From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
If IOCB_NOWAIT is set, bail if the i_rwsem is not lockable
immediately.
IF IOMAP_NOWAIT is set, return EAGAIN in xfs_file_iomap_begin
if it needs allocation either due to file extending, writing to a hole,
or COW.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/xfs/xfs_file.c | 9 +++++++--
fs/xfs/xfs_iomap.c | 9 +++++++++
2 files changed, 16 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index bbb9eb6..7e16a83 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -528,12 +528,17 @@ xfs_file_dio_aio_write(
((iocb->ki_pos + count) & mp->m_blockmask)) {
unaligned_io = 1;
iolock = XFS_IOLOCK_EXCL;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
} else {
iolock = XFS_IOLOCK_SHARED;
}
- xfs_ilock(ip, iolock);
-
+ if (!xfs_ilock_nowait(ip, iolock)) {
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+ xfs_ilock(ip, iolock);
+ }
ret = xfs_file_aio_write_checks(iocb, from, &iolock);
if (ret)
goto out;
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 1aa3abd..84f981a 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1020,6 +1020,11 @@ xfs_file_iomap_begin(
if ((flags & IOMAP_REPORT) ||
(xfs_is_reflink_inode(ip) &&
(flags & IOMAP_WRITE) && (flags & IOMAP_DIRECT))) {
+ /* Allocations due to reflinks */
+ if ((flags & IOMAP_NOWAIT) && !(flags & IOMAP_REPORT)) {
+ error = -EAGAIN;
+ goto out_unlock;
+ }
/* Trim the mapping to the nearest shared extent boundary. */
error = xfs_reflink_trim_around_shared(ip, &imap, &shared,
&trimmed);
@@ -1049,6 +1054,10 @@ xfs_file_iomap_begin(
}
if ((flags & IOMAP_WRITE) && imap_needs_alloc(inode, &imap, nimaps)) {
+ if (flags & IOMAP_NOWAIT) {
+ error = -EAGAIN;
+ goto out_unlock;
+ }
/*
* We cap the maximum length we map here to MAX_WRITEBACK_PAGES
* pages to keep the chunks of work done where somewhat symmetric
--
2.10.2
--
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