vfs_ceph_new: switch to ceph_readdir_r

Prefer a safe version of ceph_readdir, where the directory entry struct
is allocated by the caller. Use a dynamic-allocated 'struct dirent'
which is associated with a directory vfs_ceph_fh (optional), which is
allocated on-the-fly upon start of READDIR and released at the end or
CLOSEDIR (or unlikely readdir error).

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15703

Signed-off-by: Shachar Sharon <ssharon@redhat.com>
Reviewed-by: John Mulligan <jmulligan@redhat.com>
Reviewed-by: Anoop C S <anoopcs@samba.org>
Autobuild-User(master): Anoop C S <anoopcs@samba.org>
Autobuild-Date(master): Fri Oct 25 10:29:44 UTC 2024 on atb-devel-224

(cherry picked from commit ce459ddbcd0f32252858a7640f6871057eb14645)

diff --git a/source3/modules/vfs_ceph_new.c b/source3/modules/vfs_ceph_new.c
index c7a7c2d3ab64b5d3e8efbe78d49324b58d11f17b..e5517a98298a265fd3a9b69115b11774430fe9aa 100644 (file)
--- a/source3/modules/vfs_ceph_new.c
+++ b/source3/modules/vfs_ceph_new.c
@@ -157,6 +157,7 @@ struct vfs_ceph_config {
        CEPH_FN(ceph_version);
        CEPH_FN(ceph_readdir);
        CEPH_FN(ceph_rewinddir);
+       CEPH_FN(ceph_readdir_r);
 };
 
 /*
@@ -405,6 +406,7 @@ static bool vfs_cephfs_load_lib(struct vfs_ceph_config *config)
        CHECK_CEPH_FN(libhandle, ceph_version);
        CHECK_CEPH_FN(libhandle, ceph_readdir);
        CHECK_CEPH_FN(libhandle, ceph_rewinddir);
+       CHECK_CEPH_FN(libhandle, ceph_readdir_r);
 
        config->libhandle = libhandle;
 
@@ -625,6 +627,7 @@ struct vfs_ceph_fh {
        struct vfs_ceph_config *config;
        struct vfs_ceph_iref iref;
        struct Fh *fh;
+       struct dirent *de;
        int fd;
 };
 
@@ -642,6 +645,22 @@ static int cephmount_next_fd(struct cephmount_cached *cme)
        return (int)next;
 }
 
+static struct dirent *vfs_ceph_get_fh_dirent(struct vfs_ceph_fh *cfh)
+{
+       if (cfh->de == NULL) {
+               cfh->de = talloc_zero_size(cfh->fsp, sizeof(*(cfh->de)));
+       }
+       return cfh->de;
+}
+
+static void vfs_ceph_put_fh_dirent(struct vfs_ceph_fh *cfh)
+{
+       if (cfh->de != NULL) {
+               TALLOC_FREE(cfh->de);
+               cfh->de = NULL;
+       }
+}
+
 static int vfs_ceph_release_fh(struct vfs_ceph_fh *cfh)
 {
        int ret = 0;
@@ -661,6 +680,7 @@ static int vfs_ceph_release_fh(struct vfs_ceph_fh *cfh)
                vfs_ceph_userperm_del(cfh->config, cfh->uperm);
                cfh->uperm = NULL;
        }
+       vfs_ceph_put_fh_dirent(cfh);
        cfh->fd = -1;
 
        return ret;
@@ -1167,18 +1187,20 @@ static int vfs_ceph_ll_opendir(const struct vfs_handle_struct *handle,
                                          cfh->uperm);
 }
 
-static struct dirent *vfs_ceph_ll_readdir(const struct vfs_handle_struct *hndl,
-                                         const struct vfs_ceph_fh *dircfh)
+static int vfs_ceph_ll_readdir(const struct vfs_handle_struct *hndl,
+                              const struct vfs_ceph_fh *dircfh)
 {
        struct vfs_ceph_config *config = NULL;
 
        SMB_VFS_HANDLE_GET_DATA(hndl, config, struct vfs_ceph_config,
-                               return NULL);
+                               return -ENOMEM);
 
        DBG_DEBUG("[ceph] ceph_readdir: ino=%" PRIu64 " fd=%d\n",
                  dircfh->iref.ino, dircfh->fd);
 
-       return config->ceph_readdir_fn(config->mount, dircfh->dirp.cdr);
+       return config->ceph_readdir_r_fn(config->mount,
+                                        dircfh->dirp.cdr,
+                                        dircfh->de);
 }
 
 static void vfs_ceph_ll_rewinddir(const struct vfs_handle_struct *handle,
@@ -1959,21 +1981,35 @@ static struct dirent *vfs_ceph_readdir(struct vfs_handle_struct *handle,
                                       struct files_struct *dirfsp,
                                       DIR *dirp)
 {
-       const struct vfs_ceph_fh *dircfh = (const struct vfs_ceph_fh *)dirp;
+       struct vfs_ceph_fh *dircfh = (struct vfs_ceph_fh *)dirp;
        struct dirent *result = NULL;
        int saved_errno = errno;
+       int ret = -1;
 
        DBG_DEBUG("[CEPH] readdir(%p, %p)\n", handle, dirp);
 
-       errno = 0;
-       result = vfs_ceph_ll_readdir(handle, dircfh);
-       if ((result == NULL) && (errno != 0)) {
-               saved_errno = errno;
-               DBG_DEBUG("[CEPH] readdir(...) = %d\n", errno);
+       result = vfs_ceph_get_fh_dirent(dircfh);
+       if (result == NULL) {
+               /* Memory allocation failure */
+               return NULL;
+       }
+
+       /* The low-level call uses 'dircfh->de' which is now 'result' */
+       ret = vfs_ceph_ll_readdir(handle, dircfh);
+       if (ret < 0) {
+               /* Error case */
+               DBG_DEBUG("[CEPH] readdir(...) = %d\n", ret);
+               vfs_ceph_put_fh_dirent(dircfh);
+               result = NULL;
+               saved_errno = ret;
+       } else if (ret == 0) {
+               /* End of directory stream */
+               vfs_ceph_put_fh_dirent(dircfh);
+               result = NULL;
        } else {
+               /* Normal case */
                DBG_DEBUG("[CEPH] readdir(...) = %p\n", result);
        }
-
        errno = saved_errno;
        return result;
 }