Fuse client can enable or disable per-file DAX inside guest by
chattr(1). Similarly the new state won't be updated until the file is
closed and reopened later.
It is worth nothing that it is a best-effort style, since whether
per-file DAX is enabled or not is controlled by fuse_attr.flags retrieved
by FUSE LOOKUP routine, while the algorithm constructing fuse_attr.flags
is totally fuse server specific, not to mention ioctl may not be
supported by fuse server at all.
Signed-off-by: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
---
fs/fuse/ioctl.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/fuse/ioctl.c b/fs/fuse/ioctl.c
index 546ea3d58fb4..172e05c3f038 100644
--- a/fs/fuse/ioctl.c
+++ b/fs/fuse/ioctl.c
@@ -460,6 +460,7 @@ int fuse_fileattr_set(struct user_namespace *mnt_userns,
struct fuse_file *ff;
unsigned int flags = fa->flags;
struct fsxattr xfa;
+ bool newdax;
int err;
ff = fuse_priv_ioctl_prepare(inode);
@@ -467,10 +468,9 @@ int fuse_fileattr_set(struct user_namespace *mnt_userns,
return PTR_ERR(ff);
if (fa->flags_valid) {
+ newdax = flags & FS_DAX_FL;
err = fuse_priv_ioctl(inode, ff, FS_IOC_SETFLAGS,
&flags, sizeof(flags));
- if (err)
- goto cleanup;
} else {
memset(&xfa, 0, sizeof(xfa));
xfa.fsx_xflags = fa->fsx_xflags;
@@ -479,11 +479,14 @@ int fuse_fileattr_set(struct user_namespace *mnt_userns,
xfa.fsx_projid = fa->fsx_projid;
xfa.fsx_cowextsize = fa->fsx_cowextsize;
+ newdax = fa->fsx_xflags & FS_XFLAG_DAX;
err = fuse_priv_ioctl(inode, ff, FS_IOC_FSSETXATTR,
&xfa, sizeof(xfa));
}
-cleanup:
+ if (!err && IS_ENABLED(CONFIG_FUSE_DAX))
+ fuse_dax_dontcache(inode, newdax);
+
fuse_priv_ioctl_cleanup(inode, ff);
return err;
--
2.27.0
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