From: Darrick J. Wong <djwong@xxxxxxxxxx>
At unmount time, there are a few things that we need to ask the fuse
server to do.
First, we need to flush queued events to userspace to give the fuse
server a chance to process the events. This is how we make sure that
the server processes FUSE_RELEASE events before the connection goes
down.
Second, to ensure that all those metadata updates are persisted to disk
before tell the fuse server to destroy itself, send FUSE_SYNCFS after
waiting for the queued events.
Finally, we need to send FUSE_DESTROY to the fuse server so that it
closes the filesystem and the device fds before unmount returns. That
way, a script that does something like "umount /dev/sda ; e2fsck -fn
/dev/sda" will not fail the e2fsck because the fd closure races with
e2fsck startup. Obviously, we need to wait for FUSE_SYNCFS.
This is a major behavior change and who knows what might break existing
code, so we hide it behind iomap mode.
Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
---
fs/fuse/fuse_i.h | 7 +++++++
fs/fuse/file_iomap.c | 29 +++++++++++++++++++++++++++++
fs/fuse/inode.c | 9 +++++++--
3 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index f4834a02d16c98..6a155bdd389af6 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -1364,6 +1364,9 @@ int fuse_init_fs_context_submount(struct fs_context *fsc);
*/
void fuse_conn_destroy(struct fuse_mount *fm);
+/* Send the FUSE_DESTROY command. */
+void fuse_send_destroy(struct fuse_mount *fm);
+
/* Drop the connection and free the fuse mount */
void fuse_mount_destroy(struct fuse_mount *fm);
@@ -1646,11 +1649,15 @@ static inline bool fuse_has_iomap(const struct inode *inode)
int fuse_iomap_backing_open(struct fuse_conn *fc, struct fuse_backing *fb);
int fuse_iomap_backing_close(struct fuse_conn *fc, struct fuse_backing *fb);
+void fuse_iomap_mount(struct fuse_mount *fm);
+void fuse_iomap_unmount(struct fuse_mount *fm);
#else
# define fuse_iomap_enabled(...) (false)
# define fuse_has_iomap(...) (false)
# define fuse_iomap_backing_open(...) (-EOPNOTSUPP)
# define fuse_iomap_backing_close(...) (-EOPNOTSUPP)
+# define fuse_iomap_mount(...) ((void)0)
+# define fuse_iomap_unmount(...) ((void)0)
#endif
#endif /* _FS_FUSE_I_H */
diff --git a/fs/fuse/file_iomap.c b/fs/fuse/file_iomap.c
index 154c99399f48d2..6e0e222da3046c 100644
--- a/fs/fuse/file_iomap.c
+++ b/fs/fuse/file_iomap.c
@@ -593,3 +593,32 @@ int fuse_iomap_backing_close(struct fuse_conn *fc, struct fuse_backing *fb)
/* We only support closing iomap block devices at unmount */
return -EBUSY;
}
+
+void fuse_iomap_mount(struct fuse_mount *fm)
+{
+ struct fuse_conn *fc = fm->fc;
+
+ /*
+ * Enable syncfs for iomap fuse servers so that we can send a final
+ * flush at unmount time. This also means that we can support
+ * freeze/thaw properly.
+ */
+ fc->sync_fs = true;
+}
+
+void fuse_iomap_unmount(struct fuse_mount *fm)
+{
+ struct fuse_conn *fc = fm->fc;
+
+ /*
+ * Flush all pending commands, syncfs, flush that, and send a destroy
+ * command. This gives the fuse server a chance to process all the
+ * pending releases, write the last bits of metadata changes to disk,
+ * and close the iomap block devices before we return from the umount
+ * call. The caller already flushed previously pending requests, so we
+ * only need the flush to wait for syncfs.
+ */
+ sync_filesystem(fm->sb);
+ fuse_flush_requests_and_wait(fc, secs_to_jiffies(60));
+ fuse_send_destroy(fm);
+}
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 1f3f91981410aa..3274ee1c31b62b 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -621,7 +621,7 @@ static void fuse_umount_begin(struct super_block *sb)
retire_super(sb);
}
-static void fuse_send_destroy(struct fuse_mount *fm)
+void fuse_send_destroy(struct fuse_mount *fm)
{
if (fm->fc->conn_init) {
FUSE_ARGS(args);
@@ -1457,6 +1457,9 @@ static void process_init_reply(struct fuse_mount *fm, struct fuse_args *args,
init_server_timeout(fc, timeout);
+ if (fc->iomap)
+ fuse_iomap_mount(fm);
+
fm->sb->s_bdi->ra_pages =
min(fm->sb->s_bdi->ra_pages, ra_pages);
fc->minor = arg->minor;
@@ -2055,7 +2058,9 @@ void fuse_conn_destroy(struct fuse_mount *fm)
struct fuse_conn *fc = fm->fc;
fuse_flush_requests_and_wait(fc, secs_to_jiffies(30));
- if (fc->destroy)
+ if (fc->iomap)
+ fuse_iomap_unmount(fm);
+ else if (fc->destroy)
fuse_send_destroy(fm);
fuse_abort_conn(fc);
