This patchset adds support of per-file DAX for virtiofs, which is
inspired by Ira Weiny's work on ext4[1] and xfs[2].
There are three related scenarios:
1. Alloc inode: get per-file DAX flag from fuse_attr.flags. (patch 3)
2. Per-file DAX flag changes when the file has been opened. (patch 3)
In this case, the dentry and inode are all marked as DONT_CACHE, and
the DAX state won't be updated until the file is closed and reopened
later.
3. Users can change the per-file DAX flag inside the guest by chattr(1).
(patch 4)
4. Create new files under directories with DAX enabled. When creating
new files in ext4/xfs on host, the new created files will inherit the
per-file DAX flag from the directory, and thus the new created files in
virtiofs will also inherit the per-file DAX flag if the fuse server
derives fuse_attr.flags from the underlying ext4/xfs inode's per-file
DAX flag.
Any comment is welcome.
[1] commit 9cb20f94afcd ("fs/ext4: Make DAX mount option a tri-state")
[2] commit 02beb2686ff9 ("fs/xfs: Make DAX mount option a tri-state")
changes since v1:
- add support for changing per-file DAX flags inside guest (patch 4)
v1:https://www.spinics.net/lists/linux-virtualization/msg51008.html
Jeffle Xu (4):
fuse: add fuse_should_enable_dax() helper
fuse: Make DAX mount option a tri-state
fuse: add per-file DAX flag
fuse: support changing per-file DAX flag inside guest
fs/fuse/dax.c | 36 ++++++++++++++++++++++++++++++++++--
fs/fuse/file.c | 4 ++--
fs/fuse/fuse_i.h | 16 ++++++++++++----
fs/fuse/inode.c | 7 +++++--
fs/fuse/ioctl.c | 9 ++++++---
fs/fuse/virtio_fs.c | 16 ++++++++++++++--
include/uapi/linux/fuse.h | 5 +++++
7 files changed, 78 insertions(+), 15 deletions(-)
--
2.27.0
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