Root/fs/jfs/jfs_extent.c

1/*
2 * Copyright (C) International Business Machines Corp., 2000-2004
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12 * the GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19#include <linux/fs.h>
20#include <linux/quotaops.h>
21#include "jfs_incore.h"
22#include "jfs_inode.h"
23#include "jfs_superblock.h"
24#include "jfs_dmap.h"
25#include "jfs_extent.h"
26#include "jfs_debug.h"
27
28/*
29 * forward references
30 */
31static int extBalloc(struct inode *, s64, s64 *, s64 *);
32#ifdef _NOTYET
33static int extBrealloc(struct inode *, s64, s64, s64 *, s64 *);
34#endif
35static s64 extRoundDown(s64 nb);
36
37#define DPD(a) (printk("(a): %d\n",(a)))
38#define DPC(a) (printk("(a): %c\n",(a)))
39#define DPL1(a) \
40{ \
41    if ((a) >> 32) \
42        printk("(a): %x%08x ",(a)); \
43    else \
44        printk("(a): %x ",(a) << 32); \
45}
46#define DPL(a) \
47{ \
48    if ((a) >> 32) \
49        printk("(a): %x%08x\n",(a)); \
50    else \
51        printk("(a): %x\n",(a) << 32); \
52}
53
54#define DPD1(a) (printk("(a): %d ",(a)))
55#define DPX(a) (printk("(a): %08x\n",(a)))
56#define DPX1(a) (printk("(a): %08x ",(a)))
57#define DPS(a) (printk("%s\n",(a)))
58#define DPE(a) (printk("\nENTERING: %s\n",(a)))
59#define DPE1(a) (printk("\nENTERING: %s",(a)))
60#define DPS1(a) (printk(" %s ",(a)))
61
62
63/*
64 * NAME: extAlloc()
65 *
66 * FUNCTION: allocate an extent for a specified page range within a
67 * file.
68 *
69 * PARAMETERS:
70 * ip - the inode of the file.
71 * xlen - requested extent length.
72 * pno - the starting page number with the file.
73 * xp - pointer to an xad. on entry, xad describes an
74 * extent that is used as an allocation hint if the
75 * xaddr of the xad is non-zero. on successful exit,
76 * the xad describes the newly allocated extent.
77 * abnr - bool indicating whether the newly allocated extent
78 * should be marked as allocated but not recorded.
79 *
80 * RETURN VALUES:
81 * 0 - success
82 * -EIO - i/o error.
83 * -ENOSPC - insufficient disk resources.
84 */
85int
86extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
87{
88    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
89    s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
90    int rc;
91    int xflag;
92
93    /* This blocks if we are low on resources */
94    txBeginAnon(ip->i_sb);
95
96    /* Avoid race with jfs_commit_inode() */
97    mutex_lock(&JFS_IP(ip)->commit_mutex);
98
99    /* validate extent length */
100    if (xlen > MAXXLEN)
101        xlen = MAXXLEN;
102
103    /* get the page's starting extent offset */
104    xoff = pno << sbi->l2nbperpage;
105
106    /* check if an allocation hint was provided */
107    if ((hint = addressXAD(xp))) {
108        /* get the size of the extent described by the hint */
109        nxlen = lengthXAD(xp);
110
111        /* check if the hint is for the portion of the file
112         * immediately previous to the current allocation
113         * request and if hint extent has the same abnr
114         * value as the current request. if so, we can
115         * extend the hint extent to include the current
116         * extent if we can allocate the blocks immediately
117         * following the hint extent.
118         */
119        if (offsetXAD(xp) + nxlen == xoff &&
120            abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
121            xaddr = hint + nxlen;
122
123        /* adjust the hint to the last block of the extent */
124        hint += (nxlen - 1);
125    }
126
127    /* allocate the disk blocks for the extent. initially, extBalloc()
128     * will try to allocate disk blocks for the requested size (xlen).
129     * if this fails (xlen contiguous free blocks not available), it'll
130     * try to allocate a smaller number of blocks (producing a smaller
131     * extent), with this smaller number of blocks consisting of the
132     * requested number of blocks rounded down to the next smaller
133     * power of 2 number (i.e. 16 -> 8). it'll continue to round down
134     * and retry the allocation until the number of blocks to allocate
135     * is smaller than the number of blocks per page.
136     */
137    nxlen = xlen;
138    if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
139        mutex_unlock(&JFS_IP(ip)->commit_mutex);
140        return (rc);
141    }
142
143    /* Allocate blocks to quota. */
144    rc = dquot_alloc_block(ip, nxlen);
145    if (rc) {
146        dbFree(ip, nxaddr, (s64) nxlen);
147        mutex_unlock(&JFS_IP(ip)->commit_mutex);
148        return rc;
149    }
150
151    /* determine the value of the extent flag */
152    xflag = abnr ? XAD_NOTRECORDED : 0;
153
154    /* if we can extend the hint extent to cover the current request,
155     * extend it. otherwise, insert a new extent to
156     * cover the current request.
157     */
158    if (xaddr && xaddr == nxaddr)
159        rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
160    else
161        rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);
162
163    /* if the extend or insert failed,
164     * free the newly allocated blocks and return the error.
165     */
166    if (rc) {
167        dbFree(ip, nxaddr, nxlen);
168        dquot_free_block(ip, nxlen);
169        mutex_unlock(&JFS_IP(ip)->commit_mutex);
170        return (rc);
171    }
172
173    /* set the results of the extent allocation */
174    XADaddress(xp, nxaddr);
175    XADlength(xp, nxlen);
176    XADoffset(xp, xoff);
177    xp->flag = xflag;
178
179    mark_inode_dirty(ip);
180
181    mutex_unlock(&JFS_IP(ip)->commit_mutex);
182    /*
183     * COMMIT_SyncList flags an anonymous tlock on page that is on
184     * sync list.
185     * We need to commit the inode to get the page written disk.
186     */
187    if (test_and_clear_cflag(COMMIT_Synclist,ip))
188        jfs_commit_inode(ip, 0);
189
190    return (0);
191}
192
193
194#ifdef _NOTYET
195/*
196 * NAME: extRealloc()
197 *
198 * FUNCTION: extend the allocation of a file extent containing a
199 * partial back last page.
200 *
201 * PARAMETERS:
202 * ip - the inode of the file.
203 * cp - cbuf for the partial backed last page.
204 * xlen - request size of the resulting extent.
205 * xp - pointer to an xad. on successful exit, the xad
206 * describes the newly allocated extent.
207 * abnr - bool indicating whether the newly allocated extent
208 * should be marked as allocated but not recorded.
209 *
210 * RETURN VALUES:
211 * 0 - success
212 * -EIO - i/o error.
213 * -ENOSPC - insufficient disk resources.
214 */
215int extRealloc(struct inode *ip, s64 nxlen, xad_t * xp, bool abnr)
216{
217    struct super_block *sb = ip->i_sb;
218    s64 xaddr, xlen, nxaddr, delta, xoff;
219    s64 ntail, nextend, ninsert;
220    int rc, nbperpage = JFS_SBI(sb)->nbperpage;
221    int xflag;
222
223    /* This blocks if we are low on resources */
224    txBeginAnon(ip->i_sb);
225
226    mutex_lock(&JFS_IP(ip)->commit_mutex);
227    /* validate extent length */
228    if (nxlen > MAXXLEN)
229        nxlen = MAXXLEN;
230
231    /* get the extend (partial) page's disk block address and
232     * number of blocks.
233     */
234    xaddr = addressXAD(xp);
235    xlen = lengthXAD(xp);
236    xoff = offsetXAD(xp);
237
238    /* if the extend page is abnr and if the request is for
239     * the extent to be allocated and recorded,
240     * make the page allocated and recorded.
241     */
242    if ((xp->flag & XAD_NOTRECORDED) && !abnr) {
243        xp->flag = 0;
244        if ((rc = xtUpdate(0, ip, xp)))
245            goto exit;
246    }
247
248    /* try to allocated the request number of blocks for the
249     * extent. dbRealloc() first tries to satisfy the request
250     * by extending the allocation in place. otherwise, it will
251     * try to allocate a new set of blocks large enough for the
252     * request. in satisfying a request, dbReAlloc() may allocate
253     * less than what was request but will always allocate enough
254     * space as to satisfy the extend page.
255     */
256    if ((rc = extBrealloc(ip, xaddr, xlen, &nxlen, &nxaddr)))
257        goto exit;
258
259    /* Allocat blocks to quota. */
260    rc = dquot_alloc_block(ip, nxlen);
261    if (rc) {
262        dbFree(ip, nxaddr, (s64) nxlen);
263        mutex_unlock(&JFS_IP(ip)->commit_mutex);
264        return rc;
265    }
266
267    delta = nxlen - xlen;
268
269    /* check if the extend page is not abnr but the request is abnr
270     * and the allocated disk space is for more than one page. if this
271     * is the case, there is a miss match of abnr between the extend page
272     * and the one or more pages following the extend page. as a result,
273     * two extents will have to be manipulated. the first will be that
274     * of the extent of the extend page and will be manipulated thru
275     * an xtExtend() or an xtTailgate(), depending upon whether the
276     * disk allocation occurred as an inplace extension. the second
277     * extent will be manipulated (created) through an xtInsert() and
278     * will be for the pages following the extend page.
279     */
280    if (abnr && (!(xp->flag & XAD_NOTRECORDED)) && (nxlen > nbperpage)) {
281        ntail = nbperpage;
282        nextend = ntail - xlen;
283        ninsert = nxlen - nbperpage;
284
285        xflag = XAD_NOTRECORDED;
286    } else {
287        ntail = nxlen;
288        nextend = delta;
289        ninsert = 0;
290
291        xflag = xp->flag;
292    }
293
294    /* if we were able to extend the disk allocation in place,
295     * extend the extent. otherwise, move the extent to a
296     * new disk location.
297     */
298    if (xaddr == nxaddr) {
299        /* extend the extent */
300        if ((rc = xtExtend(0, ip, xoff + xlen, (int) nextend, 0))) {
301            dbFree(ip, xaddr + xlen, delta);
302            dquot_free_block(ip, nxlen);
303            goto exit;
304        }
305    } else {
306        /*
307         * move the extent to a new location:
308         *
309         * xtTailgate() accounts for relocated tail extent;
310         */
311        if ((rc = xtTailgate(0, ip, xoff, (int) ntail, nxaddr, 0))) {
312            dbFree(ip, nxaddr, nxlen);
313            dquot_free_block(ip, nxlen);
314            goto exit;
315        }
316    }
317
318
319    /* check if we need to also insert a new extent */
320    if (ninsert) {
321        /* perform the insert. if it fails, free the blocks
322         * to be inserted and make it appear that we only did
323         * the xtExtend() or xtTailgate() above.
324         */
325        xaddr = nxaddr + ntail;
326        if (xtInsert (0, ip, xflag, xoff + ntail, (int) ninsert,
327                  &xaddr, 0)) {
328            dbFree(ip, xaddr, (s64) ninsert);
329            delta = nextend;
330            nxlen = ntail;
331            xflag = 0;
332        }
333    }
334
335    /* set the return results */
336    XADaddress(xp, nxaddr);
337    XADlength(xp, nxlen);
338    XADoffset(xp, xoff);
339    xp->flag = xflag;
340
341    mark_inode_dirty(ip);
342exit:
343    mutex_unlock(&JFS_IP(ip)->commit_mutex);
344    return (rc);
345}
346#endif /* _NOTYET */
347
348
349/*
350 * NAME: extHint()
351 *
352 * FUNCTION: produce an extent allocation hint for a file offset.
353 *
354 * PARAMETERS:
355 * ip - the inode of the file.
356 * offset - file offset for which the hint is needed.
357 * xp - pointer to the xad that is to be filled in with
358 * the hint.
359 *
360 * RETURN VALUES:
361 * 0 - success
362 * -EIO - i/o error.
363 */
364int extHint(struct inode *ip, s64 offset, xad_t * xp)
365{
366    struct super_block *sb = ip->i_sb;
367    int nbperpage = JFS_SBI(sb)->nbperpage;
368    s64 prev;
369    int rc = 0;
370    s64 xaddr;
371    int xlen;
372    int xflag;
373
374    /* init the hint as "no hint provided" */
375    XADaddress(xp, 0);
376
377    /* determine the starting extent offset of the page previous
378     * to the page containing the offset.
379     */
380    prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;
381
382    /* if the offset is in the first page of the file, no hint provided.
383     */
384    if (prev < 0)
385        goto out;
386
387    rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);
388
389    if ((rc == 0) && xlen) {
390        if (xlen != nbperpage) {
391            jfs_error(ip->i_sb, "extHint: corrupt xtree");
392            rc = -EIO;
393        }
394        XADaddress(xp, xaddr);
395        XADlength(xp, xlen);
396        XADoffset(xp, prev);
397        /*
398         * only preserve the abnr flag within the xad flags
399         * of the returned hint.
400         */
401        xp->flag = xflag & XAD_NOTRECORDED;
402    } else
403        rc = 0;
404
405out:
406    return (rc);
407}
408
409
410/*
411 * NAME: extRecord()
412 *
413 * FUNCTION: change a page with a file from not recorded to recorded.
414 *
415 * PARAMETERS:
416 * ip - inode of the file.
417 * cp - cbuf of the file page.
418 *
419 * RETURN VALUES:
420 * 0 - success
421 * -EIO - i/o error.
422 * -ENOSPC - insufficient disk resources.
423 */
424int extRecord(struct inode *ip, xad_t * xp)
425{
426    int rc;
427
428    txBeginAnon(ip->i_sb);
429
430    mutex_lock(&JFS_IP(ip)->commit_mutex);
431
432    /* update the extent */
433    rc = xtUpdate(0, ip, xp);
434
435    mutex_unlock(&JFS_IP(ip)->commit_mutex);
436    return rc;
437}
438
439
440#ifdef _NOTYET
441/*
442 * NAME: extFill()
443 *
444 * FUNCTION: allocate disk space for a file page that represents
445 * a file hole.
446 *
447 * PARAMETERS:
448 * ip - the inode of the file.
449 * cp - cbuf of the file page represent the hole.
450 *
451 * RETURN VALUES:
452 * 0 - success
453 * -EIO - i/o error.
454 * -ENOSPC - insufficient disk resources.
455 */
456int extFill(struct inode *ip, xad_t * xp)
457{
458    int rc, nbperpage = JFS_SBI(ip->i_sb)->nbperpage;
459    s64 blkno = offsetXAD(xp) >> ip->i_blkbits;
460
461// assert(ISSPARSE(ip));
462
463    /* initialize the extent allocation hint */
464    XADaddress(xp, 0);
465
466    /* allocate an extent to fill the hole */
467    if ((rc = extAlloc(ip, nbperpage, blkno, xp, false)))
468        return (rc);
469
470    assert(lengthPXD(xp) == nbperpage);
471
472    return (0);
473}
474#endif /* _NOTYET */
475
476
477/*
478 * NAME: extBalloc()
479 *
480 * FUNCTION: allocate disk blocks to form an extent.
481 *
482 * initially, we will try to allocate disk blocks for the
483 * requested size (nblocks). if this fails (nblocks
484 * contiguous free blocks not available), we'll try to allocate
485 * a smaller number of blocks (producing a smaller extent), with
486 * this smaller number of blocks consisting of the requested
487 * number of blocks rounded down to the next smaller power of 2
488 * number (i.e. 16 -> 8). we'll continue to round down and
489 * retry the allocation until the number of blocks to allocate
490 * is smaller than the number of blocks per page.
491 *
492 * PARAMETERS:
493 * ip - the inode of the file.
494 * hint - disk block number to be used as an allocation hint.
495 * *nblocks - pointer to an s64 value. on entry, this value specifies
496 * the desired number of block to be allocated. on successful
497 * exit, this value is set to the number of blocks actually
498 * allocated.
499 * blkno - pointer to a block address that is filled in on successful
500 * return with the starting block number of the newly
501 * allocated block range.
502 *
503 * RETURN VALUES:
504 * 0 - success
505 * -EIO - i/o error.
506 * -ENOSPC - insufficient disk resources.
507 */
508static int
509extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
510{
511    struct jfs_inode_info *ji = JFS_IP(ip);
512    struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
513    s64 nb, nblks, daddr, max;
514    int rc, nbperpage = sbi->nbperpage;
515    struct bmap *bmp = sbi->bmap;
516    int ag;
517
518    /* get the number of blocks to initially attempt to allocate.
519     * we'll first try the number of blocks requested unless this
520     * number is greater than the maximum number of contiguous free
521     * blocks in the map. in that case, we'll start off with the
522     * maximum free.
523     */
524    max = (s64) 1 << bmp->db_maxfreebud;
525    if (*nblocks >= max && *nblocks > nbperpage)
526        nb = nblks = (max > nbperpage) ? max : nbperpage;
527    else
528        nb = nblks = *nblocks;
529
530    /* try to allocate blocks */
531    while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
532        /* if something other than an out of space error,
533         * stop and return this error.
534         */
535        if (rc != -ENOSPC)
536            return (rc);
537
538        /* decrease the allocation request size */
539        nb = min(nblks, extRoundDown(nb));
540
541        /* give up if we cannot cover a page */
542        if (nb < nbperpage)
543            return (rc);
544    }
545
546    *nblocks = nb;
547    *blkno = daddr;
548
549    if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
550        ag = BLKTOAG(daddr, sbi);
551        spin_lock_irq(&ji->ag_lock);
552        if (ji->active_ag == -1) {
553            atomic_inc(&bmp->db_active[ag]);
554            ji->active_ag = ag;
555        } else if (ji->active_ag != ag) {
556            atomic_dec(&bmp->db_active[ji->active_ag]);
557            atomic_inc(&bmp->db_active[ag]);
558            ji->active_ag = ag;
559        }
560        spin_unlock_irq(&ji->ag_lock);
561    }
562
563    return (0);
564}
565
566
567#ifdef _NOTYET
568/*
569 * NAME: extBrealloc()
570 *
571 * FUNCTION: attempt to extend an extent's allocation.
572 *
573 * Initially, we will try to extend the extent's allocation
574 * in place. If this fails, we'll try to move the extent
575 * to a new set of blocks. If moving the extent, we initially
576 * will try to allocate disk blocks for the requested size
577 * (newnblks). if this fails (new contiguous free blocks not
578 * available), we'll try to allocate a smaller number of
579 * blocks (producing a smaller extent), with this smaller
580 * number of blocks consisting of the requested number of
581 * blocks rounded down to the next smaller power of 2
582 * number (i.e. 16 -> 8). We'll continue to round down and
583 * retry the allocation until the number of blocks to allocate
584 * is smaller than the number of blocks per page.
585 *
586 * PARAMETERS:
587 * ip - the inode of the file.
588 * blkno - starting block number of the extents current allocation.
589 * nblks - number of blocks within the extents current allocation.
590 * newnblks - pointer to a s64 value. on entry, this value is the
591 * the new desired extent size (number of blocks). on
592 * successful exit, this value is set to the extent's actual
593 * new size (new number of blocks).
594 * newblkno - the starting block number of the extents new allocation.
595 *
596 * RETURN VALUES:
597 * 0 - success
598 * -EIO - i/o error.
599 * -ENOSPC - insufficient disk resources.
600 */
601static int
602extBrealloc(struct inode *ip,
603        s64 blkno, s64 nblks, s64 * newnblks, s64 * newblkno)
604{
605    int rc;
606
607    /* try to extend in place */
608    if ((rc = dbExtend(ip, blkno, nblks, *newnblks - nblks)) == 0) {
609        *newblkno = blkno;
610        return (0);
611    } else {
612        if (rc != -ENOSPC)
613            return (rc);
614    }
615
616    /* in place extension not possible.
617     * try to move the extent to a new set of blocks.
618     */
619    return (extBalloc(ip, blkno, newnblks, newblkno));
620}
621#endif /* _NOTYET */
622
623
624/*
625 * NAME: extRoundDown()
626 *
627 * FUNCTION: round down a specified number of blocks to the next
628 * smallest power of 2 number.
629 *
630 * PARAMETERS:
631 * nb - the inode of the file.
632 *
633 * RETURN VALUES:
634 * next smallest power of 2 number.
635 */
636static s64 extRoundDown(s64 nb)
637{
638    int i;
639    u64 m, k;
640
641    for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
642        if (m & nb)
643            break;
644    }
645
646    i = 63 - i;
647    k = (u64) 1 << i;
648    k = ((k - 1) & nb) ? k : k >> 1;
649
650    return (k);
651}
652

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