1/* -*- mode: c; c-basic-offset: 8; -*-
2 * vim: noexpandtab sw=8 ts=8 sts=0:
3 *
4 * dir.c
5 *
6 * Creates, reads, walks and deletes directory-nodes
7 *
8 * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
9 *
10 *  Portions of this code from linux/fs/ext3/dir.c
11 *
12 *  Copyright (C) 1992, 1993, 1994, 1995
13 *  Remy Card (card@masi.ibp.fr)
14 *  Laboratoire MASI - Institut Blaise pascal
15 *  Universite Pierre et Marie Curie (Paris VI)
16 *
17 *   from
18 *
19 *   linux/fs/minix/dir.c
20 *
21 *   Copyright (C) 1991, 1992 Linux Torvalds
22 *
23 * This program is free software; you can redistribute it and/or
24 * modify it under the terms of the GNU General Public
25 * License as published by the Free Software Foundation; either
26 * version 2 of the License, or (at your option) any later version.
27 *
28 * This program is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
31 * General Public License for more details.
32 *
33 * You should have received a copy of the GNU General Public
34 * License along with this program; if not, write to the
35 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
36 * Boston, MA 021110-1307, USA.
37 */
38
39#include <linux/fs.h>
40#include <linux/types.h>
41#include <linux/slab.h>
42#include <linux/highmem.h>
43
44#define MLOG_MASK_PREFIX ML_NAMEI
45#include <cluster/masklog.h>
46
47#include "ocfs2.h"
48
49#include "alloc.h"
50#include "dir.h"
51#include "dlmglue.h"
52#include "extent_map.h"
53#include "file.h"
54#include "inode.h"
55#include "journal.h"
56#include "namei.h"
57#include "suballoc.h"
58#include "uptodate.h"
59
60#include "buffer_head_io.h"
61
62static unsigned char ocfs2_filetype_table[] = {
63	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
64};
65
66static int ocfs2_extend_dir(struct ocfs2_super *osb,
67			    struct inode *dir,
68			    struct buffer_head *parent_fe_bh,
69			    struct buffer_head **new_de_bh);
70/*
71 * ocfs2_readdir()
72 *
73 */
74int ocfs2_readdir(struct file * filp, void * dirent, filldir_t filldir)
75{
76	int error = 0;
77	unsigned long offset, blk, last_ra_blk = 0;
78	int i, stored;
79	struct buffer_head * bh, * tmp;
80	struct ocfs2_dir_entry * de;
81	int err;
82	struct inode *inode = filp->f_path.dentry->d_inode;
83	struct super_block * sb = inode->i_sb;
84	unsigned int ra_sectors = 16;
85	int lock_level = 0;
86
87	mlog_entry("dirino=%llu\n",
88		   (unsigned long long)OCFS2_I(inode)->ip_blkno);
89
90	stored = 0;
91	bh = NULL;
92
93	error = ocfs2_meta_lock_atime(inode, filp->f_vfsmnt, &lock_level);
94	if (lock_level && error >= 0) {
95		/* We release EX lock which used to update atime
96		 * and get PR lock again to reduce contention
97		 * on commonly accessed directories. */
98		ocfs2_meta_unlock(inode, 1);
99		lock_level = 0;
100		error = ocfs2_meta_lock(inode, NULL, 0);
101	}
102	if (error < 0) {
103		if (error != -ENOENT)
104			mlog_errno(error);
105		/* we haven't got any yet, so propagate the error. */
106		stored = error;
107		goto bail_nolock;
108	}
109
110	offset = filp->f_pos & (sb->s_blocksize - 1);
111
112	while (!error && !stored && filp->f_pos < i_size_read(inode)) {
113		blk = (filp->f_pos) >> sb->s_blocksize_bits;
114		bh = ocfs2_bread(inode, blk, &err, 0);
115		if (!bh) {
116			mlog(ML_ERROR,
117			     "directory #%llu contains a hole at offset %lld\n",
118			     (unsigned long long)OCFS2_I(inode)->ip_blkno,
119			     filp->f_pos);
120			filp->f_pos += sb->s_blocksize - offset;
121			continue;
122		}
123
124		/* The idea here is to begin with 8k read-ahead and to stay
125		 * 4k ahead of our current position.
126		 *
127		 * TODO: Use the pagecache for this. We just need to
128		 * make sure it's cluster-safe... */
129		if (!last_ra_blk
130		    || (((last_ra_blk - blk) << 9) <= (ra_sectors / 2))) {
131			for (i = ra_sectors >> (sb->s_blocksize_bits - 9);
132			     i > 0; i--) {
133				tmp = ocfs2_bread(inode, ++blk, &err, 1);
134				if (tmp)
135					brelse(tmp);
136			}
137			last_ra_blk = blk;
138			ra_sectors = 8;
139		}
140
141revalidate:
142		/* If the dir block has changed since the last call to
143		 * readdir(2), then we might be pointing to an invalid
144		 * dirent right now.  Scan from the start of the block
145		 * to make sure. */
146		if (filp->f_version != inode->i_version) {
147			for (i = 0; i < sb->s_blocksize && i < offset; ) {
148				de = (struct ocfs2_dir_entry *) (bh->b_data + i);
149				/* It's too expensive to do a full
150				 * dirent test each time round this
151				 * loop, but we do have to test at
152				 * least that it is non-zero.  A
153				 * failure will be detected in the
154				 * dirent test below. */
155				if (le16_to_cpu(de->rec_len) <
156				    OCFS2_DIR_REC_LEN(1))
157					break;
158				i += le16_to_cpu(de->rec_len);
159			}
160			offset = i;
161			filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
162				| offset;
163			filp->f_version = inode->i_version;
164		}
165
166		while (!error && filp->f_pos < i_size_read(inode)
167		       && offset < sb->s_blocksize) {
168			de = (struct ocfs2_dir_entry *) (bh->b_data + offset);
169			if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
170				/* On error, skip the f_pos to the
171				   next block. */
172				filp->f_pos = (filp->f_pos |
173					       (sb->s_blocksize - 1)) + 1;
174				brelse(bh);
175				goto bail;
176			}
177			offset += le16_to_cpu(de->rec_len);
178			if (le64_to_cpu(de->inode)) {
179				/* We might block in the next section
180				 * if the data destination is
181				 * currently swapped out.  So, use a
182				 * version stamp to detect whether or
183				 * not the directory has been modified
184				 * during the copy operation.
185				 */
186				unsigned long version = filp->f_version;
187				unsigned char d_type = DT_UNKNOWN;
188
189				if (de->file_type < OCFS2_FT_MAX)
190					d_type = ocfs2_filetype_table[de->file_type];
191				error = filldir(dirent, de->name,
192						de->name_len,
193						filp->f_pos,
194						ino_from_blkno(sb, le64_to_cpu(de->inode)),
195						d_type);
196				if (error)
197					break;
198				if (version != filp->f_version)
199					goto revalidate;
200				stored ++;
201			}
202			filp->f_pos += le16_to_cpu(de->rec_len);
203		}
204		offset = 0;
205		brelse(bh);
206	}
207
208	stored = 0;
209bail:
210	ocfs2_meta_unlock(inode, lock_level);
211
212bail_nolock:
213	mlog_exit(stored);
214
215	return stored;
216}
217
218/*
219 * NOTE: this should always be called with parent dir i_mutex taken.
220 */
221int ocfs2_find_files_on_disk(const char *name,
222			     int namelen,
223			     u64 *blkno,
224			     struct inode *inode,
225			     struct buffer_head **dirent_bh,
226			     struct ocfs2_dir_entry **dirent)
227{
228	int status = -ENOENT;
229
230	mlog_entry("(name=%.*s, blkno=%p, inode=%p, dirent_bh=%p, dirent=%p)\n",
231		   namelen, name, blkno, inode, dirent_bh, dirent);
232
233	*dirent_bh = ocfs2_find_entry(name, namelen, inode, dirent);
234	if (!*dirent_bh || !*dirent) {
235		status = -ENOENT;
236		goto leave;
237	}
238
239	*blkno = le64_to_cpu((*dirent)->inode);
240
241	status = 0;
242leave:
243	if (status < 0) {
244		*dirent = NULL;
245		if (*dirent_bh) {
246			brelse(*dirent_bh);
247			*dirent_bh = NULL;
248		}
249	}
250
251	mlog_exit(status);
252	return status;
253}
254
255/* Check for a name within a directory.
256 *
257 * Return 0 if the name does not exist
258 * Return -EEXIST if the directory contains the name
259 *
260 * Callers should have i_mutex + a cluster lock on dir
261 */
262int ocfs2_check_dir_for_entry(struct inode *dir,
263			      const char *name,
264			      int namelen)
265{
266	int ret;
267	struct buffer_head *dirent_bh = NULL;
268	struct ocfs2_dir_entry *dirent = NULL;
269
270	mlog_entry("dir %llu, name '%.*s'\n",
271		   (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);
272
273	ret = -EEXIST;
274	dirent_bh = ocfs2_find_entry(name, namelen, dir, &dirent);
275	if (dirent_bh)
276		goto bail;
277
278	ret = 0;
279bail:
280	if (dirent_bh)
281		brelse(dirent_bh);
282
283	mlog_exit(ret);
284	return ret;
285}
286
287/*
288 * routine to check that the specified directory is empty (for rmdir)
289 */
290int ocfs2_empty_dir(struct inode *inode)
291{
292	unsigned long offset;
293	struct buffer_head * bh;
294	struct ocfs2_dir_entry * de, * de1;
295	struct super_block * sb;
296	int err;
297
298	sb = inode->i_sb;
299	if ((i_size_read(inode) <
300	     (OCFS2_DIR_REC_LEN(1) + OCFS2_DIR_REC_LEN(2))) ||
301	    !(bh = ocfs2_bread(inode, 0, &err, 0))) {
302	    	mlog(ML_ERROR, "bad directory (dir #%llu) - no data block\n",
303		     (unsigned long long)OCFS2_I(inode)->ip_blkno);
304		return 1;
305	}
306
307	de = (struct ocfs2_dir_entry *) bh->b_data;
308	de1 = (struct ocfs2_dir_entry *)
309			((char *)de + le16_to_cpu(de->rec_len));
310	if ((le64_to_cpu(de->inode) != OCFS2_I(inode)->ip_blkno) ||
311			!le64_to_cpu(de1->inode) ||
312			strcmp(".", de->name) ||
313			strcmp("..", de1->name)) {
314	    	mlog(ML_ERROR, "bad directory (dir #%llu) - no `.' or `..'\n",
315		     (unsigned long long)OCFS2_I(inode)->ip_blkno);
316		brelse(bh);
317		return 1;
318	}
319	offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
320	de = (struct ocfs2_dir_entry *)((char *)de1 + le16_to_cpu(de1->rec_len));
321	while (offset < i_size_read(inode) ) {
322		if (!bh || (void *)de >= (void *)(bh->b_data + sb->s_blocksize)) {
323			brelse(bh);
324			bh = ocfs2_bread(inode,
325					 offset >> sb->s_blocksize_bits, &err, 0);
326			if (!bh) {
327				mlog(ML_ERROR, "dir %llu has a hole at %lu\n",
328				     (unsigned long long)OCFS2_I(inode)->ip_blkno, offset);
329				offset += sb->s_blocksize;
330				continue;
331			}
332			de = (struct ocfs2_dir_entry *) bh->b_data;
333		}
334		if (!ocfs2_check_dir_entry(inode, de, bh, offset)) {
335			brelse(bh);
336			return 1;
337		}
338		if (le64_to_cpu(de->inode)) {
339			brelse(bh);
340			return 0;
341		}
342		offset += le16_to_cpu(de->rec_len);
343		de = (struct ocfs2_dir_entry *)
344			((char *)de + le16_to_cpu(de->rec_len));
345	}
346	brelse(bh);
347	return 1;
348}
349
350/* returns a bh of the 1st new block in the allocation. */
351int ocfs2_do_extend_dir(struct super_block *sb,
352			handle_t *handle,
353			struct inode *dir,
354			struct buffer_head *parent_fe_bh,
355			struct ocfs2_alloc_context *data_ac,
356			struct ocfs2_alloc_context *meta_ac,
357			struct buffer_head **new_bh)
358{
359	int status;
360	int extend;
361	u64 p_blkno, v_blkno;
362
363	spin_lock(&OCFS2_I(dir)->ip_lock);
364	extend = (i_size_read(dir) == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters));
365	spin_unlock(&OCFS2_I(dir)->ip_lock);
366
367	if (extend) {
368		u32 offset = OCFS2_I(dir)->ip_clusters;
369
370		status = ocfs2_do_extend_allocation(OCFS2_SB(sb), dir, &offset,
371						    1, parent_fe_bh, handle,
372						    data_ac, meta_ac, NULL);
373		BUG_ON(status == -EAGAIN);
374		if (status < 0) {
375			mlog_errno(status);
376			goto bail;
377		}
378	}
379
380	v_blkno = ocfs2_blocks_for_bytes(sb, i_size_read(dir));
381	status = ocfs2_extent_map_get_blocks(dir, v_blkno, &p_blkno, NULL, NULL);
382	if (status < 0) {
383		mlog_errno(status);
384		goto bail;
385	}
386
387	*new_bh = sb_getblk(sb, p_blkno);
388	if (!*new_bh) {
389		status = -EIO;
390		mlog_errno(status);
391		goto bail;
392	}
393	status = 0;
394bail:
395	mlog_exit(status);
396	return status;
397}
398
399/* assumes you already have a cluster lock on the directory. */
400static int ocfs2_extend_dir(struct ocfs2_super *osb,
401			    struct inode *dir,
402			    struct buffer_head *parent_fe_bh,
403			    struct buffer_head **new_de_bh)
404{
405	int status = 0;
406	int credits, num_free_extents, drop_alloc_sem = 0;
407	loff_t dir_i_size;
408	struct ocfs2_dinode *fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
409	struct ocfs2_alloc_context *data_ac = NULL;
410	struct ocfs2_alloc_context *meta_ac = NULL;
411	handle_t *handle = NULL;
412	struct buffer_head *new_bh = NULL;
413	struct ocfs2_dir_entry * de;
414	struct super_block *sb = osb->sb;
415
416	mlog_entry_void();
417
418	dir_i_size = i_size_read(dir);
419	mlog(0, "extending dir %llu (i_size = %lld)\n",
420	     (unsigned long long)OCFS2_I(dir)->ip_blkno, dir_i_size);
421
422	/* dir->i_size is always block aligned. */
423	spin_lock(&OCFS2_I(dir)->ip_lock);
424	if (dir_i_size == ocfs2_clusters_to_bytes(sb, OCFS2_I(dir)->ip_clusters)) {
425		spin_unlock(&OCFS2_I(dir)->ip_lock);
426		num_free_extents = ocfs2_num_free_extents(osb, dir, fe);
427		if (num_free_extents < 0) {
428			status = num_free_extents;
429			mlog_errno(status);
430			goto bail;
431		}
432
433		if (!num_free_extents) {
434			status = ocfs2_reserve_new_metadata(osb, fe, &meta_ac);
435			if (status < 0) {
436				if (status != -ENOSPC)
437					mlog_errno(status);
438				goto bail;
439			}
440		}
441
442		status = ocfs2_reserve_clusters(osb, 1, &data_ac);
443		if (status < 0) {
444			if (status != -ENOSPC)
445				mlog_errno(status);
446			goto bail;
447		}
448
449		credits = ocfs2_calc_extend_credits(sb, fe, 1);
450	} else {
451		spin_unlock(&OCFS2_I(dir)->ip_lock);
452		credits = OCFS2_SIMPLE_DIR_EXTEND_CREDITS;
453	}
454
455	down_write(&OCFS2_I(dir)->ip_alloc_sem);
456	drop_alloc_sem = 1;
457
458	handle = ocfs2_start_trans(osb, credits);
459	if (IS_ERR(handle)) {
460		status = PTR_ERR(handle);
461		handle = NULL;
462		mlog_errno(status);
463		goto bail;
464	}
465
466	status = ocfs2_do_extend_dir(osb->sb, handle, dir, parent_fe_bh,
467				     data_ac, meta_ac, &new_bh);
468	if (status < 0) {
469		mlog_errno(status);
470		goto bail;
471	}
472
473	ocfs2_set_new_buffer_uptodate(dir, new_bh);
474
475	status = ocfs2_journal_access(handle, dir, new_bh,
476				      OCFS2_JOURNAL_ACCESS_CREATE);
477	if (status < 0) {
478		mlog_errno(status);
479		goto bail;
480	}
481	memset(new_bh->b_data, 0, sb->s_blocksize);
482	de = (struct ocfs2_dir_entry *) new_bh->b_data;
483	de->inode = 0;
484	de->rec_len = cpu_to_le16(sb->s_blocksize);
485	status = ocfs2_journal_dirty(handle, new_bh);
486	if (status < 0) {
487		mlog_errno(status);
488		goto bail;
489	}
490
491	dir_i_size += dir->i_sb->s_blocksize;
492	i_size_write(dir, dir_i_size);
493	dir->i_blocks = ocfs2_inode_sector_count(dir);
494	status = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
495	if (status < 0) {
496		mlog_errno(status);
497		goto bail;
498	}
499
500	*new_de_bh = new_bh;
501	get_bh(*new_de_bh);
502bail:
503	if (drop_alloc_sem)
504		up_write(&OCFS2_I(dir)->ip_alloc_sem);
505	if (handle)
506		ocfs2_commit_trans(osb, handle);
507
508	if (data_ac)
509		ocfs2_free_alloc_context(data_ac);
510	if (meta_ac)
511		ocfs2_free_alloc_context(meta_ac);
512
513	if (new_bh)
514		brelse(new_bh);
515
516	mlog_exit(status);
517	return status;
518}
519
520/*
521 * Search the dir for a good spot, extending it if necessary. The
522 * block containing an appropriate record is returned in ret_de_bh.
523 */
524int ocfs2_prepare_dir_for_insert(struct ocfs2_super *osb,
525				 struct inode *dir,
526				 struct buffer_head *parent_fe_bh,
527				 const char *name,
528				 int namelen,
529				 struct buffer_head **ret_de_bh)
530{
531	unsigned long offset;
532	struct buffer_head * bh = NULL;
533	unsigned short rec_len;
534	struct ocfs2_dinode *fe;
535	struct ocfs2_dir_entry *de;
536	struct super_block *sb;
537	int status;
538
539	mlog_entry_void();
540
541	mlog(0, "getting ready to insert namelen %d into dir %llu\n",
542	     namelen, (unsigned long long)OCFS2_I(dir)->ip_blkno);
543
544	BUG_ON(!S_ISDIR(dir->i_mode));
545	fe = (struct ocfs2_dinode *) parent_fe_bh->b_data;
546	BUG_ON(le64_to_cpu(fe->i_size) != i_size_read(dir));
547
548	sb = dir->i_sb;
549
550	if (!namelen) {
551		status = -EINVAL;
552		mlog_errno(status);
553		goto bail;
554	}
555
556	bh = ocfs2_bread(dir, 0, &status, 0);
557	if (!bh) {
558		mlog_errno(status);
559		goto bail;
560	}
561
562	rec_len = OCFS2_DIR_REC_LEN(namelen);
563	offset = 0;
564	de = (struct ocfs2_dir_entry *) bh->b_data;
565	while (1) {
566		if ((char *)de >= sb->s_blocksize + bh->b_data) {
567			brelse(bh);
568			bh = NULL;
569
570			if (i_size_read(dir) <= offset) {
571				status = ocfs2_extend_dir(osb,
572							  dir,
573							  parent_fe_bh,
574							  &bh);
575				if (status < 0) {
576					mlog_errno(status);
577					goto bail;
578				}
579				BUG_ON(!bh);
580				*ret_de_bh = bh;
581				get_bh(*ret_de_bh);
582				goto bail;
583			}
584			bh = ocfs2_bread(dir,
585					 offset >> sb->s_blocksize_bits,
586					 &status,
587					 0);
588			if (!bh) {
589				mlog_errno(status);
590				goto bail;
591			}
592			/* move to next block */
593			de = (struct ocfs2_dir_entry *) bh->b_data;
594		}
595		if (!ocfs2_check_dir_entry(dir, de, bh, offset)) {
596			status = -ENOENT;
597			goto bail;
598		}
599		if (ocfs2_match(namelen, name, de)) {
600			status = -EEXIST;
601			goto bail;
602		}
603		if (((le64_to_cpu(de->inode) == 0) &&
604		     (le16_to_cpu(de->rec_len) >= rec_len)) ||
605		    (le16_to_cpu(de->rec_len) >=
606		     (OCFS2_DIR_REC_LEN(de->name_len) + rec_len))) {
607			/* Ok, we found a spot. Return this bh and let
608			 * the caller actually fill it in. */
609			*ret_de_bh = bh;
610			get_bh(*ret_de_bh);
611			status = 0;
612			goto bail;
613		}
614		offset += le16_to_cpu(de->rec_len);
615		de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
616	}
617
618	status = 0;
619bail:
620	if (bh)
621		brelse(bh);
622
623	mlog_exit(status);
624	return status;
625}
626