_map_direct(
- struct inode *inode,
- struct buffer_head *bh_result,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset,
- bool is_cow)
-{
- uintptr_t *flags = (uintptr_t *)&bh_result->b_private;
- xfs_off_t size = bh_result->b_size;
-
- trace_xfs_get_blocks_map_direct(XFS_I(inode), offset, size,
- ISUNWRITTEN(imap) ? XFS_IO_UNWRITTEN : is_cow ? XFS_IO_COW :
- XFS_IO_OVERWRITE, imap);
-
- if (ISUNWRITTEN(imap)) {
- *flags |= XFS_DIO_FLAG_UNWRITTEN;
- set_buffer_defer_completion(bh_result);
- } else if (is_cow) {
- *flags |= XFS_DIO_FLAG_COW;
- set_buffer_defer_completion(bh_result);
- }
- if (offset + size > i_size_read(inode) || offset + size < 0) {
- *flags |= XFS_DIO_FLAG_APPEND;
- set_buffer_defer_completion(bh_result);
- }
-}
-
-/*
* If this is O_DIRECT or the mpage code calling tell them how large the mapping
* is, so that we can avoid repeated get_blocks calls.
*
@@ -1254,51 +1210,12 @@ xfs_map_trim_size(
bh_result->b_size = mapping_size;
}
-/* Bounce unaligned directio writes to the page cache. */
static int
-xfs_bounce_unaligned_dio_write(
- struct xfs_inode *ip,
- xfs_fileoff_t offset_fsb,
- struct xfs_bmbt_irec *imap)
-{
- struct xfs_bmbt_irec irec;
- xfs_fileoff_t delta;
- bool shared;
- bool x;
- int error;
-
- irec = *imap;
- if (offset_fsb > irec.br_startoff) {
- delta = offset_fsb - irec.br_startoff;
- irec.br_blockcount -= delta;
- irec.br_startblock += delta;
- irec.br_startoff = offset_fsb;
- }
- error = xfs_reflink_trim_around_shared(ip, &irec, &shared, &x);
- if (error)
- return error;
-
- /*
- * We're here because we're trying to do a directio write to a
- * region that isn't aligned to a filesystem block. If any part
- * of the extent is shared, fall back to buffered mode to handle
- * the RMW. This is done by returning -EREMCHG ("remote addr
- * changed"), which is caught further up the call stack.
- */
- if (shared) {
- trace_xfs_reflink_bounce_dio_write(ip, imap);
- return -EREMCHG;
- }
- return 0;
-}
-
-STATIC int
-__xfs_get_blocks(
+xfs_get_blocks(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
- int create,
- bool direct)
+ int create)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
@@ -1309,10 +1226,8 @@ __xfs_get_blocks(
int nimaps = 1;
xfs_off_t offset;
ssize_t size;
- int new = 0;
- bool is_cow = false;
- BUG_ON(create && !direct);
+ BUG_ON(create);
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
@@ -1321,7 +1236,7 @@ __xfs_get_blocks(
ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
size = bh_result->b_size;
- if (!create && offset >= i_size_read(inode))
+ if (offset >= i_size_read(inode))
return 0;
/*
@@ -1336,73 +1251,12 @@ __xfs_get_blocks(
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
- if (create && direct && xfs_is_reflink_inode(ip)) {
- is_cow = xfs_reflink_find_cow_mapping(ip, offset, &imap);
- ASSERT(!is_cow || !isnullstartblock(imap.br_startblock));
- }
-
- if (!is_cow) {
- error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
- &imap, &nimaps, XFS_BMAPI_ENTIRE);
- /*
- * Truncate an overwrite extent if there's a pending CoW
- * reservation before the end of this extent. This
- * forces us to come back to get_blocks to take care of
- * the CoW.
- */
- if (create && direct && nimaps &&
- imap.br_startblock != HOLESTARTBLOCK &&
- imap.br_startblock != DELAYSTARTBLOCK &&
- !ISUNWRITTEN(&imap))
- xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb,
- &imap);
- }
+ error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
+ &imap, &nimaps, XFS_BMAPI_ENTIRE);
if (error)
goto out_unlock;
- /*
- * The only time we can ever safely find delalloc blocks on direct I/O
- * is a dio write to post-eof speculative preallocation. All other
- * scenarios are indicative of a problem or misuse (such as mixing
- * direct and mapped I/O).
- *
- * The file may be unmapped by the time we get here so we cannot
- * reliably fail the I/O based on mapping. Instead, fail the I/O if this
- * is a read or a write within eof. Otherwise, carry on but warn as a
- * precuation if the file happens to be mapped.
- */
- if (direct && imap.br_startblock == DELAYSTARTBLOCK) {
- if (!create || offset < i_size_read(VFS_I(ip))) {
- WARN_ON_ONCE(1);
- error = -EIO;
- goto out_unlock;
- }
- WARN_ON_ONCE(mapping_mapped(VFS_I(ip)->i_mapping));
- }
-
- /* for DAX, we convert unwritten extents directly */
- if (create &&
- (!nimaps ||
- (imap.br_startblock == HOLESTARTBLOCK ||
- imap.br_startblock == DELAYSTARTBLOCK) ||
- (IS_DAX(inode) && ISUNWRITTEN(&imap)))) {
- /*
- * xfs_iomap_write_direct() expects the shared lock. It
- * is unlocked on return.
- */
- if (lockmode == XFS_ILOCK_EXCL)
- xfs_ilock_demote(ip, lockmode);
-
- error = xfs_iomap_write_direct(ip, offset, size,
- &imap, nimaps);
- if (error)
- return error;
- new = 1;
-
- trace_xfs_get_blocks_alloc(ip, offset, size,
- ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN
- : XFS_IO_DELALLOC, &imap);
- } else if (nimaps) {
+ if (nimaps) {
trace_xfs_get_blocks_found(ip, offset, size,
ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN
: XFS_IO_OVERWRITE, &imap);
@@ -1412,12 +1266,6 @@ __xfs_get_blocks(
goto out_unlock;
}
- if (IS_DAX(inode) && create) {
- ASSERT(!ISUNWRITTEN(&imap));
- /* zeroing is not needed at a higher layer */
- new = 0;
- }
-
/* trim mapping down to size requested */
xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size);
@@ -1427,43 +1275,14 @@ __xfs_get_blocks(
*/
if (imap.br_startblock != HOLESTARTBLOCK &&
imap.br_startblock != DELAYSTARTBLOCK &&
- (create || !ISUNWRITTEN(&imap))) {
- if (create && direct && !is_cow) {
- error = xfs_bounce_unaligned_dio_write(ip, offset_fsb,
- &imap);
- if (error)
- return error;
- }
-
+ !ISUNWRITTEN(&imap))
xfs_map_buffer(inode, bh_result, &imap, offset);
- if (ISUNWRITTEN(&imap))
- set_buffer_unwritten(bh_result);
- /* direct IO needs special help */
- if (create)
- xfs_map_direct(inode, bh_result, &imap, offset, is_cow);
- }
/*
* If this is a realtime file, data may be on a different device.
* to that pointed to from the buffer_head b_bdev currently.
*/
bh_result->b_bdev = xfs_find_bdev_for_inode(inode);
-
- /*
- * If we previously allocated a block out beyond eof and we are now
- * coming back to use it then we will need to flag it as new even if it
- * has a disk address.
- *
- * With sub-block writes into unwritten extents we also need to mark
- * the buffer as new so that the unwritten parts of the buffer gets
- * correctly zeroed.
- */
- if (create &&
- ((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
- (offset >= i_size_read(inode)) ||
- (new || ISUNWRITTEN(&imap))))
- set_buffer_new(bh_result);
-
return 0;
out_unlock:
@@ -1471,100 +1290,6 @@ __xfs_get_blocks(
return error;
}
-int
-xfs_get_blocks(
- struct inode *inode,
- sector_t iblock,
- struct buffer_head *bh_result,
- int create)
-{
- return __xfs_get_blocks(inode, iblock, bh_result, create, false);
-}
-
-int
-xfs_get_blocks_direct(
- struct inode *inode,
- sector_t iblock,
- struct buffer_head *bh_result,
- int create)
-{
- return __xfs_get_blocks(inode, iblock, bh_result, create, true);
-}
-
-/*
- * Complete a direct I/O write request.
- *
- * xfs_map_direct passes us some flags in the private data to tell us what to
- * do. If no flags are set, then the write IO is an overwrite wholly within
- * the existing allocated file size and so there is nothing for us to do.
- *
- * Note that in this case the completion can be called in interrupt context,
- * whereas if we have flags set we will always be called in task context
- * (i.e. from a workqueue).
- */
-int
-xfs_end_io_direct_write(
- struct kiocb *iocb,
- loff_t offset,
- ssize_t size,
- void *private)
-{
- struct inode *inode = file_inode(iocb->ki_filp);
- struct xfs_inode *ip = XFS_I(inode);
- uintptr_t flags = (uintptr_t)private;
- int error = 0;
-
- trace_xfs_end_io_direct_write(ip, offset, size);
-
- if (XFS_FORCED_SHUTDOWN(ip->i_mount))
- return -EIO;
-
- if (size <= 0)
- return size;
-
- /*
- * The flags tell us whether we are doing unwritten extent conversions
- * or an append transaction that updates the on-disk file size. These
- * cases are the only cases where we should *potentially* be needing
- * to update the VFS inode size.
- */
- if (flags == 0) {
- ASSERT(offset + size <= i_size_read(inode));
- return 0;
- }
-
- /*
- * We need to update the in-core inode size here so that we don't end up
- * with the on-disk inode size being outside the in-core inode size. We
- * have no other method of updating EOF for AIO, so always do it here
- * if necessary.
- *
- * We need to lock the test/set EOF update as we can be racing with
- * other IO completions here to update the EOF. Failing to serialise
- * here can result in EOF moving backwards and Bad Things Happen when
- * that occurs.
- */
- spin_lock(&ip->i_flags_lock);
- if (offset + size > i_size_read(inode))
- i_size_write(inode, offset + size);
- spin_unlock(&ip->i_flags_lock);
-
- if (flags & XFS_DIO_FLAG_COW)
- error = xfs_reflink_end_cow(ip, offset, size);
- if (flags & XFS_DIO_FLAG_UNWRITTEN) {
- trace_xfs_end_io_direct_write_unwritten(ip, offset, size);
-
- error = xfs_iomap_write_unwritten(ip, offset, size);
- }
- if (flags & XFS_DIO_FLAG_APPEND) {
- trace_xfs_end_io_direct_write_append(ip, offset, size);
-
- error = xfs_setfilesize(ip, offset, size);
- }
-
- return error;
-}
-
STATIC ssize_t
xfs_vm_direct_IO(
struct kiocb *iocb,
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index 34dc00d..cc174ec 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -55,12 +55,6 @@ struct xfs_ioend {
extern const struct address_space_operations xfs_address_space_operations;
-int xfs_get_blocks(struct inode *inode, sector_t offset,
- struct buffer_head *map_bh, int create);
-int xfs_get_blocks_direct(struct inode *inode, sector_t offset,
- struct buffer_head *map_bh, int create);
-int xfs_end_io_direct_write(struct kiocb *iocb, loff_t offset,
- ssize_t size, void *private);
int xfs_setfilesize(struct xfs_inode *ip, xfs_off_t offset, size_t size);
extern void xfs_count_page_state(struct page *, int *, int *);
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index d054b73..f5effa6 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -210,62 +210,21 @@ xfs_file_dio_aio_read(
struct kiocb *iocb,
struct iov_iter *to)
{
- struct address_space *mapping = iocb->ki_filp->f_mapping;
- struct inode *inode = mapping->host;
- struct xfs_inode *ip = XFS_I(inode);
- loff_t isize = i_size_read(inode);
+ struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
size_t count = iov_iter_count(to);
- loff_t end = iocb->ki_pos + count - 1;
- struct iov_iter data;
- struct xfs_buftarg *target;
- ssize_t ret = 0;
+ ssize_t ret;
trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
if (!count)
return 0; /* skip atime */
- if (XFS_IS_REALTIME_INODE(ip))
- target = ip->i_mount->m_rtdev_targp;
- else
- target = ip->i_mount->m_ddev_targp;
-
- /* DIO must be aligned to device logical sector size */
- if ((iocb->ki_pos | count) & target->bt_logical_sectormask) {
- if (iocb->ki_pos == isize)
- return 0;
- return -EINVAL;
- }
-
file_accessed(iocb->ki_filp);
xfs_ilock(ip, XFS_IOLOCK_SHARED);
- if (mapping->nrpages) {
- ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);
- if (ret)
- goto out_unlock;
-
- /*
- * Invalidate whole pages. This can return an error if we fail
- * to invalidate a page, but this should never happen on XFS.
- * Warn if it does fail.
- */
- ret = invalidate_inode_pages2_range(mapping,
- iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
- WARN_ON_ONCE(ret);
- ret = 0;
- }
-
- data = *to;
- ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data,
- xfs_get_blocks_direct, NULL, NULL, 0);
- if (ret >= 0) {
- iocb->ki_pos += ret;
- iov_iter_advance(to, ret);
- }
-
-out_unlock:
+ ret = iomap_dio_rw(iocb, to, &xfs_iomap_ops, NULL);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
+
return ret;
}
@@ -465,6 +424,58 @@ xfs_file_aio_write_checks(
return 0;
}
+static int
+xfs_dio_write_end_io(
+ struct kiocb *iocb,
+ ssize_t size,
+ unsigned flags)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct xfs_inode *ip = XFS_I(inode);
+ loff_t offset = iocb->ki_pos;
+ bool update_size = false;
+ int error = 0;
+
+ trace_xfs_end_io_direct_write(ip, offset, size);
+
+ if (XFS_FORCED_SHUTDOWN(ip->i_mount))
+ return -EIO;
+
+ if (size <= 0)
+ return size;
+
+ /*
+ * We need to update the in-core inode size here so that we don't end up
+ * with the on-disk inode size being outside the in-core inode size. We
+ * have no other method of updating EOF for AIO, so always do it here
+ * if necessary.
+ *
+ * We need to lock the test/set EOF update as we can be racing with
+ * other IO completions here to update the EOF. Failing to serialise
+ * here can result in EOF moving backwards and Bad Things Happen when
+ * that occurs.
+ */
+ spin_lock(&ip->i_flags_lock);
+ if (offset + size > i_size_read(inode)) {
+ i_size_write(inode, offset + size);
+ update_size = true;
+ }
+ spin_unlock(&ip->i_flags_lock);
+
+ if (flags & IOMAP_DIO_COW) {
+ error = xfs_reflink_end_cow(ip, offset, size);
+ if (error)
+ return error;
+ }
+
+ if (flags & IOMAP_DIO_UNWRITTEN)
+ error = xfs_iomap_write_unwritten(ip, offset, size);
+ else if (update_size)
+ error = xfs_setfilesize(ip, offset, size);
+
+ return error;
+}
+
/*
* xfs_file_dio_aio_write - handle direct IO writes
*
@@ -504,9 +515,7 @@ xfs_file_dio_aio_write(
int unaligned_io = 0;
int iolock;
size_t count = iov_iter_count(from);
- loff_t end;
- struct iov_iter data;
- struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
+ struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;
/* DIO must be aligned to device logical sector size */
@@ -534,23 +543,6 @@ xfs_file_dio_aio_write(
if (ret)
goto out;
count = iov_iter_count(from);
- end = iocb->ki_pos + count - 1;
-
- if (mapping->nrpages) {
- ret = filemap_write_and_wait_range(mapping, iocb->ki_pos, end);
- if (ret)
- goto out;
-
- /*
- * Invalidate whole pages. This can return an error if we fail
- * to invalidate a page, but this should never happen on XFS.
- * Warn if it does fail.
- */
- ret = invalidate_inode_pages2_range(mapping,
- iocb->ki_pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
- WARN_ON_ONCE(ret);
- ret = 0;
- }
/*
* If we are doing unaligned IO, wait for all other IO to drain,
@@ -573,22 +565,7 @@ xfs_file_dio_aio_write(
goto out;
}
- data = *from;
- ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data,
- xfs_get_blocks_direct, xfs_end_io_direct_write,
- NULL, DIO_ASYNC_EXTEND);
-
- /* see generic_file_direct_write() for why this is necessary */
- if (mapping->nrpages) {
- invalidate_inode_pages2_range(mapping,
- iocb->ki_pos >> PAGE_SHIFT,
- end >> PAGE_SHIFT);
- }
-
- if (ret > 0) {
- iocb->ki_pos += ret;
- iov_iter_advance(from, ret);
- }
+ ret = iomap_dio_rw(iocb, from, &xfs_iomap_ops, xfs_dio_write_end_io);
out:
xfs_iunlock(ip, iolock);
@@ -1468,15 +1445,9 @@ xfs_filemap_fault(
return xfs_filemap_page_mkwrite(vma, vmf);
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
- if (IS_DAX(inode)) {
- /*
- * we do not want to trigger unwritten extent conversion on read
- * faults - that is unnecessary overhead and would also require
- * changes to xfs_get_blocks_direct() to map unwritten extent
- * ioend for conversion on read-only mappings.
- */
+ if (IS_DAX(inode))
ret = dax_iomap_fault(vma, vmf, &xfs_iomap_ops);
- } else
+ else
ret = filemap_fault(vma, vmf);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 15a83813..0d14742 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -950,6 +950,19 @@ static inline bool imap_needs_alloc(struct inode *inode,
(IS_DAX(inode) && ISUNWRITTEN(imap));
}
+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.
+ */
+ if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO)))
+ return true;
+ if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE))
+ return true;
+ return false;
+}
+
static int
xfs_file_iomap_begin(
struct inode *inode,
@@ -969,18 +982,14 @@ xfs_file_iomap_begin(
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
- if ((flags & IOMAP_WRITE) && !IS_DAX(inode) &&
- !xfs_get_extsz_hint(ip)) {
+ if (((flags & (IOMAP_WRITE | IOMAP_DIRECT)) == IOMAP_WRITE) &&
+ !IS_DAX(inode) && !xfs_get_extsz_hint(ip)) {
/* Reserve delalloc blocks for regular writeback. */
return xfs_file_iomap_begin_delay(inode, offset, length, flags,
iomap);
}
- /*
- * COW writes will allocate delalloc space, so we need to make sure
- * to take the lock exclusively here.
- */
- if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+ if (need_excl_ilock(ip, flags)) {
lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, XFS_ILOCK_EXCL);
} else {
@@ -993,17 +1002,41 @@ xfs_file_iomap_begin(
offset_fsb = XFS_B_TO_FSBT(mp, offset);
end_fsb = XFS_B_TO_FSB(mp, offset + length);
+ if (xfs_is_reflink_inode(ip) &&
+ (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT)) {
+ shared = xfs_reflink_find_cow_mapping(ip, offset, &imap);
+ if (shared) {
+ xfs_iunlock(ip, lockmode);
+ goto alloc_done;
+ }
+ ASSERT(!isnullstartblock(imap.br_startblock));
+ }
+
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (error)
goto out_unlock;
- if (flags & IOMAP_REPORT) {
+ if ((flags & IOMAP_REPORT) ||
+ (xfs_is_reflink_inode(ip) &&
+ (flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))) {
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
&trimmed);
if (error)
goto out_unlock;
+
+ /*
+ * We're here because we're trying to do a directio write to a
+ * region that isn't aligned to a filesystem block. If the
+ * extent is shared, fall back to buffered mode to handle the
+ * RMW.
+ */
+ if (!(flags & IOMAP_REPORT) && shared) {
+ trace_xfs_reflink_bounce_dio_write(ip, &imap);
+ error = -EREMCHG;
+ goto out_unlock;
+ }
}
if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
@@ -1038,6 +1071,7 @@ xfs_file_iomap_begin(
if (error)
return error;
+alloc_done:
iomap->flags = IOMAP_F_NEW;
trace_xfs_iomap_alloc(ip, offset, length, 0, &imap);
} else {
--
2.1.4
--
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