summaryrefslogtreecommitdiffstats
path: root/fs/jfs/jfs_extent.c
blob: ae99a7e232eebd1c06aaaf4e8bc9d9ef3f9c95ec (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 */

#include <linux/fs.h>
#include <linux/quotaops.h>
#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_extent.h"
#include "jfs_debug.h"

/*
 * forward references
 */
static int extBalloc(struct inode *, s64, s64 *, s64 *);
static s64 extRoundDown(s64 nb);

#define DPD(a)		(printk("(a): %d\n",(a)))
#define DPC(a)		(printk("(a): %c\n",(a)))
#define DPL1(a)					\
{						\
	if ((a) >> 32)				\
		printk("(a): %x%08x  ",(a));	\
	else					\
		printk("(a): %x  ",(a) << 32);	\
}
#define DPL(a)					\
{						\
	if ((a) >> 32)				\
		printk("(a): %x%08x\n",(a));	\
	else					\
		printk("(a): %x\n",(a) << 32);	\
}

#define DPD1(a)		(printk("(a): %d  ",(a)))
#define DPX(a)		(printk("(a): %08x\n",(a)))
#define DPX1(a)		(printk("(a): %08x  ",(a)))
#define DPS(a)		(printk("%s\n",(a)))
#define DPE(a)		(printk("\nENTERING: %s\n",(a)))
#define DPE1(a)		(printk("\nENTERING: %s",(a)))
#define DPS1(a)		(printk("  %s  ",(a)))


/*
 * NAME:	extAlloc()
 *
 * FUNCTION:	allocate an extent for a specified page range within a
 *		file.
 *
 * PARAMETERS:
 *	ip	- the inode of the file.
 *	xlen	- requested extent length.
 *	pno	- the starting page number with the file.
 *	xp	- pointer to an xad.  on entry, xad describes an
 *		  extent that is used as an allocation hint if the
 *		  xaddr of the xad is non-zero.  on successful exit,
 *		  the xad describes the newly allocated extent.
 *	abnr	- bool indicating whether the newly allocated extent
 *		  should be marked as allocated but not recorded.
 *
 * RETURN VALUES:
 *	0	- success
 *	-EIO	- i/o error.
 *	-ENOSPC	- insufficient disk resources.
 */
int
extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
{
	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
	s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
	int rc;
	int xflag;

	/* This blocks if we are low on resources */
	txBeginAnon(ip->i_sb);

	/* Avoid race with jfs_commit_inode() */
	mutex_lock(&JFS_IP(ip)->commit_mutex);

	/* validate extent length */
	if (xlen > MAXXLEN)
		xlen = MAXXLEN;

	/* get the page's starting extent offset */
	xoff = pno << sbi->l2nbperpage;

	/* check if an allocation hint was provided */
	if ((hint = addressXAD(xp))) {
		/* get the size of the extent described by the hint */
		nxlen = lengthXAD(xp);

		/* check if the hint is for the portion of the file
		 * immediately previous to the current allocation
		 * request and if hint extent has the same abnr
		 * value as the current request.  if so, we can
		 * extend the hint extent to include the current
		 * extent if we can allocate the blocks immediately
		 * following the hint extent.
		 */
		if (offsetXAD(xp) + nxlen == xoff &&
		    abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
			xaddr = hint + nxlen;

		/* adjust the hint to the last block of the extent */
		hint += (nxlen - 1);
	}

	/* allocate the disk blocks for the extent.  initially, extBalloc()
	 * will try to allocate disk blocks for the requested size (xlen).
	 * if this fails (xlen contiguous free blocks not available), it'll
	 * try to allocate a smaller number of blocks (producing a smaller
	 * extent), with this smaller number of blocks consisting of the
	 * requested number of blocks rounded down to the next smaller
	 * power of 2 number (i.e. 16 -> 8).  it'll continue to round down
	 * and retry the allocation until the number of blocks to allocate
	 * is smaller than the number of blocks per page.
	 */
	nxlen = xlen;
	if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
		mutex_unlock(&JFS_IP(ip)->commit_mutex);
		return (rc);
	}

	/* Allocate blocks to quota. */
	rc = dquot_alloc_block(ip, nxlen);
	if (rc) {
		dbFree(ip, nxaddr, (s64) nxlen);
		mutex_unlock(&JFS_IP(ip)->commit_mutex);
		return rc;
	}

	/* determine the value of the extent flag */
	xflag = abnr ? XAD_NOTRECORDED : 0;

	/* if we can extend the hint extent to cover the current request,
	 * extend it.  otherwise, insert a new extent to
	 * cover the current request.
	 */
	if (xaddr && xaddr == nxaddr)
		rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
	else
		rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);

	/* if the extend or insert failed,
	 * free the newly allocated blocks and return the error.
	 */
	if (rc) {
		dbFree(ip, nxaddr, nxlen);
		dquot_free_block(ip, nxlen);
		mutex_unlock(&JFS_IP(ip)->commit_mutex);
		return (rc);
	}

	/* set the results of the extent allocation */
	XADaddress(xp, nxaddr);
	XADlength(xp, nxlen);
	XADoffset(xp, xoff);
	xp->flag = xflag;

	mark_inode_dirty(ip);

	mutex_unlock(&JFS_IP(ip)->commit_mutex);
	/*
	 * COMMIT_SyncList flags an anonymous tlock on page that is on
	 * sync list.
	 * We need to commit the inode to get the page written disk.
	 */
	if (test_and_clear_cflag(COMMIT_Synclist,ip))
		jfs_commit_inode(ip, 0);

	return (0);
}

/*
 * NAME:	extHint()
 *
 * FUNCTION:	produce an extent allocation hint for a file offset.
 *
 * PARAMETERS:
 *	ip	- the inode of the file.
 *	offset  - file offset for which the hint is needed.
 *	xp	- pointer to the xad that is to be filled in with
 *		  the hint.
 *
 * RETURN VALUES:
 *	0	- success
 *	-EIO	- i/o error.
 */
int extHint(struct inode *ip, s64 offset, xad_t * xp)
{
	struct super_block *sb = ip->i_sb;
	int nbperpage = JFS_SBI(sb)->nbperpage;
	s64 prev;
	int rc = 0;
	s64 xaddr;
	int xlen;
	int xflag;

	/* init the hint as "no hint provided" */
	XADaddress(xp, 0);

	/* determine the starting extent offset of the page previous
	 * to the page containing the offset.
	 */
	prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;

	/* if the offset is in the first page of the file, no hint provided.
	 */
	if (prev < 0)
		goto out;

	rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);

	if ((rc == 0) && xlen) {
		if (xlen != nbperpage) {
			jfs_error(ip->i_sb, "corrupt xtree\n");
			rc = -EIO;
		}
		XADaddress(xp, xaddr);
		XADlength(xp, xlen);
		XADoffset(xp, prev);
		/*
		 * only preserve the abnr flag within the xad flags
		 * of the returned hint.
		 */
		xp->flag  = xflag & XAD_NOTRECORDED;
	} else
		rc = 0;

out:
	return (rc);
}


/*
 * NAME:	extRecord()
 *
 * FUNCTION:	change a page with a file from not recorded to recorded.
 *
 * PARAMETERS:
 *	ip	- inode of the file.
 *	cp	- cbuf of the file page.
 *
 * RETURN VALUES:
 *	0	- success
 *	-EIO	- i/o error.
 *	-ENOSPC	- insufficient disk resources.
 */
int extRecord(struct inode *ip, xad_t * xp)
{
	int rc;

	txBeginAnon(ip->i_sb);

	mutex_lock(&JFS_IP(ip)->commit_mutex);

	/* update the extent */
	rc = xtUpdate(0, ip, xp);

	mutex_unlock(&JFS_IP(ip)->commit_mutex);
	return rc;
}

/*
 * NAME:	extBalloc()
 *
 * FUNCTION:	allocate disk blocks to form an extent.
 *
 *		initially, we will try to allocate disk blocks for the
 *		requested size (nblocks).  if this fails (nblocks
 *		contiguous free blocks not available), we'll try to allocate
 *		a smaller number of blocks (producing a smaller extent), with
 *		this smaller number of blocks consisting of the requested
 *		number of blocks rounded down to the next smaller power of 2
 *		number (i.e. 16 -> 8).  we'll continue to round down and
 *		retry the allocation until the number of blocks to allocate
 *		is smaller than the number of blocks per page.
 *
 * PARAMETERS:
 *	ip	 - the inode of the file.
 *	hint	 - disk block number to be used as an allocation hint.
 *	*nblocks - pointer to an s64 value.  on entry, this value specifies
 *		   the desired number of block to be allocated. on successful
 *		   exit, this value is set to the number of blocks actually
 *		   allocated.
 *	blkno	 - pointer to a block address that is filled in on successful
 *		   return with the starting block number of the newly
 *		   allocated block range.
 *
 * RETURN VALUES:
 *	0	- success
 *	-EIO	- i/o error.
 *	-ENOSPC	- insufficient disk resources.
 */
static int
extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
{
	struct jfs_inode_info *ji = JFS_IP(ip);
	struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
	s64 nb, nblks, daddr, max;
	int rc, nbperpage = sbi->nbperpage;
	struct bmap *bmp = sbi->bmap;
	int ag;

	/* get the number of blocks to initially attempt to allocate.
	 * we'll first try the number of blocks requested unless this
	 * number is greater than the maximum number of contiguous free
	 * blocks in the map. in that case, we'll start off with the
	 * maximum free.
	 */
	max = (s64) 1 << bmp->db_maxfreebud;
	if (*nblocks >= max && *nblocks > nbperpage)
		nb = nblks = (max > nbperpage) ? max : nbperpage;
	else
		nb = nblks = *nblocks;

	/* try to allocate blocks */
	while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
		/* if something other than an out of space error,
		 * stop and return this error.
		 */
		if (rc != -ENOSPC)
			return (rc);

		/* decrease the allocation request size */
		nb = min(nblks, extRoundDown(nb));

		/* give up if we cannot cover a page */
		if (nb < nbperpage)
			return (rc);
	}

	*nblocks = nb;
	*blkno = daddr;

	if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
		ag = BLKTOAG(daddr, sbi);
		spin_lock_irq(&ji->ag_lock);
		if (ji->active_ag == -1) {
			atomic_inc(&bmp->db_active[ag]);
			ji->active_ag = ag;
		} else if (ji->active_ag != ag) {
			atomic_dec(&bmp->db_active[ji->active_ag]);
			atomic_inc(&bmp->db_active[ag]);
			ji->active_ag = ag;
		}
		spin_unlock_irq(&ji->ag_lock);
	}

	return (0);
}

/*
 * NAME:	extRoundDown()
 *
 * FUNCTION:	round down a specified number of blocks to the next
 *		smallest power of 2 number.
 *
 * PARAMETERS:
 *	nb	- the inode of the file.
 *
 * RETURN VALUES:
 *	next smallest power of 2 number.
 */
static s64 extRoundDown(s64 nb)
{
	int i;
	u64 m, k;

	for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
		if (m & nb)
			break;
	}

	i = 63 - i;
	k = (u64) 1 << i;
	k = ((k - 1) & nb) ? k : k >> 1;

	return (k);
}