Merge tag 'vfs-6.13.untorn.writes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs untorn write support from Christian Brauner:
 "An atomic write is a write issed with torn-write protection. This
  means for a power failure or any hardware failure all or none of the
  data from the write will be stored, never a mix of old and new data.

  This work is already supported for block devices. If a block device is
  opened with O_DIRECT and the block device supports atomic write, then
  FMODE_CAN_ATOMIC_WRITE is added to the file of the opened block
  device.

  This contains the work to expand atomic write support to filesystems,
  specifically ext4 and XFS. Currently, only support for writing exactly
  one filesystem block atomically is added.

  Since it's now possible to have filesystem block size > page size for
  XFS, it's possible to write 4K+ blocks atomically on x86"

* tag 'vfs-6.13.untorn.writes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  iomap: drop an obsolete comment in iomap_dio_bio_iter
  ext4: Do not fallback to buffered-io for DIO atomic write
  ext4: Support setting FMODE_CAN_ATOMIC_WRITE
  ext4: Check for atomic writes support in write iter
  ext4: Add statx support for atomic writes
  xfs: Support setting FMODE_CAN_ATOMIC_WRITE
  xfs: Validate atomic writes
  xfs: Support atomic write for statx
  fs: iomap: Atomic write support
  fs: Export generic_atomic_write_valid()
  block: Add bdev atomic write limits helpers
  fs/block: Check for IOCB_DIRECT in generic_atomic_write_valid()
  block/fs: Pass an iocb to generic_atomic_write_valid()

1 files changed, 10 insertions, 6 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 64dc24afdb3a..3e5dad12a5b4 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1830,18 +1830,22 @@ int generic_file_rw_checks(struct file *file_in, struct file *file_out)
 	return 0;
 }
 
-bool generic_atomic_write_valid(struct iov_iter *iter, loff_t pos)
+int generic_atomic_write_valid(struct kiocb *iocb, struct iov_iter *iter)
 {
 	size_t len = iov_iter_count(iter);
 
 	if (!iter_is_ubuf(iter))
-		return false;
+		return -EINVAL;
 
 	if (!is_power_of_2(len))
-		return false;
+		return -EINVAL;
+
+	if (!IS_ALIGNED(iocb->ki_pos, len))
+		return -EINVAL;
 
-	if (!IS_ALIGNED(pos, len))
-		return false;
+	if (!(iocb->ki_flags & IOCB_DIRECT))
+		return -EOPNOTSUPP;
 
-	return true;
+	return 0;
 }
+EXPORT_SYMBOL_GPL(generic_atomic_write_valid);