Blame SOURCES/kvm-virtiofsd-passthrough_ll-add-fd_map-to-hide-file-des.patch

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From 35337e604e9149d6d8fcf74b8b82ac33a8611ebb 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 19:01:16 +0100
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Subject: [PATCH 045/116] virtiofsd: passthrough_ll: add fd_map to hide file
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 descriptors
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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: <20200127190227.40942-42-dgilbert@redhat.com>
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Patchwork-id: 93494
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O-Subject: [RHEL-AV-8.2 qemu-kvm PATCH 041/112] virtiofsd: passthrough_ll: add fd_map to hide file descriptors
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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 file descriptor numbers to clients.  This prevents the
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abuse of internal file descriptors (like stdin/stdout).
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Fix from:
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Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
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dgilbert:
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  Added lseek
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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 73b4d19dfc4248a74c1f3e511cfa934681d9c602)
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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 | 116 +++++++++++++++++++++++++++++++--------
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 1 file changed, 94 insertions(+), 22 deletions(-)
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diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
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index 5f5a72f..9815bfa 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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@@ -60,6 +60,7 @@ struct lo_map_elem {
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     union {
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         struct lo_inode *inode;
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         struct lo_dirp *dirp;
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+        int fd;
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         ssize_t freelist;
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     };
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     bool in_use;
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@@ -107,6 +108,7 @@ struct lo_data {
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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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     struct lo_map dirp_map; /* protected by lo->mutex */
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+    struct lo_map fd_map; /* protected by lo->mutex */
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 };
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 static const struct fuse_opt lo_opts[] = {
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@@ -237,6 +239,20 @@ static void lo_map_remove(struct lo_map *map, size_t key)
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 }
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 /* Assumes lo->mutex is held */
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+static ssize_t lo_add_fd_mapping(fuse_req_t req, int fd)
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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)->fd_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->fd = fd;
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+    return elem - lo_data(req)->fd_map.elems;
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+}
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+
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+/* Assumes lo->mutex is held */
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 static ssize_t lo_add_dirp_mapping(fuse_req_t req, struct lo_dirp *dirp)
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 {
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     struct lo_map_elem *elem;
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@@ -350,6 +366,22 @@ static int utimensat_empty_nofollow(struct lo_inode *inode,
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     return utimensat(AT_FDCWD, procname, tv, 0);
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 }
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+static int lo_fi_fd(fuse_req_t req, struct fuse_file_info *fi)
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+{
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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->fd_map, fi->fh);
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+    pthread_mutex_unlock(&lo->mutex);
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+
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+    if (!elem) {
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+        return -1;
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+    }
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+
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+    return elem->fd;
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+}
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+
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 static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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                        int valid, struct fuse_file_info *fi)
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 {
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@@ -358,6 +390,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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     struct lo_inode *inode;
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     int ifd;
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     int res;
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+    int fd;
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     inode = lo_inode(req, ino);
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     if (!inode) {
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@@ -367,9 +400,14 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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     ifd = inode->fd;
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+    /* If fi->fh is invalid we'll report EBADF later */
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+    if (fi) {
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+        fd = lo_fi_fd(req, fi);
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+    }
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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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+            res = fchmod(fd, attr->st_mode);
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         } else {
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             sprintf(procname, "/proc/self/fd/%i", ifd);
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             res = chmod(procname, attr->st_mode);
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@@ -389,7 +427,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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     }
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     if (valid & FUSE_SET_ATTR_SIZE) {
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         if (fi) {
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-            res = ftruncate(fi->fh, attr->st_size);
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+            res = ftruncate(fd, attr->st_size);
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         } else {
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             sprintf(procname, "/proc/self/fd/%i", ifd);
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             res = truncate(procname, attr->st_size);
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@@ -419,7 +457,7 @@ static void lo_setattr(fuse_req_t req, fuse_ino_t ino, struct stat *attr,
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         }
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         if (fi) {
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-            res = futimens(fi->fh, tv);
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+            res = futimens(fd, tv);
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         } else {
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             res = utimensat_empty_nofollow(inode, tv);
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         }
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@@ -1096,7 +1134,18 @@ static void lo_create(fuse_req_t req, fuse_ino_t parent, const char *name,
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     lo_restore_cred(&old);
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     if (!err) {
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-        fi->fh = fd;
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+        ssize_t fh;
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+
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+        pthread_mutex_lock(&lo->mutex);
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+        fh = lo_add_fd_mapping(req, fd);
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+        pthread_mutex_unlock(&lo->mutex);
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+        if (fh == -1) {
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+            close(fd);
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+            fuse_reply_err(req, ENOMEM);
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+            return;
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+        }
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+
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+        fi->fh = fh;
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         err = lo_do_lookup(req, parent, name, &e);
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     }
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     if (lo->cache == CACHE_NEVER) {
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@@ -1140,6 +1189,7 @@ static void lo_fsyncdir(fuse_req_t req, fuse_ino_t ino, int datasync,
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 static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
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 {
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     int fd;
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+    ssize_t fh;
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     char buf[64];
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     struct lo_data *lo = lo_data(req);
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@@ -1175,7 +1225,16 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
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         return (void)fuse_reply_err(req, errno);
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     }
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-    fi->fh = fd;
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+    pthread_mutex_lock(&lo->mutex);
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+    fh = lo_add_fd_mapping(req, fd);
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+    pthread_mutex_unlock(&lo->mutex);
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+    if (fh == -1) {
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+        close(fd);
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+        fuse_reply_err(req, ENOMEM);
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+        return;
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+    }
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+
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+    fi->fh = fh;
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     if (lo->cache == CACHE_NEVER) {
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         fi->direct_io = 1;
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     } else if (lo->cache == CACHE_ALWAYS) {
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@@ -1187,9 +1246,18 @@ static void lo_open(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
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 static void lo_release(fuse_req_t req, fuse_ino_t ino,
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                        struct fuse_file_info *fi)
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 {
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+    struct lo_data *lo = lo_data(req);
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+    int fd;
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+
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     (void)ino;
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-    close(fi->fh);
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+    fd = lo_fi_fd(req, fi);
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+
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+    pthread_mutex_lock(&lo->mutex);
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+    lo_map_remove(&lo->fd_map, fi->fh);
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+    pthread_mutex_unlock(&lo->mutex);
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+
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+    close(fd);
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     fuse_reply_err(req, 0);
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 }
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@@ -1197,7 +1265,7 @@ static void lo_flush(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi)
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 {
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     int res;
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     (void)ino;
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-    res = close(dup(fi->fh));
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+    res = close(dup(lo_fi_fd(req, fi)));
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     fuse_reply_err(req, res == -1 ? errno : 0);
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 }
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@@ -1224,7 +1292,7 @@ static void lo_fsync(fuse_req_t req, fuse_ino_t ino, int datasync,
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             return (void)fuse_reply_err(req, errno);
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         }
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     } else {
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-        fd = fi->fh;
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+        fd = lo_fi_fd(req, fi);
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     }
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     if (datasync) {
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@@ -1251,7 +1319,7 @@ static void lo_read(fuse_req_t req, fuse_ino_t ino, size_t size, off_t offset,
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     }
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     buf.buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
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-    buf.buf[0].fd = fi->fh;
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+    buf.buf[0].fd = lo_fi_fd(req, fi);
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     buf.buf[0].pos = offset;
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     fuse_reply_data(req, &buf);
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@@ -1266,7 +1334,7 @@ static void lo_write_buf(fuse_req_t req, fuse_ino_t ino,
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     struct fuse_bufvec out_buf = FUSE_BUFVEC_INIT(fuse_buf_size(in_buf));
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     out_buf.buf[0].flags = FUSE_BUF_IS_FD | FUSE_BUF_FD_SEEK;
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-    out_buf.buf[0].fd = fi->fh;
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+    out_buf.buf[0].fd = lo_fi_fd(req, fi);
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     out_buf.buf[0].pos = off;
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     if (lo_debug(req)) {
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@@ -1303,7 +1371,7 @@ static void lo_fallocate(fuse_req_t req, fuse_ino_t ino, int mode, off_t offset,
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     (void)ino;
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 #ifdef CONFIG_FALLOCATE
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-    err = fallocate(fi->fh, mode, offset, length);
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+    err = fallocate(lo_fi_fd(req, fi), mode, offset, length);
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     if (err < 0) {
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         err = errno;
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     }
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@@ -1314,7 +1382,7 @@ static void lo_fallocate(fuse_req_t req, fuse_ino_t ino, int mode, off_t offset,
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         return;
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     }
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-    err = posix_fallocate(fi->fh, offset, length);
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+    err = posix_fallocate(lo_fi_fd(req, fi), offset, length);
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 #endif
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     fuse_reply_err(req, err);
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@@ -1326,7 +1394,7 @@ static void lo_flock(fuse_req_t req, fuse_ino_t ino, struct fuse_file_info *fi,
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     int res;
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     (void)ino;
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-    res = flock(fi->fh, op);
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+    res = flock(lo_fi_fd(req, fi), op);
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     fuse_reply_err(req, res == -1 ? errno : 0);
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 }
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@@ -1551,17 +1619,19 @@ static void lo_copy_file_range(fuse_req_t req, fuse_ino_t ino_in, off_t off_in,
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                                off_t off_out, struct fuse_file_info *fi_out,
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                                size_t len, int flags)
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 {
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+    int in_fd, out_fd;
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     ssize_t res;
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-    if (lo_debug(req))
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-        fuse_log(FUSE_LOG_DEBUG,
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-                 "lo_copy_file_range(ino=%" PRIu64 "/fd=%lu, "
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-                 "off=%lu, ino=%" PRIu64 "/fd=%lu, "
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-                 "off=%lu, size=%zd, flags=0x%x)\n",
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-                 ino_in, fi_in->fh, off_in, ino_out, fi_out->fh, off_out, len,
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-                 flags);
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+    in_fd = lo_fi_fd(req, fi_in);
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+    out_fd = lo_fi_fd(req, fi_out);
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+
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+    fuse_log(FUSE_LOG_DEBUG,
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+             "lo_copy_file_range(ino=%" PRIu64 "/fd=%d, "
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+             "off=%lu, ino=%" PRIu64 "/fd=%d, "
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+             "off=%lu, size=%zd, flags=0x%x)\n",
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+             ino_in, in_fd, off_in, ino_out, out_fd, off_out, len, flags);
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-    res = copy_file_range(fi_in->fh, &off_in, fi_out->fh, &off_out, len, flags);
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+    res = copy_file_range(in_fd, &off_in, out_fd, &off_out, len, flags);
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     if (res < 0) {
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         fuse_reply_err(req, -errno);
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     } else {
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@@ -1576,7 +1646,7 @@ static void lo_lseek(fuse_req_t req, fuse_ino_t ino, off_t off, int whence,
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     off_t res;
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     (void)ino;
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-    res = lseek(fi->fh, off, whence);
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+    res = lseek(lo_fi_fd(req, fi), off, whence);
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     if (res != -1) {
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         fuse_reply_lseek(req, res);
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     } else {
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@@ -1661,6 +1731,7 @@ int main(int argc, char *argv[])
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     root_elem->inode = &lo.root;
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     lo_map_init(&lo.dirp_map);
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+    lo_map_init(&lo.fd_map);
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     if (fuse_parse_cmdline(&args, &opts) != 0) {
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         return 1;
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@@ -1758,6 +1829,7 @@ 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.fd_map);
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     lo_map_destroy(&lo.dirp_map);
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     lo_map_destroy(&lo.ino_map);
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-- 
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1.8.3.1
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