1 files changed, 117 insertions, 98 deletions

diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 770d5a9781c1..69d2c826a23b 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -111,6 +111,14 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
                         return;
         }
 
+        /*
+         * If we know that the inode will need to be revalidated immediately,
+         * then don't create a new dentry for it. We'll end up doing an on
+         * the wire call either way and this spares us an invalidation.
+         */
+        if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
+                return;
+
         dentry = d_alloc(parent, name);
         if (!dentry)
                 return;
@@ -126,6 +134,22 @@ out:
         dput(dentry);
 }
 
+/*
+ * Is it possible that this directory might turn out to be a DFS referral
+ * once we go to try and use it?
+ */
+static bool
+cifs_dfs_is_possible(struct cifs_sb_info *cifs_sb)
+{
+#ifdef CONFIG_CIFS_DFS_UPCALL
+        struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb);
+
+        if (tcon->Flags & SMB_SHARE_IS_IN_DFS)
+                return true;
+#endif
+        return false;
+}
+
 static void
 cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
 {
@@ -135,6 +159,19 @@ cifs_fill_common_info(struct cifs_fattr *fattr, struct cifs_sb_info *cifs_sb)
         if (fattr->cf_cifsattrs & ATTR_DIRECTORY) {
                 fattr->cf_mode = S_IFDIR | cifs_sb->mnt_dir_mode;
                 fattr->cf_dtype = DT_DIR;
+                /*
+                 * Windows CIFS servers generally make DFS referrals look
+                 * like directories in FIND_* responses with the reparse
+                 * attribute flag also set (since DFS junctions are
+                 * reparse points). We must revalidate at least these
+                 * directory inodes before trying to use them (if
+                 * they are DFS we will get PATH_NOT_COVERED back
+                 * when queried directly and can then try to connect
+                 * to the DFS target)
+                 */
+                if (cifs_dfs_is_possible(cifs_sb) &&
+                    (fattr->cf_cifsattrs & ATTR_REPARSE))
+                        fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
         } else {
                 fattr->cf_mode = S_IFREG | cifs_sb->mnt_file_mode;
                 fattr->cf_dtype = DT_REG;
@@ -537,14 +574,14 @@ static int cifs_save_resume_key(const char *current_entry,
  * every entry (do not increment for . or .. entry).
  */
 static int
-find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon,
+find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon, loff_t pos,
                 struct file *file, char **current_entry, int *num_to_ret)
 {
         __u16 search_flags;
         int rc = 0;
         int pos_in_buf = 0;
         loff_t first_entry_in_buffer;
-        loff_t index_to_find = file->f_pos;
+        loff_t index_to_find = pos;
         struct cifsFileInfo *cfile = file->private_data;
         struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
         struct TCP_Server_Info *server = tcon->ses->server;
@@ -659,8 +696,9 @@ find_cifs_entry(const unsigned int xid, struct cifs_tcon *tcon,
         return rc;
 }
 
-static int cifs_filldir(char *find_entry, struct file *file, filldir_t filldir,
-                void *dirent, char *scratch_buf, unsigned int max_len)
+static int cifs_filldir(char *find_entry, struct file *file,
+                struct dir_context *ctx,
+                char *scratch_buf, unsigned int max_len)
 {
         struct cifsFileInfo *file_info = file->private_data;
         struct super_block *sb = file->f_path.dentry->d_sb;
@@ -740,13 +778,11 @@ static int cifs_filldir(char *find_entry, struct file *file, filldir_t filldir,
         cifs_prime_dcache(file->f_dentry, &name, &fattr);
 
         ino = cifs_uniqueid_to_ino_t(fattr.cf_uniqueid);
-        rc = filldir(dirent, name.name, name.len, file->f_pos, ino,
-                     fattr.cf_dtype);
-        return rc;
+        return !dir_emit(ctx, name.name, name.len, ino, fattr.cf_dtype);
 }
 
 
-int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
+int cifs_readdir(struct file *file, struct dir_context *ctx)
 {
         int rc = 0;
         unsigned int xid;
@@ -772,103 +808,86 @@ int cifs_readdir(struct file *file, void *direntry, filldir_t filldir)
                         goto rddir2_exit;
         }
 
-        switch ((int) file->f_pos) {
-        case 0:
-                if (filldir(direntry, ".", 1, file->f_pos,
-                     file_inode(file)->i_ino, DT_DIR) < 0) {
-                        cifs_dbg(VFS, "Filldir for current dir failed\n");
-                        rc = -ENOMEM;
-                        break;
-                }
-                file->f_pos++;
-        case 1:
-                if (filldir(direntry, "..", 2, file->f_pos,
-                     parent_ino(file->f_path.dentry), DT_DIR) < 0) {
-                        cifs_dbg(VFS, "Filldir for parent dir failed\n");
-                        rc = -ENOMEM;
-                        break;
-                }
-                file->f_pos++;
-        default:
-                /* 1) If search is active,
-                        is in current search buffer?
-                        if it before then restart search
-                        if after then keep searching till find it */
-
-                if (file->private_data == NULL) {
-                        rc = -EINVAL;
-                        free_xid(xid);
-                        return rc;
-                }
-                cifsFile = file->private_data;
-                if (cifsFile->srch_inf.endOfSearch) {
-                        if (cifsFile->srch_inf.emptyDir) {
-                                cifs_dbg(FYI, "End of search, empty dir\n");
-                                rc = 0;
-                                break;
-                        }
-                } /* else {
-                        cifsFile->invalidHandle = true;
-                        tcon->ses->server->close(xid, tcon, &cifsFile->fid);
-                } */
+        if (!dir_emit_dots(file, ctx))
+                goto rddir2_exit;
 
-                tcon = tlink_tcon(cifsFile->tlink);
-                rc = find_cifs_entry(xid, tcon, file, &current_entry,
-                                     &num_to_fill);
-                if (rc) {
-                        cifs_dbg(FYI, "fce error %d\n", rc);
-                        goto rddir2_exit;
-                } else if (current_entry != NULL) {
-                        cifs_dbg(FYI, "entry %lld found\n", file->f_pos);
-                } else {
-                        cifs_dbg(FYI, "could not find entry\n");
+        /* 1) If search is active,
+                is in current search buffer?
+                if it before then restart search
+                if after then keep searching till find it */
+
+        if (file->private_data == NULL) {
+                rc = -EINVAL;
+                goto rddir2_exit;
+        }
+        cifsFile = file->private_data;
+        if (cifsFile->srch_inf.endOfSearch) {
+                if (cifsFile->srch_inf.emptyDir) {
+                        cifs_dbg(FYI, "End of search, empty dir\n");
+                        rc = 0;
                         goto rddir2_exit;
                 }
-                cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
-                         num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
-                max_len = tcon->ses->server->ops->calc_smb_size(
-                                cifsFile->srch_inf.ntwrk_buf_start);
-                end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
-
-                tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
-                if (tmp_buf == NULL) {
-                        rc = -ENOMEM;
+        } /* else {
+                cifsFile->invalidHandle = true;
+                tcon->ses->server->close(xid, tcon, &cifsFile->fid);
+        } */
+
+        tcon = tlink_tcon(cifsFile->tlink);
+        rc = find_cifs_entry(xid, tcon, ctx->pos, file, &current_entry,
+                             &num_to_fill);
+        if (rc) {
+                cifs_dbg(FYI, "fce error %d\n", rc);
+                goto rddir2_exit;
+        } else if (current_entry != NULL) {
+                cifs_dbg(FYI, "entry %lld found\n", ctx->pos);
+        } else {
+                cifs_dbg(FYI, "could not find entry\n");
+                goto rddir2_exit;
+        }
+        cifs_dbg(FYI, "loop through %d times filling dir for net buf %p\n",
+                 num_to_fill, cifsFile->srch_inf.ntwrk_buf_start);
+        max_len = tcon->ses->server->ops->calc_smb_size(
+                        cifsFile->srch_inf.ntwrk_buf_start);
+        end_of_smb = cifsFile->srch_inf.ntwrk_buf_start + max_len;
+
+        tmp_buf = kmalloc(UNICODE_NAME_MAX, GFP_KERNEL);
+        if (tmp_buf == NULL) {
+                rc = -ENOMEM;
+                goto rddir2_exit;
+        }
+
+        for (i = 0; i < num_to_fill; i++) {
+                if (current_entry == NULL) {
+                        /* evaluate whether this case is an error */
+                        cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
+                                 num_to_fill, i);
                         break;
                 }
-
-                for (i = 0; (i < num_to_fill) && (rc == 0); i++) {
-                        if (current_entry == NULL) {
-                                /* evaluate whether this case is an error */
-                                cifs_dbg(VFS, "past SMB end,  num to fill %d i %d\n",
-                                         num_to_fill, i);
-                                break;
-                        }
-                        /*
-                         * if buggy server returns . and .. late do we want to
-                         * check for that here?
-                         */
-                        rc = cifs_filldir(current_entry, file, filldir,
-                                          direntry, tmp_buf, max_len);
-                        if (rc == -EOVERFLOW) {
+                /*
+                 * if buggy server returns . and .. late do we want to
+                 * check for that here?
+                 */
+                rc = cifs_filldir(current_entry, file, ctx,
+                                  tmp_buf, max_len);
+                if (rc) {
+                        if (rc > 0)
                                 rc = 0;
-                                break;
-                        }
-
-                        file->f_pos++;
-                        if (file->f_pos ==
-                                cifsFile->srch_inf.index_of_last_entry) {
-                                cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
-                                         file->f_pos, tmp_buf);
-                                cifs_save_resume_key(current_entry, cifsFile);
-                                break;
-                        } else
-                                current_entry =
-                                        nxt_dir_entry(current_entry, end_of_smb,
-                                                cifsFile->srch_inf.info_level);
+                        break;
                 }
-                kfree(tmp_buf);
-                break;
-        } /* end switch */
+
+                ctx->pos++;
+                if (ctx->pos ==
+                        cifsFile->srch_inf.index_of_last_entry) {
+                        cifs_dbg(FYI, "last entry in buf at pos %lld %s\n",
+                                 ctx->pos, tmp_buf);
+                        cifs_save_resume_key(current_entry, cifsFile);
+                        break;
+                } else
+                        current_entry =
+                                nxt_dir_entry(current_entry, end_of_smb,
+                                        cifsFile->srch_inf.info_level);
+        }
+        kfree(tmp_buf);
 
 rddir2_exit:
         free_xid(xid);