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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 1.15 2006/03/24 18:35:34 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 * Balloc defines the structure of filesystem storage
55 * by allocating the physical blocks on a device given
56 * the inode and the logical block number in a file.
58 * ffs_balloc(struct vnode *a_vp, ufs_daddr_t a_lbn, int a_size,
59 * struct ucred *a_cred, int a_flags, struct buf *a_bpp)
62 ffs_balloc(struct vop_balloc_args *ap)
71 struct buf *bp, *nbp, *dbp;
73 struct indir indirs[NIADDR + 2];
74 ufs_daddr_t newb, *bap, pref;
75 int deallocated, osize, nsize, num, i, error;
76 ufs_daddr_t *allocib, *blkp, *allocblk, allociblk[NIADDR + 1];
77 struct thread *td = curthread; /* XXX */
84 lbn = lblkno(fs, ap->a_startoffset);
85 size = blkoff(fs, ap->a_startoffset) + ap->a_size;
86 if (size > fs->fs_bsize)
87 panic("ffs_balloc: blk too big");
95 * The vnode must be locked for us to be able to safely mess
96 * around with the inode.
98 if (VOP_ISLOCKED(vp, td) != LK_EXCLUSIVE) {
99 panic("ffs_balloc: vnode %p not exclusively locked!", vp);
103 * If the next write will extend the file into a new block,
104 * and the file is currently composed of a fragment
105 * this fragment has to be extended to be a full block.
107 nb = lblkno(fs, ip->i_size);
108 if (nb < NDADDR && nb < lbn) {
110 * The filesize prior to this write can fit in direct
111 * blocks (ex. fragmentation is possibly done)
112 * we are now extending the file write beyond
113 * the block which has end of the file prior to this write.
115 osize = blksize(fs, ip, nb);
117 * osize gives disk allocated size in the last block. It is
118 * either in fragments or a file system block size.
120 if (osize < fs->fs_bsize && osize > 0) {
121 /* A few fragments are already allocated, since the
122 * current extends beyond this block allocated the
123 * complete block as fragments are on in last block.
125 error = ffs_realloccg(ip, nb,
126 ffs_blkpref(ip, nb, (int)nb, &ip->i_db[0]),
127 osize, (int)fs->fs_bsize, cred, &bp);
130 if (DOINGSOFTDEP(vp))
131 softdep_setup_allocdirect(ip, nb,
132 dofftofsb(fs, bp->b_bio2.bio_offset),
133 ip->i_db[nb], fs->fs_bsize, osize, bp);
134 /* adjust the inode size, we just grew */
135 ip->i_size = smalllblktosize(fs, nb + 1);
136 ip->i_db[nb] = dofftofsb(fs, bp->b_bio2.bio_offset);
137 ip->i_flag |= IN_CHANGE | IN_UPDATE;
142 /* bp is already released here */
146 * The first NDADDR blocks are direct blocks
150 if (nb != 0 && ip->i_size >= smalllblktosize(fs, lbn + 1)) {
151 error = bread(vp, lblktodoff(fs, lbn), fs->fs_bsize, &bp);
156 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
162 * Consider need to reallocate a fragment.
164 osize = fragroundup(fs, blkoff(fs, ip->i_size));
165 nsize = fragroundup(fs, size);
166 if (nsize <= osize) {
167 error = bread(vp, lblktodoff(fs, lbn),
173 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
175 error = ffs_realloccg(ip, lbn,
176 ffs_blkpref(ip, lbn, (int)lbn,
177 &ip->i_db[0]), osize, nsize, cred, &bp);
180 if (DOINGSOFTDEP(vp))
181 softdep_setup_allocdirect(ip, lbn,
182 dofftofsb(fs, bp->b_bio2.bio_offset),
183 nb, nsize, osize, bp);
186 if (ip->i_size < smalllblktosize(fs, lbn + 1))
187 nsize = fragroundup(fs, size);
189 nsize = fs->fs_bsize;
190 error = ffs_alloc(ip, lbn,
191 ffs_blkpref(ip, lbn, (int)lbn, &ip->i_db[0]),
195 bp = getblk(vp, lblktodoff(fs, lbn), nsize, 0, 0);
196 bp->b_bio2.bio_offset = fsbtodoff(fs, newb);
197 if (flags & B_CLRBUF)
199 if (DOINGSOFTDEP(vp))
200 softdep_setup_allocdirect(ip, lbn, newb, 0,
203 ip->i_db[lbn] = dofftofsb(fs, bp->b_bio2.bio_offset);
204 ip->i_flag |= IN_CHANGE | IN_UPDATE;
209 * Determine the number of levels of indirection.
212 if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
216 panic ("ffs_balloc: ufs_bmaparray returned indirect block");
219 * Get a handle on the data block buffer before working through
220 * indirect blocks to avoid a deadlock between the VM system holding
221 * a locked VM page and issuing a BMAP (which tries to lock the
222 * indirect blocks), and the filesystem holding a locked indirect
223 * block and then trying to read a data block (which tries to lock
224 * the underlying VM pages).
226 dbp = getblk(vp, lblktodoff(fs, lbn), fs->fs_bsize, 0, 0);
232 allocblk = allociblk;
236 * Fetch the first indirect block directly from the inode, allocating
240 nb = ip->i_ib[indirs[0].in_off];
242 pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
244 * If the filesystem has run out of space we can skip the
245 * full fsync/undo of the main [fail] case since no undo
246 * history has been built yet. Hence the goto fail2.
248 if ((error = ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize,
253 bp = getblk(vp, lblktodoff(fs, indirs[1].in_lbn),
255 bp->b_bio2.bio_offset = fsbtodoff(fs, nb);
257 if (DOINGSOFTDEP(vp)) {
258 softdep_setup_allocdirect(ip, NDADDR + indirs[0].in_off,
259 newb, 0, fs->fs_bsize, 0, bp);
263 * Write synchronously so that indirect blocks
264 * never point at garbage.
268 else if ((error = bwrite(bp)) != 0)
271 allocib = &ip->i_ib[indirs[0].in_off];
273 ip->i_flag |= IN_CHANGE | IN_UPDATE;
277 * Fetch through the indirect blocks, allocating as necessary.
280 error = bread(vp, lblktodoff(fs, indirs[i].in_lbn), (int)fs->fs_bsize, &bp);
285 bap = (ufs_daddr_t *)bp->b_data;
286 nb = bap[indirs[i].in_off];
295 pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
297 ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize, cred, &newb)) != 0) {
303 nbp = getblk(vp, lblktodoff(fs, indirs[i].in_lbn),
305 nbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
307 if (DOINGSOFTDEP(vp)) {
308 softdep_setup_allocindir_meta(nbp, ip, bp,
309 indirs[i - 1].in_off, nb);
313 * Write synchronously so that indirect blocks
314 * never point at garbage.
316 if ((error = bwrite(nbp)) != 0) {
321 bap[indirs[i - 1].in_off] = nb;
322 if (allocib == NULL && unwindidx < 0)
325 * If required, write synchronously, otherwise use
328 if (flags & B_SYNC) {
331 if (bp->b_bufsize == fs->fs_bsize)
332 bp->b_flags |= B_CLUSTEROK;
338 * Get the data block, allocating if necessary. We have already
339 * called getblk() on the data block buffer, dbp. If we have to
340 * allocate it and B_CLRBUF has been set the inference is an intention
341 * to zero out the related disk blocks, so we do not have to issue
342 * a read. Instead we simply call vfs_bio_clrbuf(). If B_CLRBUF is
343 * not set the caller intends to overwrite the entire contents of the
344 * buffer and we don't waste time trying to clean up the contents.
346 * bp references the current indirect block. When allocating,
347 * the block must be updated.
350 pref = ffs_blkpref(ip, lbn, indirs[i].in_off, &bap[0]);
351 error = ffs_alloc(ip,
352 lbn, pref, (int)fs->fs_bsize, cred, &newb);
359 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
360 if (flags & B_CLRBUF)
362 if (DOINGSOFTDEP(vp))
363 softdep_setup_allocindir_page(ip, lbn, bp,
364 indirs[i].in_off, nb, 0, dbp);
365 bap[indirs[i].in_off] = nb;
367 * If required, write synchronously, otherwise use
370 if (flags & B_SYNC) {
373 if (bp->b_bufsize == fs->fs_bsize)
374 bp->b_flags |= B_CLUSTEROK;
383 * At this point all related indirect blocks have been allocated
384 * if necessary and released. bp is no longer valid. dbp holds
385 * our getblk()'d data block.
387 * XXX we previously performed a cluster_read operation here.
389 if (flags & B_CLRBUF) {
391 * If B_CLRBUF is set we must validate the invalid portions
392 * of the buffer. This typically requires a read-before-
393 * write. The strategy call will fill in bio_offset in that
396 * If we hit this case we do a cluster read if possible
397 * since nearby data blocks are likely to be accessed soon
400 if ((dbp->b_flags & B_CACHE) == 0) {
402 seqcount = (flags & B_SEQMASK) >> B_SEQSHIFT;
404 (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
405 error = cluster_read(vp, (off_t)ip->i_size,
408 MAXBSIZE, seqcount, &dbp);
410 error = bread(vp, lblktodoff(fs, lbn), (int)fs->fs_bsize, &dbp);
415 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
419 * If B_CLRBUF is not set the caller intends to overwrite
420 * the entire contents of the buffer. We can simply set
421 * bio_offset and we are done.
423 dbp->b_bio2.bio_offset = fsbtodoff(fs, nb);
429 * If we have failed part way through block allocation, we
430 * have to deallocate any indirect blocks that we have allocated.
431 * We have to fsync the file before we start to get rid of all
432 * of its dependencies so that we do not leave them dangling.
433 * We have to sync it at the end so that the soft updates code
434 * does not find any untracked changes. Although this is really
435 * slow, running out of disk space is not expected to be a common
436 * occurence. The error return from fsync is ignored as we already
437 * have an error to return to the user.
439 (void) VOP_FSYNC(vp, MNT_WAIT, td);
440 for (deallocated = 0, blkp = allociblk; blkp < allocblk; blkp++) {
441 ffs_blkfree(ip, *blkp, fs->fs_bsize);
442 deallocated += fs->fs_bsize;
444 if (allocib != NULL) {
446 } else if (unwindidx >= 0) {
449 r = bread(vp, lblktodoff(fs, indirs[unwindidx].in_lbn), (int)fs->fs_bsize, &bp);
451 panic("Could not unwind indirect block, error %d", r);
454 bap = (ufs_daddr_t *)bp->b_data;
455 bap[indirs[unwindidx].in_off] = 0;
456 if (flags & B_SYNC) {
459 if (bp->b_bufsize == fs->fs_bsize)
460 bp->b_flags |= B_CLUSTEROK;
468 * Restore user's disk quota because allocation failed.
470 (void) chkdq(ip, (long)-btodb(deallocated), cred, FORCE);
472 ip->i_blocks -= btodb(deallocated);
473 ip->i_flag |= IN_CHANGE | IN_UPDATE;
475 (void) VOP_FSYNC(vp, MNT_WAIT, td);
478 * Cleanup the data block we getblk()'d before returning.