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Blame SOURCES/kvm-virtiofsd-passthrough_ll-add-ino_map-to-hide-lo_inod.patch

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From d81396cc3d9815730903b0755c9d2e67d6954d54 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 19:01:14 +0100
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Subject: [PATCH 043/116] virtiofsd: passthrough_ll: add ino_map to hide
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 lo_inode pointers
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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: <20200127190227.40942-40-dgilbert@redhat.com>
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Patchwork-id: 93493
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 039/112] virtiofsd: passthrough_ll: add ino_map to hide lo_inode pointers
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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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Do not expose lo_inode pointers to clients.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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(cherry picked from commit 92fb57b83cdbfc4bf53c0c46a3d0bcbc36e64126)
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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 | 144 +++++++++++++++++++++++++++++++--------
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 1 file changed, 114 insertions(+), 30 deletions(-)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index e83a976..a3ebf74 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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@@ -57,8 +57,8 @@
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 #include "passthrough_helpers.h"
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 /*
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- * We are re-using pointers to our `struct lo_inode` and `struct
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- * lo_dirp` elements as inodes. This means that we must be able to
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+ * We are re-using pointers to our `struct lo_inode`
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+ * elements as inodes. This means that we must be able to
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  * store uintptr_t values in a fuse_ino_t variable. The following
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  * incantation checks this condition at compile time.
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  */
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@@ -76,7 +76,7 @@ struct _uintptr_to_must_hold_fuse_ino_t_dummy_struct {
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 struct lo_map_elem {
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     union {
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-        /* Element values will go here... */
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+        struct lo_inode *inode;
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         ssize_t freelist;
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     };
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     bool in_use;
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@@ -97,6 +97,7 @@ struct lo_inode {
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     ino_t ino;
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     dev_t dev;
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     uint64_t refcount; /* protected by lo->mutex */
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+    fuse_ino_t fuse_ino;
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 };
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 struct lo_cred {
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@@ -121,6 +122,7 @@ struct lo_data {
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     int cache;
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     int timeout_set;
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     struct lo_inode root; /* protected by lo->mutex */
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+    struct lo_map ino_map; /* protected by lo->mutex */
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 };
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 static const struct fuse_opt lo_opts[] = {
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@@ -145,14 +147,14 @@ static struct lo_data *lo_data(fuse_req_t req)
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     return (struct lo_data *)fuse_req_userdata(req);
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 }
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-__attribute__((unused)) static void lo_map_init(struct lo_map *map)
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+static void lo_map_init(struct lo_map *map)
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 {
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     map->elems = NULL;
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     map->nelems = 0;
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     map->freelist = -1;
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 }
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-__attribute__((unused)) static void lo_map_destroy(struct lo_map *map)
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+static void lo_map_destroy(struct lo_map *map)
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 {
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     free(map->elems);
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 }
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@@ -183,8 +185,7 @@ static int lo_map_grow(struct lo_map *map, size_t new_nelems)
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     return 1;
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 }
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-__attribute__((unused)) static struct lo_map_elem *
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-lo_map_alloc_elem(struct lo_map *map)
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+static struct lo_map_elem *lo_map_alloc_elem(struct lo_map *map)
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 {
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     struct lo_map_elem *elem;
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@@ -200,8 +201,7 @@ lo_map_alloc_elem(struct lo_map *map)
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     return elem;
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 }
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-__attribute__((unused)) static struct lo_map_elem *
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-lo_map_reserve(struct lo_map *map, size_t key)
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+static struct lo_map_elem *lo_map_reserve(struct lo_map *map, size_t key)
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 {
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     ssize_t *prev;
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@@ -222,8 +222,7 @@ lo_map_reserve(struct lo_map *map, size_t key)
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     return NULL;
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 }
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-__attribute__((unused)) static struct lo_map_elem *
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-lo_map_get(struct lo_map *map, size_t key)
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+static struct lo_map_elem *lo_map_get(struct lo_map *map, size_t key)
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 {
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     if (key >= map->nelems) {
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         return NULL;
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@@ -234,8 +233,7 @@ lo_map_get(struct lo_map *map, size_t key)
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     return &map->elems[key];
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 }
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-__attribute__((unused)) static void lo_map_remove(struct lo_map *map,
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-                                                  size_t key)
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+static void lo_map_remove(struct lo_map *map, size_t key)
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 {
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     struct lo_map_elem *elem;
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@@ -254,18 +252,40 @@ __attribute__((unused)) static void lo_map_remove(struct lo_map *map,
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     map->freelist = key;
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 }
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+/* Assumes lo->mutex is held */
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+static ssize_t lo_add_inode_mapping(fuse_req_t req, struct lo_inode *inode)
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+{
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+    struct lo_map_elem *elem;
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+
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+    elem = lo_map_alloc_elem(&lo_data(req)->ino_map);
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+    if (!elem) {
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+        return -1;
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+    }
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+
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+    elem->inode = inode;
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+    return elem - lo_data(req)->ino_map.elems;
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+}
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+
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 static struct lo_inode *lo_inode(fuse_req_t req, fuse_ino_t ino)
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 {
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-    if (ino == FUSE_ROOT_ID) {
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-        return &lo_data(req)->root;
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-    } else {
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-        return (struct lo_inode *)(uintptr_t)ino;
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+    struct lo_data *lo = lo_data(req);
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+    struct lo_map_elem *elem;
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+
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+    pthread_mutex_lock(&lo->mutex);
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+    elem = lo_map_get(&lo->ino_map, ino);
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+    pthread_mutex_unlock(&lo->mutex);
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+
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+    if (!elem) {
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+        return NULL;
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     }
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+
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+    return elem->inode;
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 }
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 static int lo_fd(fuse_req_t req, fuse_ino_t ino)
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 {
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-    return lo_inode(req, ino)->fd;
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+    struct lo_inode *inode = lo_inode(req, ino);
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+    return inode ? inode->fd : -1;
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 }
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 static bool lo_debug(fuse_req_t req)
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@@ -337,10 +357,18 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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 {
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     int saverr;
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     char procname[64];
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-    struct lo_inode *inode = lo_inode(req, ino);
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-    int ifd = inode->fd;
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+    struct lo_inode *inode;
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+    int ifd;
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     int res;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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+    ifd = inode->fd;
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+
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     if (valid & FUSE_SET_ATTR_MODE) {
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         if (fi) {
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             res = fchmod(fi->fh, attr->st_mode);
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@@ -470,6 +498,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
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         inode->dev = e->attr.st_dev;
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         pthread_mutex_lock(&lo->mutex);
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+        inode->fuse_ino = lo_add_inode_mapping(req, inode);
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         prev = &lo->root;
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         next = prev->next;
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         next->prev = inode;
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@@ -478,7 +507,7 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
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         prev->next = inode;
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         pthread_mutex_unlock(&lo->mutex);
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     }
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-    e->ino = (uintptr_t)inode;
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+    e->ino = inode->fuse_ino;
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     if (lo_debug(req)) {
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         fuse_log(FUSE_LOG_DEBUG, "  %lli/%s -> %lli\n",
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@@ -582,10 +611,16 @@ static void lo_mknod_symlink(fuse_req_t req, fuse_ino_t parent,
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 {
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     int res;
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     int saverr;
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-    struct lo_inode *dir = lo_inode(req, parent);
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+    struct lo_inode *dir;
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     struct fuse_entry_param e;
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     struct lo_cred old = {};
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+    dir = lo_inode(req, parent);
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+    if (!dir) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     saverr = ENOMEM;
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     saverr = lo_change_cred(req, &old;;
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@@ -663,10 +698,16 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent,
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 {
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     int res;
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     struct lo_data *lo = lo_data(req);
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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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     struct fuse_entry_param e;
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     int saverr;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     memset(&e, 0, sizeof(struct fuse_entry_param));
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     e.attr_timeout = lo->timeout;
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     e.entry_timeout = lo->timeout;
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@@ -684,7 +725,7 @@ static void lo_link(fuse_req_t req, fuse_ino_t ino, fuse_ino_t parent,
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     pthread_mutex_lock(&lo->mutex);
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     inode->refcount++;
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     pthread_mutex_unlock(&lo->mutex);
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-    e.ino = (uintptr_t)inode;
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+    e.ino = inode->fuse_ino;
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     if (lo_debug(req)) {
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         fuse_log(FUSE_LOG_DEBUG, "  %lli/%s -> %lli\n",
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@@ -750,10 +791,10 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n)
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         next->prev = prev;
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         prev->next = next;
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+        lo_map_remove(&lo->ino_map, inode->fuse_ino);
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         pthread_mutex_unlock(&lo->mutex);
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         close(inode->fd);
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         free(inode);
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-
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     } else {
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         pthread_mutex_unlock(&lo->mutex);
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     }
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@@ -762,7 +803,12 @@ static void unref_inode(struct lo_data *lo, struct lo_inode *inode, uint64_t n)
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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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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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+
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        return;
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+    }
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     if (lo_debug(req)) {
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         fuse_log(FUSE_LOG_DEBUG, "  forget %lli %lli -%lli\n",
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@@ -1244,10 +1290,16 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
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 {
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     char *value = NULL;
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     char procname[64];
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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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     ssize_t ret;
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     int saverr;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     saverr = ENOSYS;
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     if (!lo_data(req)->xattr) {
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         goto out;
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@@ -1306,10 +1358,16 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
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 {
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     char *value = NULL;
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     char procname[64];
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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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     ssize_t ret;
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     int saverr;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     saverr = ENOSYS;
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     if (!lo_data(req)->xattr) {
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         goto out;
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@@ -1367,10 +1425,16 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
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                         const char *value, size_t size, int flags)
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 {
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     char procname[64];
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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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     ssize_t ret;
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     int saverr;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     saverr = ENOSYS;
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     if (!lo_data(req)->xattr) {
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         goto out;
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@@ -1400,10 +1464,16 @@ out:
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 static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name)
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 {
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     char procname[64];
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-    struct lo_inode *inode = lo_inode(req, ino);
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+    struct lo_inode *inode;
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     ssize_t ret;
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     int saverr;
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+    inode = lo_inode(req, ino);
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+    if (!inode) {
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+        fuse_reply_err(req, EBADF);
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+        return;
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+    }
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+
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     saverr = ENOSYS;
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     if (!lo_data(req)->xattr) {
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         goto out;
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@@ -1522,6 +1592,7 @@ int main(int argc, char *argv[])
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     struct fuse_session *se;
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     struct fuse_cmdline_opts opts;
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     struct lo_data lo = { .debug = 0, .writeback = 0 };
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+    struct lo_map_elem *root_elem;
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     int ret = -1;
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     /* Don't mask creation mode, kernel already did that */
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@@ -1530,8 +1601,19 @@ int main(int argc, char *argv[])
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     pthread_mutex_init(&lo.mutex, NULL);
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     lo.root.next = lo.root.prev = &lo.root;
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     lo.root.fd = -1;
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+    lo.root.fuse_ino = FUSE_ROOT_ID;
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     lo.cache = CACHE_NORMAL;
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+    /*
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+     * Set up the ino map like this:
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+     * [0] Reserved (will not be used)
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+     * [1] Root inode
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+     */
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+    lo_map_init(&lo.ino_map);
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+    lo_map_reserve(&lo.ino_map, 0)->in_use = false;
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+    root_elem = lo_map_reserve(&lo.ino_map, lo.root.fuse_ino);
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+    root_elem->inode = &lo.root;
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+
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     if (fuse_parse_cmdline(&args, &opts) != 0) {
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         return 1;
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     }
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@@ -1628,6 +1710,8 @@ err_out2:
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 err_out1:
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     fuse_opt_free_args(&args);
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+    lo_map_destroy(&lo.ino_map);
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+
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     if (lo.root.fd >= 0) {
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         close(lo.root.fd);
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     }
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-- 
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1.8.3.1
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