* FUSE_DAX_FMAP flag in INIT request/reply
* fuse_conn->famfs_iomap (enable famfs-mapped files) to denote a
famfs-enabled connection
Signed-off-by: John Groves <j...@groves.net>
---
fs/fuse/fuse_i.h | 3 +++
fs/fuse/inode.c | 14 ++++++++++++++
include/uapi/linux/fuse.h | 4 ++++
3 files changed, 21 insertions(+)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 9d87ac48d724..a592c1002861 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -873,6 +873,9 @@ struct fuse_conn {
/* Use io_uring for communication */
unsigned int io_uring;
+ /* dev_dax_iomap support for famfs */
+ unsigned int famfs_iomap:1;
+
/** Maximum stack depth for passthrough backing files */
int max_stack_depth;
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 29147657a99f..e48e11c3f9f3 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -1392,6 +1392,18 @@ static void process_init_reply(struct fuse_mount *fm,
struct fuse_args *args,
}
if (flags & FUSE_OVER_IO_URING && fuse_uring_enabled())
fc->io_uring = 1;
+ if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX) &&
+ flags & FUSE_DAX_FMAP) {
+ /* XXX: Should also check that fuse server
+ * has CAP_SYS_RAWIO and/or CAP_SYS_ADMIN,
+ * since it is directing the kernel to access
+ * dax memory directly - but this function
+ * appears not to be called in fuse server
+ * process context (b/c even if it drops
+ * those capabilities, they are held here).
+ */
+ fc->famfs_iomap = 1;
+ }
} else {
ra_pages = fc->max_read / PAGE_SIZE;
fc->no_lock = 1;
@@ -1450,6 +1462,8 @@ void fuse_send_init(struct fuse_mount *fm)
flags |= FUSE_SUBMOUNTS;
if (IS_ENABLED(CONFIG_FUSE_PASSTHROUGH))
flags |= FUSE_PASSTHROUGH;
+ if (IS_ENABLED(CONFIG_FUSE_FAMFS_DAX))
+ flags |= FUSE_DAX_FMAP;
/*
* This is just an information flag for fuse server. No need to check
diff --git a/include/uapi/linux/fuse.h b/include/uapi/linux/fuse.h
index 5e0eb41d967e..6c384640c79b 100644
--- a/include/uapi/linux/fuse.h
+++ b/include/uapi/linux/fuse.h
@@ -229,6 +229,8 @@
* - FUSE_URING_IN_OUT_HEADER_SZ
* - FUSE_URING_OP_IN_OUT_SZ
* - enum fuse_uring_cmd
+ * 7.43
+ * - Add FUSE_DAX_FMAP capability - ability to handle in-kernel fsdax maps
*/
#ifndef _LINUX_FUSE_H
@@ -435,6 +437,7 @@ struct fuse_file_lock {
* of the request ID indicates resend requests
* FUSE_ALLOW_IDMAP: allow creation of idmapped mounts
* FUSE_OVER_IO_URING: Indicate that client supports io-uring
+ * FUSE_DAX_FMAP: kernel supports dev_dax_iomap (aka famfs) fmaps
*/
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
@@ -482,6 +485,7 @@ struct fuse_file_lock {
#define FUSE_DIRECT_IO_RELAX FUSE_DIRECT_IO_ALLOW_MMAP
#define FUSE_ALLOW_IDMAP (1ULL << 40)
#define FUSE_OVER_IO_URING (1ULL << 41)
+#define FUSE_DAX_FMAP (1ULL << 42)
/**
* CUSE INIT request/reply flags
--
2.49.0
