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33 * @(#)ffs_balloc.c 8.8 (Berkeley) 6/16/95
34 * $FreeBSD: src/sys/ufs/ffs/ffs_balloc.c,v 1.26.2.1 2002/10/10 19:48:20 dillon Exp $
35 * $DragonFly: src/sys/vfs/ufs/ffs_balloc.c,v 1.19 2008/05/21 18:49:49 dillon Exp $
38 #include <sys/param.h>
39 #include <sys/systm.h>
43 #include <sys/mount.h>
44 #include <sys/vnode.h>
48 #include "ufs_extern.h"
51 #include "ffs_extern.h"
54 * ffs_balloc(struct vnode *a_vp, ufs_daddr_t a_lbn, int a_size,
55 * struct ucred *a_cred, int a_flags, struct buf *a_bpp)
57 * Balloc defines the structure of filesystem storage by allocating
58 * the physical blocks on a device given the inode and the logical
59 * block number in a file.
61 * NOTE: B_CLRBUF - this flag tells balloc to clear invalid portions
62 * of the buffer. However, any dirty bits will override missing
63 * valid bits. This case occurs when writable mmaps are truncated
67 ffs_balloc(struct vop_balloc_args *ap)
76 struct buf *bp, *nbp, *dbp;
78 struct indir indirs[NIADDR + 2];
79 ufs_daddr_t newb, *bap, pref;
80 int deallocated, osize, nsize, num, i, error;
81 ufs_daddr_t *allocib, *blkp, *allocblk, allociblk[NIADDR + 1];
82 ufs_daddr_t *lbns_remfree, lbns[NIADDR + 1];
89 lbn = lblkno(fs, ap->a_startoffset);
90 size = blkoff(fs, ap->a_startoffset) + ap->a_size;
91 if (size > fs->fs_bsize)
92 panic("ffs_balloc: blk too big");
100 * The vnode must be locked for us to be able to safely mess
101 * around with the inode.
103 if (vn_islocked(vp) != LK_EXCLUSIVE) {
104 panic("ffs_balloc: vnode %p not exclusively locked!", vp);
108 * If the next write will extend the file into a new block,
109 * and the file is currently composed of a fragment
110 * this fragment has to be extended to be a full block.
112 nb = lblkno(fs, ip->i_size);
113 if (nb < NDADDR && nb < lbn) {
115 * The filesize prior to this write can fit in direct
116 * blocks (ex. fragmentation is possibly done)
117 * we are now extending the file write beyond
118 * the block which has end of the file prior to this write.
120 osize = blksize(fs, ip, nb);
122 * osize gives disk allocated size in the last block. It is
123 * either in fragments or a file system block size.
125 if (osize < fs->fs_bsize && osize > 0) {
126 /* A few fragments are already allocated, since the
127 * current extends beyond this block allocated the
128 * complete block as fragments are on in last block.
130 error = ffs_realloccg(ip, nb,
131 ffs_blkpref(ip, nb, (int)nb, &ip->i_db[0]),
132 osize, (int)fs->fs_bsize, cred, &bp);
135 if (DOINGSOFTDEP(vp))
136 softdep_setup_allocdirect(ip, nb,
137 dofftofsb(fs, bp->b_bio2.bio_offset),
138 ip->i_db[nb], fs->fs_bsize, osize, bp);
139 /* adjust the inode size, we just grew */
140 ip->i_size = smalllblktosize(fs, nb + 1);
141 ip->i_db[nb] = dofftofsb(fs, bp->b_bio2.bio_offset);
142 ip->i_flag |= IN_CHANGE | IN_UPDATE;
147 /* bp is already released here */
151 * The first NDADDR blocks are direct blocks
155 if (nb != 0 && ip->i_size >= smalllblktosize(fs, lbn + 1)) {
156 error = bread(vp, lblktodoff(fs, lbn), fs->fs_bsize, &bp);
161 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
167 * Consider need to reallocate a fragment.
169 osize = fragroundup(fs, blkoff(fs, ip->i_size));
170 nsize = fragroundup(fs, size);
171 if (nsize <= osize) {
172 error = bread(vp, lblktodoff(fs, lbn),
178 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
181 * NOTE: ffs_realloccg() issues a bread().
183 error = ffs_realloccg(ip, lbn,
184 ffs_blkpref(ip, lbn, (int)lbn,
185 &ip->i_db[0]), osize, nsize, cred, &bp);
188 if (DOINGSOFTDEP(vp))
189 softdep_setup_allocdirect(ip, lbn,
190 dofftofsb(fs, bp->b_bio2.bio_offset),
191 nb, nsize, osize, bp);
194 if (ip->i_size < smalllblktosize(fs, lbn + 1))
195 nsize = fragroundup(fs, size);
197 nsize = fs->fs_bsize;
198 error = ffs_alloc(ip, lbn,
199 ffs_blkpref(ip, lbn, (int)lbn, &ip->i_db[0]),
203 bp = getblk(vp, lblktodoff(fs, lbn), nsize, 0, 0);
204 bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
205 if (flags & B_CLRBUF)
207 if (DOINGSOFTDEP(vp))
208 softdep_setup_allocdirect(ip, lbn, newb, 0,
211 ip->i_db[lbn] = dofftofsb(fs, bp->b_bio2.bio_offset);
212 ip->i_flag |= IN_CHANGE | IN_UPDATE;
217 * Determine the number of levels of indirection.
220 if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
224 panic ("ffs_balloc: ufs_bmaparray returned indirect block");
227 * Get a handle on the data block buffer before working through
228 * indirect blocks to avoid a deadlock between the VM system holding
229 * a locked VM page and issuing a BMAP (which tries to lock the
230 * indirect blocks), and the filesystem holding a locked indirect
231 * block and then trying to read a data block (which tries to lock
232 * the underlying VM pages).
234 dbp = getblk(vp, lblktodoff(fs, lbn), fs->fs_bsize, 0, 0);
240 allocblk = allociblk;
246 * Fetch the first indirect block directly from the inode, allocating
250 nb = ip->i_ib[indirs[0].in_off];
252 pref = ffs_blkpref(ip, lbn, 0, NULL);
254 * If the filesystem has run out of space we can skip the
255 * full fsync/undo of the main [fail] case since no undo
256 * history has been built yet. Hence the goto fail2.
258 if ((error = ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize,
263 *lbns_remfree++ = indirs[1].in_lbn;
264 bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
266 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
268 if (DOINGSOFTDEP(vp)) {
269 softdep_setup_allocdirect(ip, NDADDR + indirs[0].in_off,
270 newb, 0, fs->fs_bsize, 0, bp);
274 * Write synchronously so that indirect blocks
275 * never point at garbage.
279 else if ((error = bwrite(bp)) != 0)
282 allocib = &ip->i_ib[indirs[0].in_off];
284 ip->i_flag |= IN_CHANGE | IN_UPDATE;
288 * Fetch through the indirect blocks, allocating as necessary.
291 error = bread(vp, lblktodoff(fs, indirs[i].in_lbn), (int)fs->fs_bsize, &bp);
296 bap = (ufs_daddr_t *)bp->b_data;
297 nb = bap[indirs[i].in_off];
306 pref = ffs_blkpref(ip, lbn, 0, NULL);
308 ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize, cred, &newb)) != 0) {
314 *lbns_remfree++ = indirs[i].in_lbn;
315 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
317 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
319 if (DOINGSOFTDEP(vp)) {
320 softdep_setup_allocindir_meta(nbp, ip, bp,
321 indirs[i - 1].in_off, nb);
325 * Write synchronously so that indirect blocks
326 * never point at garbage.
328 if ((error = bwrite(nbp)) != 0) {
333 bap[indirs[i - 1].in_off] = nb;
334 if (allocib == NULL && unwindidx < 0)
337 * If required, write synchronously, otherwise use
340 if (flags & B_SYNC) {
343 if (bp->b_bufsize == fs->fs_bsize)
344 bp->b_flags |= B_CLUSTEROK;
350 * Get the data block, allocating if necessary. We have already
351 * called getblk() on the data block buffer, dbp. If we have to
352 * allocate it and B_CLRBUF has been set the inference is an intention
353 * to zero out the related disk blocks, so we do not have to issue
354 * a read. Instead we simply call vfs_bio_clrbuf(). If B_CLRBUF is
355 * not set the caller intends to overwrite the entire contents of the
356 * buffer and we don't waste time trying to clean up the contents.
358 * bp references the current indirect block. When allocating,
359 * the block must be updated.
362 pref = ffs_blkpref(ip, lbn, indirs[i].in_off, &bap[0]);
363 error = ffs_alloc(ip,
364 lbn, pref, (int)fs->fs_bsize, cred, &newb);
371 *lbns_remfree++ = lbn;
372 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
373 if (flags & B_CLRBUF)
375 if (DOINGSOFTDEP(vp))
376 softdep_setup_allocindir_page(ip, lbn, bp,
377 indirs[i].in_off, nb, 0, dbp);
378 bap[indirs[i].in_off] = nb;
380 * If required, write synchronously, otherwise use
383 if (flags & B_SYNC) {
386 if (bp->b_bufsize == fs->fs_bsize)
387 bp->b_flags |= B_CLUSTEROK;
396 * At this point all related indirect blocks have been allocated
397 * if necessary and released. bp is no longer valid. dbp holds
398 * our getblk()'d data block.
400 * XXX we previously performed a cluster_read operation here.
402 if (flags & B_CLRBUF) {
404 * If B_CLRBUF is set we must validate the invalid portions
405 * of the buffer. This typically requires a read-before-
406 * write. The strategy call will fill in bio_offset in that
409 * If we hit this case we do a cluster read if possible
410 * since nearby data blocks are likely to be accessed soon
413 if ((dbp->b_flags & B_CACHE) == 0) {
415 seqcount = (flags & B_SEQMASK) >> B_SEQSHIFT;
417 (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
418 error = cluster_read(vp, (off_t)ip->i_size,
425 error = bread(vp, lblktodoff(fs, lbn),
426 (int)fs->fs_bsize, &dbp);
431 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
435 * If B_CLRBUF is not set the caller intends to overwrite
436 * the entire contents of the buffer. We can simply set
437 * bio_offset and we are done.
439 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
445 * If we have failed part way through block allocation, we
446 * have to deallocate any indirect blocks that we have allocated.
447 * We have to fsync the file before we start to get rid of all
448 * of its dependencies so that we do not leave them dangling.
449 * We have to sync it at the end so that the soft updates code
450 * does not find any untracked changes. Although this is really
451 * slow, running out of disk space is not expected to be a common
452 * occurence. The error return from fsync is ignored as we already
453 * have an error to return to the user.
455 VOP_FSYNC(vp, MNT_WAIT, 0);
456 for (deallocated = 0, blkp = allociblk, lbns_remfree = lbns;
457 blkp < allocblk; blkp++, lbns_remfree++) {
459 * We shall not leave the freed blocks on the vnode
460 * buffer object lists.
462 bp = getblk(vp, *lbns_remfree, fs->fs_bsize, 0, 0);
463 bp->b_flags |= (B_INVAL | B_RELBUF);
465 deallocated += fs->fs_bsize;
468 if (allocib != NULL) {
470 } else if (unwindidx >= 0) {
473 r = bread(vp, lblktodoff(fs, indirs[unwindidx].in_lbn), (int)fs->fs_bsize, &bp);
475 panic("Could not unwind indirect block, error %d", r);
478 bap = (ufs_daddr_t *)bp->b_data;
479 bap[indirs[unwindidx].in_off] = 0;
480 if (flags & B_SYNC) {
483 if (bp->b_bufsize == fs->fs_bsize)
484 bp->b_flags |= B_CLUSTEROK;
492 * Restore user's disk quota because allocation failed.
494 (void) ufs_chkdq(ip, (long)-btodb(deallocated), cred, FORCE);
496 ip->i_blocks -= btodb(deallocated);
497 ip->i_flag |= IN_CHANGE | IN_UPDATE;
499 VOP_FSYNC(vp, MNT_WAIT, 0);
502 * After the buffers are invalidated and on-disk pointers are
503 * cleared, free the blocks.
505 for (blkp = allociblk; blkp < allocblk; blkp++) {
506 ffs_blkfree(ip, *blkp, fs->fs_bsize);
510 * Cleanup the data block we getblk()'d before returning.