The per inode DAX feature in ext4/xfs uses the persistent inode flag, i.e. FS_DAX_FL/FS_XFLAG_DAX, to indicate if DAX shall be enabled for this file or not when filesystem is mounted in per inode DAX mode.
To keep compatible with this feature in ext4/xfs, virtiofs also supports enabling DAX depending on the persistent inode flag, which may be set/cleared by users inside guest or admin on host. This policy is used when '-o dax=inode' option is specified for virtiofsd. Signed-off-by: Jeffle Xu <[email protected]> --- tools/virtiofsd/passthrough_ll.c | 33 ++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index 999c906da2..dac5063594 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -1026,6 +1026,35 @@ static int do_statx(struct lo_data *lo, int dirfd, const char *pathname, return 0; } +static bool lo_should_enable_dax(struct lo_data *lo, struct lo_inode *inode, + struct fuse_entry_param *e) +{ + if (lo->dax == INODE_DAX_NONE || !S_ISREG(e->attr.st_mode)) { + return false; + } + + if (lo->dax == INODE_DAX_INODE) { + int res, fd; + int ret = false; + unsigned int attr; + + fd = lo_inode_open(lo, inode, O_RDONLY); + if (fd == -1) { + return false; + } + + res = ioctl(fd, FS_IOC_GETFLAGS, &attr); + if (!res && (attr & FS_DAX_FL)) { + ret = true; + } + + close(fd); + return ret; + } + + return false; +} + /* * Increments nlookup on the inode on success. unref_inode_lolocked() must be * called eventually to decrement nlookup again. If inodep is non-NULL, the @@ -1116,6 +1145,10 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name, } e->ino = inode->fuse_ino; + if (lo_should_enable_dax(lo, inode, e)) { + e->attr_flags |= FUSE_ATTR_DAX; + } + /* Transfer ownership of inode pointer to caller or drop it */ if (inodep) { *inodep = inode; -- 2.27.0 _______________________________________________ Virtio-fs mailing list [email protected] https://listman.redhat.com/mailman/listinfo/virtio-fs
