[RFC PATCH v3 05/18] xfs: Add iomap async buffered write support

Stefan Roesch
2022-05-18T23:37:43Z

This adds the async buffered write support to the iomap layer of XFS. If
a lock cannot be acquired or additional reads need to be performed, the
request will return -EAGAIN in case this is an async buffered write
request.

This patch changes the helper function xfs_ilock_for_iomap such that the
lock mode needs to be passed in.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
fs/xfs/xfs_iomap.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index e552ce541ec2..1aea962262ad 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -659,7 +659,7 @@ xfs_ilock_for_iomap(
unsigned flags,
unsigned *lockmode)
{
- unsigned mode = XFS_ILOCK_SHARED;
+ unsigned int mode = *lockmode;
bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);

/*
@@ -737,7 +737,7 @@ xfs_direct_write_iomap_begin(
int nimaps = 1, error = 0;
bool shared = false;
u16 iomap_flags = 0;
- unsigned lockmode;
+ unsigned int lockmode = XFS_ILOCK_SHARED;

ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));

@@ -881,18 +881,22 @@ xfs_buffered_write_iomap_begin(
bool eof = false, cow_eof = false, shared = false;
int allocfork = XFS_DATA_FORK;
int error = 0;
+ unsigned int lockmode = XFS_ILOCK_EXCL;

if (xfs_is_shutdown(mp))
return -EIO;

/* we can't use delayed allocations when using extent size hints */
- if (xfs_get_extsz_hint(ip))
+ if (xfs_get_extsz_hint(ip)) {
return xfs_direct_write_iomap_begin(inode, offset, count,
flags, iomap, srcmap);
+ }

ASSERT(!XFS_IS_REALTIME_INODE(ip));

- xfs_ilock(ip, XFS_ILOCK_EXCL);
+ error = xfs_ilock_for_iomap(ip, flags, &lockmode);
+ if (error)
+ return error;

if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(&ip->i_df)) ||
XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
@@ -1167,7 +1171,7 @@ xfs_read_iomap_begin(
xfs_fileoff_t end_fsb = xfs_iomap_end_fsb(mp, offset, length);
int nimaps = 1, error = 0;
bool shared = false;
- unsigned lockmode;
+ unsigned int lockmode = XFS_ILOCK_SHARED;

ASSERT(!(flags & (IOMAP_WRITE | IOMAP_ZERO)));

--
2.30.2