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From 9a44d78f5019280b006bb5b3de7164336289d639 Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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Date: Mon, 27 Jan 2020 19:02:21 +0100
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Subject: [PATCH 110/116] virtiofsd: fix lo_destroy() resource leaks
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Message-id: <20200127190227.40942-107-dgilbert@redhat.com>
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Patchwork-id: 93560
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 106/112] virtiofsd: fix lo_destroy() resource leaks
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Bugzilla: 1694164
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RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Sergio Lopez Pascual <slp@redhat.com>
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Now that lo_destroy() is serialized we can call unref_inode() so that
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all inode resources are freed.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 28f7a3b026f231bfe8de5fed6a18a8d27b1dfcee)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 tools/virtiofsd/passthrough_ll.c | 41 ++++++++++++++++++++--------------------
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 1 file changed, 20 insertions(+), 21 deletions(-)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index 79b8b71..eb001b9 100644
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--- a/tools/virtiofsd/passthrough_ll.c
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+++ b/tools/virtiofsd/passthrough_ll.c
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@@ -1371,26 +1371,6 @@ static void unref_inode_lolocked(struct lo_data *lo, struct lo_inode *inode,
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     }
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 }
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-static int unref_all_inodes_cb(gpointer key, gpointer value, gpointer user_data)
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-{
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-    struct lo_inode *inode = value;
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-    struct lo_data *lo = user_data;
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-
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-    inode->nlookup = 0;
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-    lo_map_remove(&lo->ino_map, inode->fuse_ino);
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-    close(inode->fd);
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-    lo_inode_put(lo, &inode); /* Drop our refcount from lo_do_lookup() */
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-
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-    return TRUE;
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-}
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-
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-static void unref_all_inodes(struct lo_data *lo)
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-{
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-    pthread_mutex_lock(&lo->mutex);
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-    g_hash_table_foreach_remove(lo->inodes, unref_all_inodes_cb, lo);
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-    pthread_mutex_unlock(&lo->mutex);
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-}
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-
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 static void lo_forget_one(fuse_req_t req, fuse_ino_t ino, uint64_t nlookup)
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 {
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     struct lo_data *lo = lo_data(req);
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@@ -2477,7 +2457,26 @@ static void lo_lseek(fuse_req_t req, fuse_ino_t ino, off_t off, int whence,
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 static void lo_destroy(void *userdata)
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 {
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     struct lo_data *lo = (struct lo_data *)userdata;
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-    unref_all_inodes(lo);
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+
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+    /*
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+     * Normally lo->mutex must be taken when traversing lo->inodes but
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+     * lo_destroy() is a serialized request so no races are possible here.
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+     *
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+     * In addition, we cannot acquire lo->mutex since unref_inode() takes it
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+     * too and this would result in a recursive lock.
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+     */
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+    while (true) {
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+        GHashTableIter iter;
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+        gpointer key, value;
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+
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+        g_hash_table_iter_init(&iter, lo->inodes);
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+        if (!g_hash_table_iter_next(&iter, &key, &value)) {
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+            break;
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+        }
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+
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+        struct lo_inode *inode = value;
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+        unref_inode_lolocked(lo, inode, inode->nlookup);
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+    }
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 }
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 static struct fuse_lowlevel_ops lo_oper = {
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-- 
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1.8.3.1
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