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path: root/fs/xfs/xfs_file.c
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Diffstat (limited to 'fs/xfs/xfs_file.c')
-rw-r--r--fs/xfs/xfs_file.c46
1 files changed, 42 insertions, 4 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index c203839cd5be..3a5d305e60c9 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -569,20 +569,41 @@ restart:
* write. If zeroing is needed and we are currently holding the
* iolock shared, we need to update it to exclusive which implies
* having to redo all checks before.
+ *
+ * We need to serialise against EOF updates that occur in IO
+ * completions here. We want to make sure that nobody is changing the
+ * size while we do this check until we have placed an IO barrier (i.e.
+ * hold the XFS_IOLOCK_EXCL) that prevents new IO from being dispatched.
+ * The spinlock effectively forms a memory barrier once we have the
+ * XFS_IOLOCK_EXCL so we are guaranteed to see the latest EOF value
+ * and hence be able to correctly determine if we need to run zeroing.
*/
+ spin_lock(&ip->i_flags_lock);
if (*pos > i_size_read(inode)) {
bool zero = false;
+ spin_unlock(&ip->i_flags_lock);
if (*iolock == XFS_IOLOCK_SHARED) {
xfs_rw_iunlock(ip, *iolock);
*iolock = XFS_IOLOCK_EXCL;
xfs_rw_ilock(ip, *iolock);
+
+ /*
+ * We now have an IO submission barrier in place, but
+ * AIO can do EOF updates during IO completion and hence
+ * we now need to wait for all of them to drain. Non-AIO
+ * DIO will have drained before we are given the
+ * XFS_IOLOCK_EXCL, and so for most cases this wait is a
+ * no-op.
+ */
+ inode_dio_wait(inode);
goto restart;
}
error = xfs_zero_eof(ip, *pos, i_size_read(inode), &zero);
if (error)
return error;
- }
+ } else
+ spin_unlock(&ip->i_flags_lock);
/*
* Updating the timestamps will grab the ilock again from
@@ -644,6 +665,8 @@ xfs_file_dio_aio_write(
int iolock;
size_t count = iov_iter_count(from);
loff_t pos = iocb->ki_pos;
+ loff_t end;
+ struct iov_iter data;
struct xfs_buftarg *target = XFS_IS_REALTIME_INODE(ip) ?
mp->m_rtdev_targp : mp->m_ddev_targp;
@@ -683,10 +706,11 @@ xfs_file_dio_aio_write(
if (ret)
goto out;
iov_iter_truncate(from, count);
+ end = pos + count - 1;
if (mapping->nrpages) {
ret = filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
- pos, pos + count - 1);
+ pos, end);
if (ret)
goto out;
/*
@@ -696,7 +720,7 @@ xfs_file_dio_aio_write(
*/
ret = invalidate_inode_pages2_range(VFS_I(ip)->i_mapping,
pos >> PAGE_CACHE_SHIFT,
- (pos + count - 1) >> PAGE_CACHE_SHIFT);
+ end >> PAGE_CACHE_SHIFT);
WARN_ON_ONCE(ret);
ret = 0;
}
@@ -713,8 +737,22 @@ xfs_file_dio_aio_write(
}
trace_xfs_file_direct_write(ip, count, iocb->ki_pos, 0);
- ret = generic_file_direct_write(iocb, from, pos);
+ data = *from;
+ ret = mapping->a_ops->direct_IO(WRITE, iocb, &data, pos);
+
+ /* see generic_file_direct_write() for why this is necessary */
+ if (mapping->nrpages) {
+ invalidate_inode_pages2_range(mapping,
+ pos >> PAGE_CACHE_SHIFT,
+ end >> PAGE_CACHE_SHIFT);
+ }
+
+ if (ret > 0) {
+ pos += ret;
+ iov_iter_advance(from, ret);
+ iocb->ki_pos = pos;
+ }
out:
xfs_rw_iunlock(ip, iolock);