lustre/liblustre/dir.c

   1 /*
   2  * GPL HEADER START
   3  *
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 only,
   8  * as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License version 2 for more details (a copy is included
  14  * in the LICENSE file that accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * version 2 along with this program; If not, see
  18  * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
  19  *
  20  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  21  * CA 95054 USA or visit www.sun.com if you need additional information or
  22  * have any questions.
  23  *
  24  * GPL HEADER END
  25  */
  26 /*
  27  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  28  * Use is subject to license terms.
  29  *
  30  * Copyright (c) 2011, 2012, Intel Corporation.
  31  */
  32 /*
  33  * This file is part of Lustre, http://www.lustre.org/
  34  * Lustre is a trademark of Sun Microsystems, Inc.
  35  *
  36  * lustre/liblustre/dir.c
  37  *
  38  * Lustre Light directory handling
  39  */
  40
  41 #define DEBUG_SUBSYSTEM S_LLITE
  42
  43 #include <errno.h>
  44 #include <stddef.h>
  45 #include <string.h>
  46 #include <sys/stat.h>
  47 #include <sys/types.h>
  48 #include <libcfs/libcfs.h>
  49 #include <lustre/lustre_idl.h>
  50 #include <liblustre.h>
  51 #include <lclient.h>
  52 #include <lustre_dlm.h>
  53 #include <lustre_lite.h>
  54 #include <lustre_net.h>
  55 #include <lustre_req_layout.h>
  56 #include <obd.h>
  57 #include <obd_class.h>
  58 #include <obd_support.h>
  59 #include "llite_lib.h"
  60 #include <dirent.h>
  61
  62 /* (new) readdir implementation overview can be found in lustre/llite/dir.c */
  63 static int llu_dir_do_readpage(struct inode *inode, struct page *page)
  64 {
  65         struct llu_inode_info *lli = llu_i2info(inode);
  66         struct intnl_stat     *st = llu_i2stat(inode);
  67         struct llu_sb_info    *sbi = llu_i2sbi(inode);
  68         struct ptlrpc_request *request;
  69         struct lustre_handle   lockh;
  70         struct mdt_body       *body;
  71         struct lookup_intent   it = { .it_op = IT_READDIR };
  72         struct md_op_data      op_data = {{ 0 }};
  73         ldlm_policy_data_t policy = { .l_inodebits = { MDS_INODELOCK_UPDATE } };
  74         int rc = 0;
  75         ENTRY;
  76
  77         llu_prep_md_op_data(&op_data, inode, NULL, NULL, 0, 0, LUSTRE_OPC_ANY);
  78         rc = md_lock_match(sbi->ll_md_exp, LDLM_FL_BLOCK_GRANTED,
  79                            &lli->lli_fid, LDLM_IBITS, &policy, LCK_CR, &lockh);
  80         if (!rc) {
  81                 struct ldlm_enqueue_info einfo = {
  82                         .ei_type        = LDLM_IBITS,
  83                         .ei_mode        = LCK_CR,
  84                         .ei_cb_bl       = llu_md_blocking_ast,
  85                         .ei_cb_cp       = ldlm_completion_ast,
  86                         .ei_cbdata      = inode,
  87                 };
  88
  89                 rc = md_enqueue(sbi->ll_md_exp, &einfo, &it,
  90                                 &op_data, &lockh, NULL, 0, NULL,
  91                                 LDLM_FL_CANCEL_ON_BLOCK);
  92                 request = (struct ptlrpc_request *)it.d.lustre.it_data;
  93                 if (request)
  94                         ptlrpc_req_finished(request);
  95                 if (rc < 0) {
  96                         CERROR("lock enqueue: err: %d\n", rc);
  97                         RETURN(rc);
  98                 }
  99         }
 100         ldlm_lock_dump_handle(D_OTHER, &lockh);
 101
 102         op_data.op_hash_offset = hash_x_index(page->index, 0);
 103         op_data.op_npages = 1;
 104         rc = md_readpage(sbi->ll_md_exp, &op_data, &page, &request);
 105         if (!rc) {
 106                 body = req_capsule_server_get(&request->rq_pill, &RMF_MDT_BODY);
 107                 LASSERT(body != NULL);         /* checked by md_readpage() */
 108
 109                 if (body->valid & OBD_MD_FLSIZE)
 110                         st->st_size = body->size;
 111         } else {
 112                 CERROR("read_dir_page(%ld) error %d\n", page->index, rc);
 113         }
 114         ptlrpc_req_finished(request);
 115         EXIT;
 116
 117         ldlm_lock_decref(&lockh, LCK_CR);
 118         return rc;
 119 }
 120
 121 static struct page *llu_dir_read_page(struct inode *ino, __u64 hash,
 122                                      int exact, struct ll_dir_chain *chain)
 123 {
 124         struct page *page;
 125         int rc;
 126         ENTRY;
 127
 128         OBD_PAGE_ALLOC(page, 0);
 129         if (!page)
 130                 RETURN(ERR_PTR(-ENOMEM));
 131         page->index = hash_x_index(hash, 0);
 132
 133         rc = llu_dir_do_readpage(ino, page);
 134         if (rc) {
 135                 OBD_PAGE_FREE(page);
 136                 RETURN(ERR_PTR(rc));
 137         }
 138
 139         return page;
 140 }
 141
 142 static void *(*memmover)(void *, const void *, size_t) = memmove;
 143
 144 #define NAME_OFFSET(de) ((int) ((de)->d_name - (char *) (de)))
 145 #define ROUND_UP64(x)   (((x)+sizeof(__u64)-1) & ~(sizeof(__u64)-1))
 146 static int filldir(char *buf, int buflen, const char *name, int namelen,
 147                    loff_t offset, ino_t ino, unsigned int d_type, int *filled)
 148 {
 149         struct dirent64 *dirent = (struct dirent64 *)(buf + *filled);
 150         struct dirent64  holder;
 151         int reclen = ROUND_UP64(NAME_OFFSET(dirent) + namelen + 1);
 152
 153         /*
 154          * @buf is not guaranteed to be properly aligned. To work around,
 155          * first fill stack-allocated @holder, then copy @holder into @buf by
 156          * memmove().
 157          */
 158
 159         /* check overflow */
 160         if ((*filled + reclen) > buflen)
 161                 return 1;
 162
 163         holder.d_ino = ino;
 164 #ifdef _DIRENT_HAVE_D_OFF
 165         holder.d_off = offset;
 166 #endif
 167         holder.d_reclen = reclen;
 168 #ifdef _DIRENT_HAVE_D_TYPE
 169         holder.d_type = (unsigned short) d_type;
 170 #endif
 171         /* gcc unrolls memcpy() of structs into field-wise assignments,
 172          * assuming proper alignment. Humor it. */
 173         (*memmover)(dirent, &holder, NAME_OFFSET(dirent));
 174         memcpy(dirent->d_name, name, namelen);
 175         dirent->d_name[namelen] = 0;
 176
 177         *filled += reclen;
 178
 179         return 0;
 180 }
 181
 182 /*
 183  * TODO: much of the code here is similar/identical to llite ll_readdir().
 184  * These code can be factored out and shared in a common module.
 185  */
 186
 187 ssize_t llu_iop_filldirentries(struct inode *dir, _SYSIO_OFF_T *basep,
 188                                char *buf, size_t nbytes)
 189 {
 190         struct llu_inode_info *lli = llu_i2info(dir);
 191         struct intnl_stat     *st = llu_i2stat(dir);
 192         loff_t                 pos = *basep;
 193         struct ll_dir_chain    chain;
 194         struct page            *page;
 195         int filled = 0;
 196         int rc;
 197         int done;
 198         __u16 type;
 199         ENTRY;
 200
 201         liblustre_wait_event(0);
 202
 203         if (st->st_size == 0) {
 204                 CWARN("dir size is 0?\n");
 205                 RETURN(0);
 206         }
 207
 208         if (pos == MDS_DIR_END_OFF)
 209                 /*
 210                  * end-of-file.
 211                  */
 212                 RETURN(0);
 213
 214         rc    = 0;
 215         done  = 0;
 216         ll_dir_chain_init(&chain);
 217
 218         page = llu_dir_read_page(dir, pos, 0, &chain);
 219         while (rc == 0 && !done) {
 220                 struct lu_dirpage *dp;
 221                 struct lu_dirent  *ent;
 222
 223                 if (!IS_ERR(page)) {
 224                         /*
 225                          * If page is empty (end of directoryis reached),
 226                          * use this value.
 227                          */
 228                         __u64 hash = MDS_DIR_END_OFF;
 229                         __u64 next;
 230
 231                         dp = page->addr;
 232                         for (ent = lu_dirent_start(dp); ent != NULL && !done;
 233                              ent = lu_dirent_next(ent)) {
 234                                 char          *name;
 235                                 int            namelen;
 236                                 struct lu_fid  fid;
 237                                 __u64          ino;
 238
 239                                 hash    = le64_to_cpu(ent->lde_hash);
 240                                 namelen = le16_to_cpu(ent->lde_namelen);
 241
 242                                 if (hash < pos)
 243                                         /*
 244                                          * Skip until we find target hash
 245                                          * value.
 246                                          */
 247                                         continue;
 248
 249                                 if (namelen == 0)
 250                                         /*
 251                                          * Skip dummy record.
 252                                          */
 253                                         continue;
 254
 255                                 fid  = ent->lde_fid;
 256                                 name = ent->lde_name;
 257                                 fid_le_to_cpu(&fid, &fid);
 258                                 ino  = cl_fid_build_ino(&fid, 0);
 259                                 type = ll_dirent_type_get(ent);
 260                                 done = filldir(buf, nbytes, name, namelen,
 261                                                (loff_t)hash, ino, type,
 262                                                &filled);
 263                         }
 264                         next = le64_to_cpu(dp->ldp_hash_end);
 265                         OBD_PAGE_FREE(page);
 266                         if (!done) {
 267                                 pos = next;
 268                                 if (pos == MDS_DIR_END_OFF)
 269                                         /*
 270                                          * End of directory reached.
 271                                          */
 272                                         done = 1;
 273                                 else if (1 /* chain is exhausted*/)
 274                                         /*
 275                                          * Normal case: continue to the next
 276                                          * page.
 277                                          */
 278                                         page = llu_dir_read_page(dir, pos, 1,
 279                                                                &chain);
 280                                 else {
 281                                         /*
 282                                          * go into overflow page.
 283                                          */
 284                                 }
 285                         } else {
 286                                 pos = hash;
 287                                 if (filled == 0)
 288                                         GOTO(out, filled = -EINVAL);
 289                         }
 290                 } else {
 291                         rc = PTR_ERR(page);
 292                         CERROR("error reading dir "DFID" at %lu: rc %d\n",
 293                                PFID(&lli->lli_fid), (unsigned long)pos, rc);
 294                 }
 295         }
 296         lli->lli_dir_pos = (loff_t)pos;
 297         *basep = lli->lli_dir_pos;
 298 out:
 299         ll_dir_chain_fini(&chain);
 300         liblustre_wait_event(0);
 301         RETURN(filled);
 302 }