Both lo_open() and lo_create() have similar code to open a file. Extract
a common lo_do_open() function from lo_open() that will be used by
lo_create() in a later commit.

Since lo_do_open() does not otherwise need fuse_req_t req, convert
lo_add_fd_mapping() to use struct lo_data *lo instead.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
v4:
 * Return positive errno if openat(2) fails in lo_do_open() [Greg]
---
 tools/virtiofsd/passthrough_ll.c | 73 ++++++++++++++++++++------------
 1 file changed, 46 insertions(+), 27 deletions(-)

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 5fb36d9407..f14fa5124d 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -459,17 +459,17 @@ static void lo_map_remove(struct lo_map *map, size_t key)
 }
 
 /* Assumes lo->mutex is held */
-static ssize_t lo_add_fd_mapping(fuse_req_t req, int fd)
+static ssize_t lo_add_fd_mapping(struct lo_data *lo, int fd)
 {
     struct lo_map_elem *elem;
 
-    elem = lo_map_alloc_elem(&lo_data(req)->fd_map);
+    elem = lo_map_alloc_elem(&lo->fd_map);
     if (!elem) {
         return -1;
     }
 
     elem->fd = fd;
-    return elem - lo_data(req)->fd_map.elems;
+    return elem - lo->fd_map.elems;
 }
 
 /* Assumes lo->mutex is held */
@@ -1651,6 +1651,38 @@ static void update_open_flags(int writeback, int allow_direct_io,
     }
 }
 
+static int lo_do_open(struct lo_data *lo, struct lo_inode *inode,
+                      struct fuse_file_info *fi)
+{
+    char buf[64];
+    ssize_t fh;
+    int fd;
+
+    update_open_flags(lo->writeback, lo->allow_direct_io, fi);
+
+    sprintf(buf, "%i", inode->fd);
+    fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
+    if (fd == -1) {
+        return errno;
+    }
+
+    pthread_mutex_lock(&lo->mutex);
+    fh = lo_add_fd_mapping(lo, fd);
+    pthread_mutex_unlock(&lo->mutex);
+    if (fh == -1) {
+        close(fd);
+        return ENOMEM;
+    }
+
+    fi->fh = fh;
+    if (lo->cache == CACHE_NONE) {
+        fi->direct_io = 1;
+    } else if (lo->cache == CACHE_ALWAYS) {
+        fi->keep_cache = 1;
+    }
+    return 0;
+}
+
 static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
                       mode_t mode, struct fuse_file_info *fi)
 {
@@ -1691,7 +1723,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
         ssize_t fh;
 
         pthread_mutex_lock(&lo->mutex);
-        fh = lo_add_fd_mapping(req, fd);
+        fh = lo_add_fd_mapping(lo, fd);
         pthread_mutex_unlock(&lo->mutex);
         if (fh == -1) {
             close(fd);
@@ -1892,38 +1924,25 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
 
 static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
 {
-    int fd;
-    ssize_t fh;
-    char buf[64];
     struct lo_data *lo = lo_data(req);
+    struct lo_inode *inode = lo_inode(req, ino);
+    int err;
 
     fuse_log(FUSE_LOG_DEBUG, "lo_open(ino=%" PRIu64 ", flags=%d)\n", ino,
              fi->flags);
 
-    update_open_flags(lo->writeback, lo->allow_direct_io, fi);
-
-    sprintf(buf, "%i", lo_fd(req, ino));
-    fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
-    if (fd == -1) {
-        return (void)fuse_reply_err(req, errno);
-    }
-
-    pthread_mutex_lock(&lo->mutex);
-    fh = lo_add_fd_mapping(req, fd);
-    pthread_mutex_unlock(&lo->mutex);
-    if (fh == -1) {
-        close(fd);
-        fuse_reply_err(req, ENOMEM);
+    if (!inode) {
+        fuse_reply_err(req, EBADF);
         return;
     }
 
-    fi->fh = fh;
-    if (lo->cache == CACHE_NONE) {
-        fi->direct_io = 1;
-    } else if (lo->cache == CACHE_ALWAYS) {
-        fi->keep_cache = 1;
+    err = lo_do_open(lo, inode, fi);
+    lo_inode_put(lo, &inode);
+    if (err) {
+        fuse_reply_err(req, err);
+    } else {
+        fuse_reply_open(req, fi);
     }
-    fuse_reply_open(req, fi);
 }
 
 static void lo_release(fuse_req_t req, fuse_ino_t ino,
-- 
2.29.2

On Thu,  4 Feb 2021 15:02:06 +0000
Stefan Hajnoczi <stefanha@redhat.com> wrote:

> Both lo_open() and lo_create() have similar code to open a file. Extract
> a common lo_do_open() function from lo_open() that will be used by
> lo_create() in a later commit.
> 
> Since lo_do_open() does not otherwise need fuse_req_t req, convert
> lo_add_fd_mapping() to use struct lo_data *lo instead.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---

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

> v4:
>  * Return positive errno if openat(2) fails in lo_do_open() [Greg]
> ---
>  tools/virtiofsd/passthrough_ll.c | 73 ++++++++++++++++++++------------
>  1 file changed, 46 insertions(+), 27 deletions(-)
> 
> diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
> index 5fb36d9407..f14fa5124d 100644
> --- a/tools/virtiofsd/passthrough_ll.c
> +++ b/tools/virtiofsd/passthrough_ll.c
> @@ -459,17 +459,17 @@ static void lo_map_remove(struct lo_map *map, size_t key)
>  }
>  
>  /* Assumes lo->mutex is held */
> -static ssize_t lo_add_fd_mapping(fuse_req_t req, int fd)
> +static ssize_t lo_add_fd_mapping(struct lo_data *lo, int fd)
>  {
>      struct lo_map_elem *elem;
>  
> -    elem = lo_map_alloc_elem(&lo_data(req)->fd_map);
> +    elem = lo_map_alloc_elem(&lo->fd_map);
>      if (!elem) {
>          return -1;
>      }
>  
>      elem->fd = fd;
> -    return elem - lo_data(req)->fd_map.elems;
> +    return elem - lo->fd_map.elems;
>  }
>  
>  /* Assumes lo->mutex is held */
> @@ -1651,6 +1651,38 @@ static void update_open_flags(int writeback, int allow_direct_io,
>      }
>  }
>  
> +static int lo_do_open(struct lo_data *lo, struct lo_inode *inode,
> +                      struct fuse_file_info *fi)
> +{
> +    char buf[64];
> +    ssize_t fh;
> +    int fd;
> +
> +    update_open_flags(lo->writeback, lo->allow_direct_io, fi);
> +
> +    sprintf(buf, "%i", inode->fd);
> +    fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
> +    if (fd == -1) {
> +        return errno;
> +    }
> +
> +    pthread_mutex_lock(&lo->mutex);
> +    fh = lo_add_fd_mapping(lo, fd);
> +    pthread_mutex_unlock(&lo->mutex);
> +    if (fh == -1) {
> +        close(fd);
> +        return ENOMEM;
> +    }
> +
> +    fi->fh = fh;
> +    if (lo->cache == CACHE_NONE) {
> +        fi->direct_io = 1;
> +    } else if (lo->cache == CACHE_ALWAYS) {
> +        fi->keep_cache = 1;
> +    }
> +    return 0;
> +}
> +
>  static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
>                        mode_t mode, struct fuse_file_info *fi)
>  {
> @@ -1691,7 +1723,7 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
>          ssize_t fh;
>  
>          pthread_mutex_lock(&lo->mutex);
> -        fh = lo_add_fd_mapping(req, fd);
> +        fh = lo_add_fd_mapping(lo, fd);
>          pthread_mutex_unlock(&lo->mutex);
>          if (fh == -1) {
>              close(fd);
> @@ -1892,38 +1924,25 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
>  
>  static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
>  {
> -    int fd;
> -    ssize_t fh;
> -    char buf[64];
>      struct lo_data *lo = lo_data(req);
> +    struct lo_inode *inode = lo_inode(req, ino);
> +    int err;
>  
>      fuse_log(FUSE_LOG_DEBUG, "lo_open(ino=%" PRIu64 ", flags=%d)\n", ino,
>               fi->flags);
>  
> -    update_open_flags(lo->writeback, lo->allow_direct_io, fi);
> -
> -    sprintf(buf, "%i", lo_fd(req, ino));
> -    fd = openat(lo->proc_self_fd, buf, fi->flags & ~O_NOFOLLOW);
> -    if (fd == -1) {
> -        return (void)fuse_reply_err(req, errno);
> -    }
> -
> -    pthread_mutex_lock(&lo->mutex);
> -    fh = lo_add_fd_mapping(req, fd);
> -    pthread_mutex_unlock(&lo->mutex);
> -    if (fh == -1) {
> -        close(fd);
> -        fuse_reply_err(req, ENOMEM);
> +    if (!inode) {
> +        fuse_reply_err(req, EBADF);
>          return;
>      }
>  
> -    fi->fh = fh;
> -    if (lo->cache == CACHE_NONE) {
> -        fi->direct_io = 1;
> -    } else if (lo->cache == CACHE_ALWAYS) {
> -        fi->keep_cache = 1;
> +    err = lo_do_open(lo, inode, fi);
> +    lo_inode_put(lo, &inode);
> +    if (err) {
> +        fuse_reply_err(req, err);
> +    } else {
> +        fuse_reply_open(req, fi);
>      }
> -    fuse_reply_open(req, fi);
>  }
>  
>  static void lo_release(fuse_req_t req, fuse_ino_t ino,