From f2c0b07088966c396ddcee54f4bed97cdb01192f Mon Sep 17 00:00:00 2001

From: Jon Maloy <jmaloy@redhat.com>

Date: Tue, 9 Feb 2021 23:14:55 -0500

Subject: [PATCH 2/3] virtiofsd: optionally return inode pointer from

 lo_do_lookup()

RH-Author: Jon Maloy <jmaloy@redhat.com>

Message-id: <20210209231456.1555472-3-jmaloy@redhat.com>

Patchwork-id: 101022

O-Subject: [RHEL-8.4.0 qemu-kvm PATCH 2/3] virtiofsd: optionally return inode pointer from lo_do_lookup()

Bugzilla: 1919111

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Greg Kurz <gkurz@redhat.com>

RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

From: Stefan Hajnoczi <stefanha@redhat.com>

lo_do_lookup() finds an existing inode or allocates a new one. It

increments nlookup so that the inode stays alive until the client

releases it.

Existing callers don't need the struct lo_inode so the function doesn't

return it. Extend the function to optionally return the inode. The next

commit will need it.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Greg Kurz <groug@kaod.org>

Message-Id: <20210204150208.367837-3-stefanha@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry-picked from commit 22d2ece71e533310da31f2857ebc4a00d91968b3)

Signed-off-by: Jon Maloy <jmaloy@redhat.com>

Signed-off-by: Jon Maloy <jmaloy.redhat.com>

---

 tools/virtiofsd/passthrough_ll.c | 29 +++++++++++++++++++++--------

 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c

index 518ba11c47..e5bd3d73e4 100644

--- a/tools/virtiofsd/passthrough_ll.c

+++ b/tools/virtiofsd/passthrough_ll.c

@@ -878,11 +878,13 @@ static void posix_locks_value_destroy(gpointer data)

 }

 /*

- * Increments nlookup and caller must release refcount using

- * lo_inode_put(&parent).

+ * Increments nlookup on the inode on success. unref_inode_lolocked() must be

+ * called eventually to decrement nlookup again. If inodep is non-NULL, the

+ * inode pointer is stored and the caller must call lo_inode_put().

  */

 static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,

-                        struct fuse_entry_param *e)

+                        struct fuse_entry_param *e,

+                        struct lo_inode **inodep)

 {

     int newfd;

     int res;

@@ -891,6 +893,10 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,

     struct lo_inode *inode = NULL;

     struct lo_inode *dir = lo_inode(req, parent);

+    if (inodep) {

+        *inodep = NULL;

+    }

+

     /*

      * name_to_handle_at() and open_by_handle_at() can reach here with fuse

      * mount point in guest, but we don't have its inode info in the

@@ -953,7 +959,14 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,

         pthread_mutex_unlock(&lo->mutex);

     }

     e->ino = inode->fuse_ino;

-    lo_inode_put(lo, &inode;;

+

+    /* Transfer ownership of inode pointer to caller or drop it */

+    if (inodep) {

+        *inodep = inode;

+    } else {

+        lo_inode_put(lo, &inode;;

+    }

+

     lo_inode_put(lo, &dir;;

     fuse_log(FUSE_LOG_DEBUG, "  %lli/%s -> %lli\n", (unsigned long long)parent,

@@ -988,7 +1001,7 @@ static void lo_lookup(fuse_req_t req, fuse_ino_t parent, const char *name)

         return;

     }

-    err = lo_do_lookup(req, parent, name, &e);

+    err = lo_do_lookup(req, parent, name, &e, NULL);

     if (err) {

         fuse_reply_err(req, err);

     } else {

@@ -1098,7 +1111,7 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent,

         goto out;

     }

-    saverr = lo_do_lookup(req, parent, name, &e);

+    saverr = lo_do_lookup(req, parent, name, &e, NULL);

     if (saverr) {

         goto out;

     }

@@ -1599,7 +1612,7 @@ static void lo_do_readdir(fuse_req_t req, fuse_ino_t ino, size_t size,

         if (plus) {

             if (!is_dot_or_dotdot(name)) {

-                err = lo_do_lookup(req, ino, name, &e);

+                err = lo_do_lookup(req, ino, name, &e, NULL);

                 if (err) {

                     goto error;

                 }

@@ -1793,7 +1806,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,

         }

         fi->fh = fh;

-        err = lo_do_lookup(req, parent, name, &e);

+        err = lo_do_lookup(req, parent, name, &e, NULL);

     }

     if (lo->cache == CACHE_NONE) {

         fi->direct_io = 1;

-- 

2.18.2