storage/posix: handle dentries from different mount points in readdir

- If posix translator is configured to have export directories to span accross
    different mount points, inode number is transformed in the dentry returned.
    Otherwise, the entry is not added to list of entries returned in readdir
    callback.
  - storage/posix returns ENOENT if the file is on different mount point other
    than that of exported directory and is not configured for export directory
    spanning across multiple mountpoints during lookup. But, since stat-prefetch
    shortcuts lookup calls, its necessary that readdir return only valid
    dentries.

Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 221 (stat prefetch implementation)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=221

1 files changed, 51 insertions, 34 deletions

diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index b124d1362..4eb484bc0 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -3502,26 +3502,25 @@ int32_t
 posix_readdir (call_frame_t *frame, xlator_t *this,
                fd_t *fd, size_t size, off_t off)
 {
-	uint64_t          tmp_pfd = 0;
-        struct posix_fd * pfd    = NULL;
-        DIR *             dir    = NULL;
-        int               ret    = -1;
-        size_t            filled = 0;
-	int               count = 0;
-
-        int32_t           op_ret   = -1;
-        int32_t           op_errno = 0;
-
-        gf_dirent_t *     this_entry = NULL;
-	gf_dirent_t       entries;
-        struct dirent *   entry      = NULL;
-        off_t             in_case    = -1;
-        int32_t           this_size  = -1;
-
-        char *            real_path      = NULL;
-        int               real_path_len  = -1;
-        char *            entry_path     = NULL;
-        int               entry_path_len = -1;
+	uint64_t              tmp_pfd        = 0;
+        struct posix_fd      *pfd            = NULL;
+        DIR                  *dir            = NULL;
+        int                   ret            = -1;
+        size_t                filled         = 0;
+	int                   count          = 0;
+        int32_t               op_ret         = -1;
+        int32_t               op_errno       = 0;
+        gf_dirent_t          *this_entry     = NULL;
+	gf_dirent_t           entries;
+        struct dirent        *entry          = NULL;
+        off_t                 in_case        = -1;
+        int32_t               this_size      = -1;
+        char                 *real_path      = NULL;
+        int                   real_path_len  = -1;
+        char                 *entry_path     = NULL;
+        int                   entry_path_len = -1;
+        struct posix_private *priv           = NULL;
+        struct stat           stbuf          = {0, };
 
         VALIDATE_OR_GOTO (frame, out);
         VALIDATE_OR_GOTO (this, out);
@@ -3529,6 +3528,8 @@ posix_readdir (call_frame_t *frame, xlator_t *this,
 
 	INIT_LIST_HEAD (&entries.list);
 
+        priv = this->private;
+
         ret = fd_ctx_get (fd, this, &tmp_pfd);
         if (ret < 0) {
                 gf_log (this->name, GF_LOG_DEBUG,
@@ -3609,25 +3610,41 @@ posix_readdir (call_frame_t *frame, xlator_t *this,
                         break;
                 }
 
+                strcpy (entry_path + real_path_len + 1, entry->d_name);
+                lstat (entry_path, &stbuf);
+                /* Make sure we don't access another mountpoint inside export dir.
+                 * It may cause inode number to repeat from single export point,
+                 * which leads to severe problems..
+                 */
+                if (!priv->span_devices) {
+                        if (priv->st_device[0] != stbuf.st_dev) {
+                                continue;
+                        }
+                } else {
+                        op_ret = posix_scale_st_ino (priv, &stbuf);
+                        if (-1 == op_ret) {
+                                continue;
+                        }
+                }
+
+                entry->d_ino = stbuf.st_ino;
 
-		this_entry = gf_dirent_for_name (entry->d_name);
+                this_entry = gf_dirent_for_name (entry->d_name);
 
-		if (!this_entry) {
-			gf_log (this->name, GF_LOG_ERROR,
-				"could not create gf_dirent for entry %s: (%s)",
-				entry->d_name, strerror (errno));
-			goto out;
-		}
-		this_entry->d_off = telldir (dir);
-		this_entry->d_ino = entry->d_ino;
+                if (!this_entry) {
+                        gf_log (this->name, GF_LOG_ERROR,
+                                "could not create gf_dirent for entry %s: (%s)",
+                                entry->d_name, strerror (errno));
+                        goto out;
+                }
+                this_entry->d_off = telldir (dir);
+                this_entry->d_ino = entry->d_ino;
+                this_entry->d_stat = stbuf;
 
-		list_add_tail (&this_entry->list, &entries.list);
+                list_add_tail (&this_entry->list, &entries.list);
 
                 filled += this_size;
-		count ++;
-
-                strcpy (entry_path + real_path_len + 1, this_entry->d_name);
-                lstat (entry_path, &this_entry->d_stat);
+                count ++;
         }
 
         op_ret = count;