[PATCH v3 09/10] fs/xfs: Handle CoW for fsdax write() path

Shiyang Ruan
2021-03-19T01:54:33Z

In fsdax mode, WRITE and ZERO on a shared extent need CoW performed. After
CoW, new allocated extents needs to be remapped to the file. So, add an
iomap_end for dax write ops to do the remapping work.

Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
---
fs/xfs/xfs_bmap_util.c | 3 +--
fs/xfs/xfs_file.c | 9 +++----
fs/xfs/xfs_iomap.c | 58 +++++++++++++++++++++++++++++++++++++++++-
fs/xfs/xfs_iomap.h | 4 +++
fs/xfs/xfs_iops.c | 7 +++--
fs/xfs/xfs_reflink.c | 3 +--
6 files changed, 69 insertions(+), 15 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 7371a7f7c652..809013de9915 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -976,8 +976,7 @@ xfs_free_file_space(
return 0;
if (offset + len > XFS_ISIZE(ip))
len = XFS_ISIZE(ip) - offset;
- error = iomap_zero_range(VFS_I(ip), offset, len, NULL,
- &xfs_buffered_write_iomap_ops);
+ error = xfs_iomap_zero_range(VFS_I(ip), offset, len, NULL);
if (error)
return error;

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5b0f93f73837..1987d15eab61 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -623,11 +623,8 @@ xfs_file_dax_write(
count = iov_iter_count(from);

trace_xfs_file_dax_write(ip, count, pos);
- ret = dax_iomap_rw(iocb, from, &xfs_direct_write_iomap_ops);
- if (ret > 0 && iocb->ki_pos > i_size_read(inode)) {
- i_size_write(inode, iocb->ki_pos);
- error = xfs_setfilesize(ip, pos, ret);
- }
+ ret = dax_iomap_rw(iocb, from, &xfs_dax_write_iomap_ops);
+
out:
xfs_iunlock(ip, iolock);
if (error)
@@ -1250,7 +1247,7 @@ __xfs_filemap_fault(

ret = dax_iomap_fault(vmf, pe_size, &pfn, NULL,
(write_fault && !vmf->cow_page) ?
- &xfs_direct_write_iomap_ops :
+ &xfs_dax_write_iomap_ops :
&xfs_read_iomap_ops);
if (ret & VM_FAULT_NEEDDSYNC)
ret = dax_finish_sync_fault(vmf, pe_size, pfn);
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 7b9ff824e82d..0afae5dbbce1 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -771,7 +771,8 @@ xfs_direct_write_iomap_begin(

/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &cmap, &shared,
- &lockmode, flags & IOMAP_DIRECT);
+ &lockmode,
+ flags & IOMAP_DIRECT || IS_DAX(inode));
if (error)
goto out_unlock;
if (shared)
@@ -850,6 +851,38 @@ const struct iomap_ops xfs_direct_write_iomap_ops = {
.iomap_begin = xfs_direct_write_iomap_begin,
};

+static int
+xfs_dax_write_iomap_end(
+ struct inode *inode,
+ loff_t pos,
+ loff_t length,
+ ssize_t written,
+ unsigned int flags,
+ struct iomap *iomap)
+{
+ int error = 0;
+ xfs_inode_t *ip = XFS_I(inode);
+ bool cow = xfs_is_cow_inode(ip);
+
+ if (pos + written > i_size_read(inode)) {
+ i_size_write(inode, pos + written);
+ error = xfs_setfilesize(ip, pos, written);
+ if (error && cow) {
+ xfs_reflink_cancel_cow_range(ip, pos, written, true);
+ return error;
+ }
+ }
+ if (cow)
+ error = xfs_reflink_end_cow(ip, pos, written);
+
+ return error;
+}
+
+const struct iomap_ops xfs_dax_write_iomap_ops = {
+ .iomap_begin = xfs_direct_write_iomap_begin,
+ .iomap_end = xfs_dax_write_iomap_end,
+};
+
static int
xfs_buffered_write_iomap_begin(
struct inode *inode,
@@ -1308,3 +1341,26 @@ xfs_xattr_iomap_begin(
const struct iomap_ops xfs_xattr_iomap_ops = {
.iomap_begin = xfs_xattr_iomap_begin,
};
+
+int
+xfs_iomap_zero_range(
+ struct inode *inode,
+ loff_t offset,
+ loff_t len,
+ bool *did_zero)
+{
+ return iomap_zero_range(inode, offset, len, did_zero,
+ IS_DAX(inode) ? &xfs_dax_write_iomap_ops :
+ &xfs_buffered_write_iomap_ops);
+}
+
+int
+xfs_iomap_truncate_page(
+ struct inode *inode,
+ loff_t pos,
+ bool *did_zero)
+{
+ return iomap_truncate_page(inode, pos, did_zero,
+ IS_DAX(inode) ? &xfs_dax_write_iomap_ops :
+ &xfs_buffered_write_iomap_ops);
+}
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index 7d3703556d0e..8adb2bf78a5a 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -14,6 +14,9 @@ struct xfs_bmbt_irec;
int xfs_iomap_write_direct(struct xfs_inode *ip, xfs_fileoff_t offset_fsb,
xfs_fileoff_t count_fsb, struct xfs_bmbt_irec *imap);
int xfs_iomap_write_unwritten(struct xfs_inode *, xfs_off_t, xfs_off_t, bool);
+int xfs_iomap_zero_range(struct inode *inode, loff_t offset, loff_t len,
+ bool *did_zero);
+int xfs_iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero);
xfs_fileoff_t xfs_iomap_eof_align_last_fsb(struct xfs_inode *ip,
xfs_fileoff_t end_fsb);

@@ -42,6 +45,7 @@ xfs_aligned_fsb_count(

extern const struct iomap_ops xfs_buffered_write_iomap_ops;
extern const struct iomap_ops xfs_direct_write_iomap_ops;
+extern const struct iomap_ops xfs_dax_write_iomap_ops;
extern const struct iomap_ops xfs_read_iomap_ops;
extern const struct iomap_ops xfs_seek_iomap_ops;
extern const struct iomap_ops xfs_xattr_iomap_ops;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 67c8dc9de8aa..2281161e05c8 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -889,8 +889,8 @@ xfs_setattr_size(
*/
if (newsize > oldsize) {
trace_xfs_zero_eof(ip, oldsize, newsize - oldsize);
- error = iomap_zero_range(inode, oldsize, newsize - oldsize,
- &did_zeroing, &xfs_buffered_write_iomap_ops);
+ error = xfs_iomap_zero_range(inode, oldsize, newsize - oldsize,
+ &did_zeroing);
} else {
/*
* iomap won't detect a dirty page over an unwritten block (or a
@@ -902,8 +902,7 @@ xfs_setattr_size(
newsize);
if (error)
return error;
- error = iomap_truncate_page(inode, newsize, &did_zeroing,
- &xfs_buffered_write_iomap_ops);
+ error = xfs_iomap_truncate_page(inode, newsize, &did_zeroing);
}

if (error)
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index f5b3a3da36b7..73c556c2ff76 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -1245,8 +1245,7 @@ xfs_reflink_zero_posteof(
return 0;

trace_xfs_zero_eof(ip, isize, pos - isize);
- return iomap_zero_range(VFS_I(ip), isize, pos - isize, NULL,
- &xfs_buffered_write_iomap_ops);
+ return xfs_iomap_zero_range(VFS_I(ip), isize, pos - isize, NULL);
}

/*
--
2.30.1