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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 1.14 2006/02/17 19:18:08 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 dbtofsb(fs, bp->b_bio2.bio_blkno),
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] = dbtofsb(fs, bp->b_bio2.bio_blkno);
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, lbn, fs->fs_bsize, &bp);
156 bp->b_bio2.bio_blkno = fsbtodb(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, lbn, osize, &bp);
172 bp->b_bio2.bio_blkno = fsbtodb(fs, nb);
174 error = ffs_realloccg(ip, lbn,
175 ffs_blkpref(ip, lbn, (int)lbn,
176 &ip->i_db[0]), osize, nsize, cred, &bp);
179 if (DOINGSOFTDEP(vp))
180 softdep_setup_allocdirect(ip, lbn,
181 dbtofsb(fs, bp->b_bio2.bio_blkno),
182 nb, nsize, osize, bp);
185 if (ip->i_size < smalllblktosize(fs, lbn + 1))
186 nsize = fragroundup(fs, size);
188 nsize = fs->fs_bsize;
189 error = ffs_alloc(ip, lbn,
190 ffs_blkpref(ip, lbn, (int)lbn, &ip->i_db[0]),
194 bp = getblk(vp, lbn, nsize, 0, 0);
195 bp->b_bio2.bio_blkno = fsbtodb(fs, newb);
196 if (flags & B_CLRBUF)
198 if (DOINGSOFTDEP(vp))
199 softdep_setup_allocdirect(ip, lbn, newb, 0,
202 ip->i_db[lbn] = dbtofsb(fs, bp->b_bio2.bio_blkno);
203 ip->i_flag |= IN_CHANGE | IN_UPDATE;
208 * Determine the number of levels of indirection.
211 if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
215 panic ("ffs_balloc: ufs_bmaparray returned indirect block");
218 * Get a handle on the data block buffer before working through
219 * indirect blocks to avoid a deadlock between the VM system holding
220 * a locked VM page and issuing a BMAP (which tries to lock the
221 * indirect blocks), and the filesystem holding a locked indirect
222 * block and then trying to read a data block (which tries to lock
223 * the underlying VM pages).
225 dbp = getblk(vp, lbn, fs->fs_bsize, 0, 0);
231 allocblk = allociblk;
235 * Fetch the first indirect block directly from the inode, allocating
239 nb = ip->i_ib[indirs[0].in_off];
241 pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
243 * If the filesystem has run out of space we can skip the
244 * full fsync/undo of the main [fail] case since no undo
245 * history has been built yet. Hence the goto fail2.
247 if ((error = ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize,
252 bp = getblk(vp, indirs[1].in_lbn, fs->fs_bsize, 0, 0);
253 bp->b_bio2.bio_blkno = fsbtodb(fs, nb);
255 if (DOINGSOFTDEP(vp)) {
256 softdep_setup_allocdirect(ip, NDADDR + indirs[0].in_off,
257 newb, 0, fs->fs_bsize, 0, bp);
261 * Write synchronously so that indirect blocks
262 * never point at garbage.
266 else if ((error = bwrite(bp)) != 0)
269 allocib = &ip->i_ib[indirs[0].in_off];
271 ip->i_flag |= IN_CHANGE | IN_UPDATE;
275 * Fetch through the indirect blocks, allocating as necessary.
278 error = bread(vp, indirs[i].in_lbn, (int)fs->fs_bsize, &bp);
283 bap = (ufs_daddr_t *)bp->b_data;
284 nb = bap[indirs[i].in_off];
293 pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
295 ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize, cred, &newb)) != 0) {
301 nbp = getblk(vp, indirs[i].in_lbn, fs->fs_bsize, 0, 0);
302 nbp->b_bio2.bio_blkno = fsbtodb(fs, nb);
304 if (DOINGSOFTDEP(vp)) {
305 softdep_setup_allocindir_meta(nbp, ip, bp,
306 indirs[i - 1].in_off, nb);
310 * Write synchronously so that indirect blocks
311 * never point at garbage.
313 if ((error = bwrite(nbp)) != 0) {
318 bap[indirs[i - 1].in_off] = nb;
319 if (allocib == NULL && unwindidx < 0)
322 * If required, write synchronously, otherwise use
325 if (flags & B_SYNC) {
328 if (bp->b_bufsize == fs->fs_bsize)
329 bp->b_flags |= B_CLUSTEROK;
335 * Get the data block, allocating if necessary. We have already
336 * called getblk() on the data block buffer, dbp. If we have to
337 * allocate it and B_CLRBUF has been set the inference is an intention
338 * to zero out the related disk blocks, so we do not have to issue
339 * a read. Instead we simply call vfs_bio_clrbuf(). If B_CLRBUF is
340 * not set the caller intends to overwrite the entire contents of the
341 * buffer and we don't waste time trying to clean up the contents.
343 * bp references the current indirect block. When allocating,
344 * the block must be updated.
347 pref = ffs_blkpref(ip, lbn, indirs[i].in_off, &bap[0]);
348 error = ffs_alloc(ip,
349 lbn, pref, (int)fs->fs_bsize, cred, &newb);
356 dbp->b_bio2.bio_blkno = fsbtodb(fs, nb);
357 if (flags & B_CLRBUF)
359 if (DOINGSOFTDEP(vp))
360 softdep_setup_allocindir_page(ip, lbn, bp,
361 indirs[i].in_off, nb, 0, dbp);
362 bap[indirs[i].in_off] = nb;
364 * If required, write synchronously, otherwise use
367 if (flags & B_SYNC) {
370 if (bp->b_bufsize == fs->fs_bsize)
371 bp->b_flags |= B_CLUSTEROK;
380 * At this point all related indirect blocks have been allocated
381 * if necessary and released. bp is no longer valid. dbp holds
382 * our getblk()'d data block.
384 * XXX we previously performed a cluster_read operation here.
386 if (flags & B_CLRBUF) {
388 * If B_CLRBUF is set we must validate the invalid portions
389 * of the buffer. This typically requires a read-before-
390 * write. The strategy call will fill in bio_blkno in that
393 * If we hit this case we do a cluster read if possible
394 * since nearby data blocks are likely to be accessed soon
397 if ((dbp->b_flags & B_CACHE) == 0) {
399 seqcount = (flags & B_SEQMASK) >> B_SEQSHIFT;
401 (vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0) {
402 error = cluster_read(vp, ip->i_size, lbn,
404 MAXBSIZE, seqcount, &dbp);
406 error = bread(vp, lbn, (int)fs->fs_bsize, &dbp);
411 dbp->b_bio2.bio_blkno = fsbtodb(fs, nb);
415 * If B_CLRBUF is not set the caller intends to overwrite
416 * the entire contents of the buffer. We can simply set
417 * bio_blkno and we are done.
419 dbp->b_bio2.bio_blkno = fsbtodb(fs, nb);
425 * If we have failed part way through block allocation, we
426 * have to deallocate any indirect blocks that we have allocated.
427 * We have to fsync the file before we start to get rid of all
428 * of its dependencies so that we do not leave them dangling.
429 * We have to sync it at the end so that the soft updates code
430 * does not find any untracked changes. Although this is really
431 * slow, running out of disk space is not expected to be a common
432 * occurence. The error return from fsync is ignored as we already
433 * have an error to return to the user.
435 (void) VOP_FSYNC(vp, MNT_WAIT, td);
436 for (deallocated = 0, blkp = allociblk; blkp < allocblk; blkp++) {
437 ffs_blkfree(ip, *blkp, fs->fs_bsize);
438 deallocated += fs->fs_bsize;
440 if (allocib != NULL) {
442 } else if (unwindidx >= 0) {
445 r = bread(vp, indirs[unwindidx].in_lbn, (int)fs->fs_bsize, &bp);
447 panic("Could not unwind indirect block, error %d", r);
450 bap = (ufs_daddr_t *)bp->b_data;
451 bap[indirs[unwindidx].in_off] = 0;
452 if (flags & B_SYNC) {
455 if (bp->b_bufsize == fs->fs_bsize)
456 bp->b_flags |= B_CLUSTEROK;
464 * Restore user's disk quota because allocation failed.
466 (void) chkdq(ip, (long)-btodb(deallocated), cred, FORCE);
468 ip->i_blocks -= btodb(deallocated);
469 ip->i_flag |= IN_CHANGE | IN_UPDATE;
471 (void) VOP_FSYNC(vp, MNT_WAIT, td);
474 * Cleanup the data block we getblk()'d before returning.