[PATCH 06/12] xfs: remove the fork fields in the writepage_ctx and ioend

Christoph Hellwig
2019-10-15T15:44:17Z

In preparation for moving the writeback code to iomap.c, replace the
XFS-specific COW fork concept with the iomap IOMAP_F_SHARED flag.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_aops.c | 71 ++++++++++++++++++++++++++++++-----------------
fs/xfs/xfs_aops.h | 2 +-
2 files changed, 46 insertions(+), 27 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index df5955388adc..00fe40b35f72 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -23,7 +23,6 @@
*/
struct xfs_writepage_ctx {
struct iomap iomap;
- int fork;
unsigned int data_seq;
unsigned int cow_seq;
struct xfs_ioend *ioend;
@@ -272,7 +271,7 @@ xfs_end_ioend(
*/
error = blk_status_to_errno(ioend->io_bio->bi_status);
if (unlikely(error)) {
- if (ioend->io_fork == XFS_COW_FORK)
+ if (ioend->io_flags & IOMAP_F_SHARED)
xfs_reflink_cancel_cow_range(ip, offset, size, true);
goto done;
}
@@ -280,7 +279,7 @@ xfs_end_ioend(
/*
* Success: commit the COW or unwritten blocks if needed.
*/
- if (ioend->io_fork == XFS_COW_FORK)
+ if (ioend->io_flags & IOMAP_F_SHARED)
error = xfs_reflink_end_cow(ip, offset, size);
else if (ioend->io_type == IOMAP_UNWRITTEN)
error = xfs_iomap_write_unwritten(ip, offset, size, false);
@@ -304,7 +303,8 @@ xfs_ioend_can_merge(
{
if (ioend->io_bio->bi_status != next->io_bio->bi_status)
return false;
- if ((ioend->io_fork == XFS_COW_FORK) ^ (next->io_fork == XFS_COW_FORK))
+ if ((ioend->io_flags & IOMAP_F_SHARED) ^
+ (next->io_flags & IOMAP_F_SHARED))
return false;
if ((ioend->io_type == IOMAP_UNWRITTEN) ^
(next->io_type == IOMAP_UNWRITTEN))
@@ -404,6 +404,13 @@ xfs_end_io(
}
}

+static inline bool xfs_ioend_needs_workqueue(struct xfs_ioend *ioend)
+{
+ return ioend->io_private ||
+ ioend->io_type == IOMAP_UNWRITTEN ||
+ (ioend->io_flags & IOMAP_F_SHARED);
+}
+
STATIC void
xfs_end_bio(
struct bio *bio)
@@ -413,9 +420,7 @@ xfs_end_bio(
struct xfs_mount *mp = ip->i_mount;
unsigned long flags;

- if (ioend->io_fork == XFS_COW_FORK ||
- ioend->io_type == IOMAP_UNWRITTEN ||
- ioend->io_private) {
+ if (xfs_ioend_needs_workqueue(ioend)) {
spin_lock_irqsave(&ip->i_ioend_lock, flags);
if (list_empty(&ip->i_ioend_list))
WARN_ON_ONCE(!queue_work(mp->m_unwritten_workqueue,
@@ -444,7 +449,7 @@ xfs_imap_valid(
* covers the offset. Be careful to check this first because the caller
* can revalidate a COW mapping without updating the data seqno.
*/
- if (wpc->fork == XFS_COW_FORK)
+ if (wpc->iomap.flags & IOMAP_F_SHARED)
return true;

/*
@@ -474,6 +479,7 @@ static int
xfs_convert_blocks(
struct xfs_writepage_ctx *wpc,
struct xfs_inode *ip,
+ int whichfork,
loff_t offset)
{
int error;
@@ -485,8 +491,8 @@ xfs_convert_blocks(
* delalloc extent if free space is sufficiently fragmented.
*/
do {
- error = xfs_bmapi_convert_delalloc(ip, wpc->fork, offset,
- &wpc->iomap, wpc->fork == XFS_COW_FORK ?
+ error = xfs_bmapi_convert_delalloc(ip, whichfork, offset,
+ &wpc->iomap, whichfork == XFS_COW_FORK ?
&wpc->cow_seq : &wpc->data_seq);
if (error)
return error;
@@ -507,6 +513,7 @@ xfs_map_blocks(
xfs_fileoff_t offset_fsb = XFS_B_TO_FSBT(mp, offset);
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
xfs_fileoff_t cow_fsb = NULLFILEOFF;
+ int whichfork = XFS_DATA_FORK;
struct xfs_bmbt_irec imap;
struct xfs_iext_cursor icur;
int retries = 0;
@@ -555,7 +562,7 @@ xfs_map_blocks(
wpc->cow_seq = READ_ONCE(ip->i_cowfp->if_seq);
xfs_iunlock(ip, XFS_ILOCK_SHARED);

- wpc->fork = XFS_COW_FORK;
+ whichfork = XFS_COW_FORK;
goto allocate_blocks;
}

@@ -578,8 +585,6 @@ xfs_map_blocks(
wpc->data_seq = READ_ONCE(ip->i_df.if_seq);
xfs_iunlock(ip, XFS_ILOCK_SHARED);

- wpc->fork = XFS_DATA_FORK;
-
/* landed in a hole or beyond EOF? */
if (imap.br_startoff > offset_fsb) {
imap.br_blockcount = imap.br_startoff - offset_fsb;
@@ -604,10 +609,10 @@ xfs_map_blocks(
goto allocate_blocks;

xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0);
- trace_xfs_map_blocks_found(ip, offset, count, wpc->fork, &imap);
+ trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap);
return 0;
allocate_blocks:
- error = xfs_convert_blocks(wpc, ip, offset);
+ error = xfs_convert_blocks(wpc, ip, whichfork, offset);
if (error) {
/*
* If we failed to find the extent in the COW fork we might have
@@ -616,7 +621,7 @@ xfs_map_blocks(
* the former case, but prevent additional retries to avoid
* looping forever for the latter case.
*/
- if (error == -EAGAIN && wpc->fork == XFS_COW_FORK && !retries++)
+ if (error == -EAGAIN && whichfork == XFS_COW_FORK && !retries++)
goto retry;
ASSERT(error != -EAGAIN);
return error;
@@ -627,7 +632,7 @@ xfs_map_blocks(
* original delalloc one. Trim the return extent to the next COW
* boundary again to force a re-lookup.
*/
- if (wpc->fork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
+ if (whichfork != XFS_COW_FORK && cow_fsb != NULLFILEOFF) {
loff_t cow_offset = XFS_FSB_TO_B(mp, cow_fsb);

if (cow_offset < wpc->iomap.offset + wpc->iomap.length)
@@ -636,7 +641,7 @@ xfs_map_blocks(

ASSERT(wpc->iomap.offset <= offset);
ASSERT(wpc->iomap.offset + wpc->iomap.length > offset);
- trace_xfs_map_blocks_alloc(ip, offset, count, wpc->fork, &imap);
+ trace_xfs_map_blocks_alloc(ip, offset, count, whichfork, &imap);
return 0;
}

@@ -670,14 +675,14 @@ xfs_submit_ioend(
nofs_flag = memalloc_nofs_save();

/* Convert CoW extents to regular */
- if (!status && ioend->io_fork == XFS_COW_FORK) {
+ if (!status && (ioend->io_flags & IOMAP_F_SHARED)) {
status = xfs_reflink_convert_cow(XFS_I(ioend->io_inode),
ioend->io_offset, ioend->io_size);
}

/* Reserve log space if we might write beyond the on-disk inode size. */
if (!status &&
- (ioend->io_fork == XFS_COW_FORK ||
+ ((ioend->io_flags & IOMAP_F_SHARED) ||
ioend->io_type != IOMAP_UNWRITTEN) &&
xfs_ioend_is_append(ioend) &&
!ioend->io_private)
@@ -724,8 +729,8 @@ xfs_alloc_ioend(

ioend = container_of(bio, struct xfs_ioend, io_inline_bio);
INIT_LIST_HEAD(&ioend->io_list);
- ioend->io_fork = wpc->fork;
ioend->io_type = wpc->iomap.type;
+ ioend->io_flags = wpc->iomap.flags;
ioend->io_inode = inode;
ioend->io_size = 0;
ioend->io_offset = offset;
@@ -759,6 +764,24 @@ xfs_chain_bio(
return new;
}

+static bool
+xfs_can_add_to_ioend(
+ struct xfs_writepage_ctx *wpc,
+ xfs_off_t offset,
+ sector_t sector)
+{
+ if ((wpc->iomap.flags & IOMAP_F_SHARED) !=
+ (wpc->ioend->io_flags & IOMAP_F_SHARED))
+ return false;
+ if (wpc->iomap.type != wpc->ioend->io_type)
+ return false;
+ if (offset != wpc->ioend->io_offset + wpc->ioend->io_size)
+ return false;
+ if (sector != bio_end_sector(wpc->ioend->io_bio))
+ return false;
+ return true;
+}
+
/*
* Test to see if we have an existing ioend structure that we could append to
* first, otherwise finish off the current ioend and start another.
@@ -778,11 +801,7 @@ xfs_add_to_ioend(
unsigned poff = offset & (PAGE_SIZE - 1);
bool merged, same_page = false;

- if (!wpc->ioend ||
- wpc->fork != wpc->ioend->io_fork ||
- wpc->iomap.type != wpc->ioend->io_type ||
- sector != bio_end_sector(wpc->ioend->io_bio) ||
- offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
+ if (!wpc->ioend || !xfs_can_add_to_ioend(wpc, offset, sector)) {
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
wpc->ioend = xfs_alloc_ioend(inode, wpc, offset, sector, wbc);
diff --git a/fs/xfs/xfs_aops.h b/fs/xfs/xfs_aops.h
index 6a45d675dcba..4a0226cdad4f 100644
--- a/fs/xfs/xfs_aops.h
+++ b/fs/xfs/xfs_aops.h
@@ -13,8 +13,8 @@ extern struct bio_set xfs_ioend_bioset;
*/
struct xfs_ioend {
struct list_head io_list; /* next ioend in chain */
- int io_fork; /* inode fork written back */
u16 io_type;
+ u16 io_flags; /* IOMAP_F_* */
struct inode *io_inode; /* file being written to */
size_t io_size; /* size of the extent */
xfs_off_t io_offset; /* offset in the file */
--
2.20.1