Esempio n. 1
0
static int
kern_sem_wait(struct thread *td, semid_t id, int tryflag,
    struct timespec *abstime)
{
	struct timespec ts1, ts2;
	struct timeval tv;
	struct file *fp;
	struct ksem *ks;
	int error;

	DP((">>> kern_sem_wait entered! pid=%d\n", (int)td->td_proc->p_pid));
	error = ksem_get(td, id, &fp);
	if (error)
		return (error);
	ks = fp->f_data;
	mtx_lock(&sem_lock);
	DP((">>> kern_sem_wait critical section entered! pid=%d\n",
	    (int)td->td_proc->p_pid));
#ifdef MAC
	error = mac_posixsem_check_wait(td->td_ucred, fp->f_cred, ks);
	if (error) {
		DP(("kern_sem_wait mac failed\n"));
		goto err;
	}
#endif
	DP(("kern_sem_wait value = %d, tryflag %d\n", ks->ks_value, tryflag));
	vfs_timestamp(&ks->ks_atime);
	while (ks->ks_value == 0) {
		ks->ks_waiters++;
		if (tryflag != 0)
			error = EAGAIN;
		else if (abstime == NULL)
			error = cv_wait_sig(&ks->ks_cv, &sem_lock);
		else {
			for (;;) {
				ts1 = *abstime;
				getnanotime(&ts2);
				timespecsub(&ts1, &ts2);
				TIMESPEC_TO_TIMEVAL(&tv, &ts1);
				if (tv.tv_sec < 0) {
					error = ETIMEDOUT;
					break;
				}
				error = cv_timedwait_sig(&ks->ks_cv,
				    &sem_lock, tvtohz(&tv));
				if (error != EWOULDBLOCK)
					break;
			}
		}
		ks->ks_waiters--;
		if (error)
			goto err;
	}
	ks->ks_value--;
	DP(("kern_sem_wait value post-decrement = %d\n", ks->ks_value));
	error = 0;
err:
	mtx_unlock(&sem_lock);
	fdrop(fp, td);
	DP(("<<< kern_sem_wait leaving, pid=%d, error = %d\n",
	    (int)td->td_proc->p_pid, error));
	return (error);
}
Esempio n. 2
0
/*
 * Allocates a new node of type 'type' inside the 'tmp' mount point, with
 * its owner set to 'uid', its group to 'gid' and its mode set to 'mode',
 * using the credentials of the process 'p'.
 *
 * If the node type is set to 'VDIR', then the parent parameter must point
 * to the parent directory of the node being created.  It may only be NULL
 * while allocating the root node.
 *
 * If the node type is set to 'VBLK' or 'VCHR', then the rdev parameter
 * specifies the device the node represents.
 *
 * If the node type is set to 'VLNK', then the parameter target specifies
 * the file name of the target file for the symbolic link that is being
 * created.
 *
 * Note that new nodes are retrieved from the available list if it has
 * items or, if it is empty, from the node pool as long as there is enough
 * space to create them.
 *
 * Returns zero on success or an appropriate error code on failure.
 */
int
tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
		 uid_t uid, gid_t gid, mode_t mode,
		 char *target, int rmajor, int rminor,
		 struct tmpfs_node **node)
{
	struct tmpfs_node *nnode;
	struct timespec ts;
	udev_t rdev;

	KKASSERT(IFF(type == VLNK, target != NULL));
	KKASSERT(IFF(type == VBLK || type == VCHR, rmajor != VNOVAL));

	if (tmp->tm_nodes_inuse >= tmp->tm_nodes_max)
		return (ENOSPC);

	nnode = objcache_get(tmp->tm_node_pool, M_WAITOK | M_NULLOK);
	if (nnode == NULL)
		return (ENOSPC);

	/* Generic initialization. */
	nnode->tn_type = type;
	vfs_timestamp(&ts);
	nnode->tn_ctime = nnode->tn_mtime = nnode->tn_atime
		= ts.tv_sec;
	nnode->tn_ctimensec = nnode->tn_mtimensec = nnode->tn_atimensec
		= ts.tv_nsec;
	nnode->tn_uid = uid;
	nnode->tn_gid = gid;
	nnode->tn_mode = mode;
	nnode->tn_id = tmpfs_fetch_ino(tmp);
	nnode->tn_advlock.init_done = 0;
	KKASSERT(nnode->tn_links == 0);

	/* Type-specific initialization. */
	switch (nnode->tn_type) {
	case VBLK:
	case VCHR:
		rdev = makeudev(rmajor, rminor);
		if (rdev == NOUDEV) {
			objcache_put(tmp->tm_node_pool, nnode);
			return(EINVAL);
		}
		nnode->tn_rdev = rdev;
		break;

	case VDIR:
		RB_INIT(&nnode->tn_dir.tn_dirtree);
		RB_INIT(&nnode->tn_dir.tn_cookietree);
		nnode->tn_size = 0;
		break;

	case VFIFO:
		/* FALLTHROUGH */
	case VSOCK:
		break;

	case VLNK:
		nnode->tn_size = strlen(target);
		nnode->tn_link = kmalloc(nnode->tn_size + 1, tmp->tm_name_zone,
					 M_WAITOK | M_NULLOK);
		if (nnode->tn_link == NULL) {
			objcache_put(tmp->tm_node_pool, nnode);
			return (ENOSPC);
		}
		bcopy(target, nnode->tn_link, nnode->tn_size);
		nnode->tn_link[nnode->tn_size] = '\0';
		break;

	case VREG:
		nnode->tn_reg.tn_aobj = swap_pager_alloc(NULL, 0,
							 VM_PROT_DEFAULT, 0);
		nnode->tn_reg.tn_aobj_pages = 0;
		nnode->tn_size = 0;
		vm_object_set_flag(nnode->tn_reg.tn_aobj, OBJ_NOPAGEIN);
		break;

	default:
		panic("tmpfs_alloc_node: type %p %d", nnode, (int)nnode->tn_type);
	}

	TMPFS_NODE_LOCK(nnode);
	TMPFS_LOCK(tmp);
	LIST_INSERT_HEAD(&tmp->tm_nodes_used, nnode, tn_entries);
	tmp->tm_nodes_inuse++;
	TMPFS_UNLOCK(tmp);
	TMPFS_NODE_UNLOCK(nnode);

	*node = nnode;
	return 0;
}
Esempio n. 3
0
/*
 * Write a directory entry after a call to namei, using the parameters
 * that ulfs_lookup left in nameidata and in the ulfs_lookup_results.
 *
 * DVP is the directory to be updated. It must be locked.
 * ULR is the ulfs_lookup_results structure from the final lookup step.
 * TVP is not used. (XXX: why is it here? remove it)
 * DIRP is the new directory entry contents.
 * CNP is the componentname from the final lookup step.
 * NEWDIRBP is not used and (XXX) should be removed. The previous
 * comment here said it was used by the now-removed softupdates code.
 *
 * The link count of the target inode is *not* incremented; the
 * caller does that.
 *
 * If ulr->ulr_count is 0, ulfs_lookup did not find space to insert the
 * directory entry. ulr_offset, which is the place to put the entry,
 * should be on a block boundary (and should be at the end of the
 * directory AFAIK) and a fresh block is allocated to put the new
 * directory entry in.
 *
 * If ulr->ulr_count is not zero, ulfs_lookup found a slot to insert
 * the entry into. This slot ranges from ulr_offset to ulr_offset +
 * ulr_count. However, this slot may already be partially populated
 * requiring compaction. See notes below.
 *
 * Furthermore, if ulr_count is not zero and ulr_endoff is not the
 * same as i_size, the directory is truncated to size ulr_endoff.
 */
int
ulfs_direnter(struct vnode *dvp, const struct ulfs_lookup_results *ulr,
    struct vnode *tvp, struct lfs_direct *dirp,
    struct componentname *cnp, struct buf *newdirbp)
{
	kauth_cred_t cr;
	int newentrysize;
	struct inode *dp;
	struct buf *bp;
	u_int dsize;
	struct lfs_direct *ep, *nep;
	int error, ret, lfs_blkoff, loc, spacefree;
	char *dirbuf;
	struct timespec ts;
	struct ulfsmount *ump = VFSTOULFS(dvp->v_mount);
	struct lfs *fs = ump->um_lfs;
	const int needswap = ULFS_MPNEEDSWAP(fs);
	int dirblksiz = fs->um_dirblksiz;

	error = 0;
	cr = cnp->cn_cred;

	dp = VTOI(dvp);
	newentrysize = LFS_DIRSIZ(0, dirp, 0);

	if (ulr->ulr_count == 0) {
		/*
		 * If ulr_count is 0, then namei could find no
		 * space in the directory. Here, ulr_offset will
		 * be on a directory block boundary and we will write the
		 * new entry into a fresh block.
		 */
		if (ulr->ulr_offset & (dirblksiz - 1))
			panic("ulfs_direnter: newblk");
		if ((error = lfs_balloc(dvp, (off_t)ulr->ulr_offset, dirblksiz,
		    cr, B_CLRBUF | B_SYNC, &bp)) != 0) {
			return (error);
		}
		dp->i_size = ulr->ulr_offset + dirblksiz;
		DIP_ASSIGN(dp, size, dp->i_size);
		dp->i_flag |= IN_CHANGE | IN_UPDATE;
		uvm_vnp_setsize(dvp, dp->i_size);
		dirp->d_reclen = ulfs_rw16(dirblksiz, needswap);
		dirp->d_ino = ulfs_rw32(dirp->d_ino, needswap);
		if (FSFMT(dvp)) {
#if (BYTE_ORDER == LITTLE_ENDIAN)
			if (needswap == 0) {
#else
			if (needswap != 0) {
#endif
				u_char tmp = dirp->d_namlen;
				dirp->d_namlen = dirp->d_type;
				dirp->d_type = tmp;
			}
		}
		lfs_blkoff = ulr->ulr_offset & (ump->um_mountp->mnt_stat.f_iosize - 1);
		memcpy((char *)bp->b_data + lfs_blkoff, dirp, newentrysize);
#ifdef LFS_DIRHASH
		if (dp->i_dirhash != NULL) {
			ulfsdirhash_newblk(dp, ulr->ulr_offset);
			ulfsdirhash_add(dp, dirp, ulr->ulr_offset);
			ulfsdirhash_checkblock(dp, (char *)bp->b_data + lfs_blkoff,
			    ulr->ulr_offset);
		}
#endif
		error = VOP_BWRITE(bp->b_vp, bp);
		vfs_timestamp(&ts);
		ret = lfs_update(dvp, &ts, &ts, UPDATE_DIROP);
		if (error == 0)
			return (ret);
		return (error);
	}

	/*
	 * If ulr_count is non-zero, then namei found space for the new
	 * entry in the range ulr_offset to ulr_offset + ulr_count
	 * in the directory. To use this space, we may have to compact
	 * the entries located there, by copying them together towards the
	 * beginning of the block, leaving the free space in one usable
	 * chunk at the end.
	 */

	/*
	 * Increase size of directory if entry eats into new space.
	 * This should never push the size past a new multiple of
	 * DIRBLKSIZ.
	 *
	 * N.B. - THIS IS AN ARTIFACT OF 4.2 AND SHOULD NEVER HAPPEN.
	 */
	if (ulr->ulr_offset + ulr->ulr_count > dp->i_size) {
#ifdef DIAGNOSTIC
		printf("ulfs_direnter: reached 4.2-only block, "
		       "not supposed to happen\n");
#endif
		dp->i_size = ulr->ulr_offset + ulr->ulr_count;
		DIP_ASSIGN(dp, size, dp->i_size);
		dp->i_flag |= IN_CHANGE | IN_UPDATE;
	}
	/*
	 * Get the block containing the space for the new directory entry.
	 */
	error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, &dirbuf, &bp, true);
	if (error) {
		return (error);
	}
	/*
	 * Find space for the new entry. In the simple case, the entry at
	 * offset base will have the space. If it does not, then namei
	 * arranged that compacting the region ulr_offset to
	 * ulr_offset + ulr_count would yield the space.
	 */
	ep = (struct lfs_direct *)dirbuf;
	dsize = (ep->d_ino != 0) ? LFS_DIRSIZ(FSFMT(dvp), ep, needswap) : 0;
	spacefree = ulfs_rw16(ep->d_reclen, needswap) - dsize;
	for (loc = ulfs_rw16(ep->d_reclen, needswap); loc < ulr->ulr_count; ) {
		uint16_t reclen;

		nep = (struct lfs_direct *)(dirbuf + loc);

		/* Trim the existing slot (NB: dsize may be zero). */
		ep->d_reclen = ulfs_rw16(dsize, needswap);
		ep = (struct lfs_direct *)((char *)ep + dsize);

		reclen = ulfs_rw16(nep->d_reclen, needswap);
		loc += reclen;
		if (nep->d_ino == 0) {
			/*
			 * A mid-block unused entry. Such entries are
			 * never created by the kernel, but fsck_ffs
			 * can create them (and it doesn't fix them).
			 *
			 * Add up the free space, and initialise the
			 * relocated entry since we don't memcpy it.
			 */
			spacefree += reclen;
			ep->d_ino = 0;
			dsize = 0;
			continue;
		}
		dsize = LFS_DIRSIZ(FSFMT(dvp), nep, needswap);
		spacefree += reclen - dsize;
#ifdef LFS_DIRHASH
		if (dp->i_dirhash != NULL)
			ulfsdirhash_move(dp, nep,
			    ulr->ulr_offset + ((char *)nep - dirbuf),
			    ulr->ulr_offset + ((char *)ep - dirbuf));
#endif
		memcpy((void *)ep, (void *)nep, dsize);
	}
	/*
	 * Here, `ep' points to a directory entry containing `dsize' in-use
	 * bytes followed by `spacefree' unused bytes. If ep->d_ino == 0,
	 * then the entry is completely unused (dsize == 0). The value
	 * of ep->d_reclen is always indeterminate.
	 *
	 * Update the pointer fields in the previous entry (if any),
	 * copy in the new entry, and write out the block.
	 */
	if (ep->d_ino == 0 ||
	    (ulfs_rw32(ep->d_ino, needswap) == ULFS_WINO &&
	     memcmp(ep->d_name, dirp->d_name, dirp->d_namlen) == 0)) {
		if (spacefree + dsize < newentrysize)
			panic("ulfs_direnter: compact1");
		dirp->d_reclen = spacefree + dsize;
	} else {
		if (spacefree < newentrysize)
			panic("ulfs_direnter: compact2");
		dirp->d_reclen = spacefree;
		ep->d_reclen = ulfs_rw16(dsize, needswap);
		ep = (struct lfs_direct *)((char *)ep + dsize);
	}
	dirp->d_reclen = ulfs_rw16(dirp->d_reclen, needswap);
	dirp->d_ino = ulfs_rw32(dirp->d_ino, needswap);
	if (FSFMT(dvp)) {
#if (BYTE_ORDER == LITTLE_ENDIAN)
		if (needswap == 0) {
#else
		if (needswap != 0) {
#endif
			u_char tmp = dirp->d_namlen;
			dirp->d_namlen = dirp->d_type;
			dirp->d_type = tmp;
		}
	}
#ifdef LFS_DIRHASH
	if (dp->i_dirhash != NULL && (ep->d_ino == 0 ||
	    dirp->d_reclen == spacefree))
		ulfsdirhash_add(dp, dirp, ulr->ulr_offset + ((char *)ep - dirbuf));
#endif
	memcpy((void *)ep, (void *)dirp, (u_int)newentrysize);
#ifdef LFS_DIRHASH
	if (dp->i_dirhash != NULL)
		ulfsdirhash_checkblock(dp, dirbuf -
		    (ulr->ulr_offset & (dirblksiz - 1)),
		    ulr->ulr_offset & ~(dirblksiz - 1));
#endif
	error = VOP_BWRITE(bp->b_vp, bp);
	dp->i_flag |= IN_CHANGE | IN_UPDATE;
	/*
	 * If all went well, and the directory can be shortened, proceed
	 * with the truncation. Note that we have to unlock the inode for
	 * the entry that we just entered, as the truncation may need to
	 * lock other inodes which can lead to deadlock if we also hold a
	 * lock on the newly entered node.
	 */
	if (error == 0 && ulr->ulr_endoff && ulr->ulr_endoff < dp->i_size) {
#ifdef LFS_DIRHASH
		if (dp->i_dirhash != NULL)
			ulfsdirhash_dirtrunc(dp, ulr->ulr_endoff);
#endif
		(void) lfs_truncate(dvp, (off_t)ulr->ulr_endoff, IO_SYNC, cr);
	}
	return (error);
}

/*
 * Remove a directory entry after a call to namei, using the
 * parameters that ulfs_lookup left in nameidata and in the
 * ulfs_lookup_results.
 *
 * DVP is the directory to be updated. It must be locked.
 * ULR is the ulfs_lookup_results structure from the final lookup step.
 * IP, if not null, is the inode being unlinked.
 * FLAGS may contain DOWHITEOUT.
 * ISRMDIR is not used and (XXX) should be removed.
 *
 * If FLAGS contains DOWHITEOUT the entry is replaced with a whiteout
 * instead of being cleared.
 *
 * ulr->ulr_offset contains the position of the directory entry
 * to be removed.
 *
 * ulr->ulr_reclen contains the size of the directory entry to be
 * removed.
 *
 * ulr->ulr_count contains the size of the *previous* directory
 * entry. This allows finding it, for free space management. If
 * ulr_count is 0, the target entry is at the beginning of the
 * directory. (Does this ever happen? The first entry should be ".",
 * which should only be removed at rmdir time. Does rmdir come here
 * to clear out the "." and ".." entries? Perhaps, but I doubt it.)
 *
 * The space is marked free by adding it to the record length (not
 * name length) of the preceding entry. If the first entry becomes
 * free, it is marked free by setting the inode number to 0.
 *
 * The link count of IP is decremented. Note that this is not the
 * inverse behavior of ulfs_direnter, which does not adjust link
 * counts. Sigh.
 */
int
ulfs_dirremove(struct vnode *dvp, const struct ulfs_lookup_results *ulr,
	      struct inode *ip, int flags, int isrmdir)
{
	struct inode *dp = VTOI(dvp);
	struct lfs_direct *ep;
	struct buf *bp;
	int error;
	const int needswap = ULFS_MPNEEDSWAP(dp->i_lfs);

	if (flags & DOWHITEOUT) {
		/*
		 * Whiteout entry: set d_ino to ULFS_WINO.
		 */
		error = ulfs_blkatoff(dvp, (off_t)ulr->ulr_offset, (void *)&ep,
				     &bp, true);
		if (error)
			return (error);
		ep->d_ino = ulfs_rw32(ULFS_WINO, needswap);
		ep->d_type = LFS_DT_WHT;
		goto out;
	}

	if ((error = ulfs_blkatoff(dvp,
	    (off_t)(ulr->ulr_offset - ulr->ulr_count), (void *)&ep, &bp, true)) != 0)
		return (error);

#ifdef LFS_DIRHASH
	/*
	 * Remove the dirhash entry. This is complicated by the fact
	 * that `ep' is the previous entry when ulr_count != 0.
	 */
	if (dp->i_dirhash != NULL)
		ulfsdirhash_remove(dp, (ulr->ulr_count == 0) ? ep :
		   (struct lfs_direct *)((char *)ep +
		   ulfs_rw16(ep->d_reclen, needswap)), ulr->ulr_offset);
#endif

	if (ulr->ulr_count == 0) {
		/*
		 * First entry in block: set d_ino to zero.
		 */
		ep->d_ino = 0;
	} else {
		/*
		 * Collapse new free space into previous entry.
		 */
		ep->d_reclen =
		    ulfs_rw16(ulfs_rw16(ep->d_reclen, needswap) + ulr->ulr_reclen,
			needswap);
	}

#ifdef LFS_DIRHASH
	if (dp->i_dirhash != NULL) {
		int dirblksiz = ip->i_lfs->um_dirblksiz;
		ulfsdirhash_checkblock(dp, (char *)ep -
		    ((ulr->ulr_offset - ulr->ulr_count) & (dirblksiz - 1)),
		    ulr->ulr_offset & ~(dirblksiz - 1));
	}
#endif

out:
	if (ip) {
		ip->i_nlink--;
		DIP_ASSIGN(ip, nlink, ip->i_nlink);
		ip->i_flag |= IN_CHANGE;
	}
	/*
	 * XXX did it ever occur to anyone that it might be a good
	 * idea to restore ip->i_nlink if this fails? Or something?
	 * Currently on error return from this function the state of
	 * ip->i_nlink depends on what happened, and callers
	 * definitely do not take this into account.
	 */
	error = VOP_BWRITE(bp->b_vp, bp);
	dp->i_flag |= IN_CHANGE | IN_UPDATE;
	/*
	 * If the last named reference to a snapshot goes away,
	 * drop its snapshot reference so that it will be reclaimed
	 * when last open reference goes away.
	 */
	if (ip != 0 && (ip->i_flags & SF_SNAPSHOT) != 0 &&
	    ip->i_nlink == 0)
		ulfs_snapgone(ip);
	return (error);
}

/*
 * Rewrite an existing directory entry to point at the inode supplied.
 *
 * DP is the directory to update.
 * OFFSET is the position of the entry in question. It may come
 * from ulr_offset of a ulfs_lookup_results.
 * OIP is the old inode the directory previously pointed to.
 * NEWINUM is the number of the new inode.
 * NEWTYPE is the new value for the type field of the directory entry.
 * (This is ignored if the fs doesn't support that.)
 * ISRMDIR is not used and (XXX) should be removed.
 * IFLAGS are added to DP's inode flags.
 *
 * The link count of OIP is decremented. Note that the link count of
 * the new inode is *not* incremented. Yay for symmetry.
 */
int
ulfs_dirrewrite(struct inode *dp, off_t offset,
    struct inode *oip, ino_t newinum, int newtype,
    int isrmdir, int iflags)
{
	struct buf *bp;
	struct lfs_direct *ep;
	struct vnode *vdp = ITOV(dp);
	int error;

	error = ulfs_blkatoff(vdp, offset, (void *)&ep, &bp, true);
	if (error)
		return (error);
	ep->d_ino = ulfs_rw32(newinum, ULFS_IPNEEDSWAP(dp));
	if (!FSFMT(vdp))
		ep->d_type = newtype;
	oip->i_nlink--;
	DIP_ASSIGN(oip, nlink, oip->i_nlink);
	oip->i_flag |= IN_CHANGE;
	error = VOP_BWRITE(bp->b_vp, bp);
	dp->i_flag |= iflags;
	/*
	 * If the last named reference to a snapshot goes away,
	 * drop its snapshot reference so that it will be reclaimed
	 * when last open reference goes away.
	 */
	if ((oip->i_flags & SF_SNAPSHOT) != 0 && oip->i_nlink == 0)
		ulfs_snapgone(oip);
	return (error);
}

/*
 * Check if a directory is empty or not.
 * Inode supplied must be locked.
 *
 * Using a struct lfs_dirtemplate here is not precisely
 * what we want, but better than using a struct lfs_direct.
 *
 * NB: does not handle corrupted directories.
 */
int
ulfs_dirempty(struct inode *ip, ino_t parentino, kauth_cred_t cred)
{
	doff_t off;
	struct lfs_dirtemplate dbuf;
	struct lfs_direct *dp = (struct lfs_direct *)&dbuf;
	int error, namlen;
	size_t count;
	const int needswap = ULFS_IPNEEDSWAP(ip);
#define	MINDIRSIZ (sizeof (struct lfs_dirtemplate) / 2)

	for (off = 0; off < ip->i_size;
	    off += ulfs_rw16(dp->d_reclen, needswap)) {
		error = vn_rdwr(UIO_READ, ITOV(ip), (void *)dp, MINDIRSIZ, off,
		   UIO_SYSSPACE, IO_NODELOCKED, cred, &count, NULL);
		/*
		 * Since we read MINDIRSIZ, residual must
		 * be 0 unless we're at end of file.
		 */
		if (error || count != 0)
			return (0);
		/* avoid infinite loops */
		if (dp->d_reclen == 0)
			return (0);
		/* skip empty entries */
		if (dp->d_ino == 0 || ulfs_rw32(dp->d_ino, needswap) == ULFS_WINO)
			continue;
		/* accept only "." and ".." */
#if (BYTE_ORDER == LITTLE_ENDIAN)
		if (FSFMT(ITOV(ip)) && needswap == 0)
			namlen = dp->d_type;
		else
			namlen = dp->d_namlen;
#else
		if (FSFMT(ITOV(ip)) && needswap != 0)
			namlen = dp->d_type;
		else
			namlen = dp->d_namlen;
#endif
		if (namlen > 2)
			return (0);
		if (dp->d_name[0] != '.')
			return (0);
		/*
		 * At this point namlen must be 1 or 2.
		 * 1 implies ".", 2 implies ".." if second
		 * char is also "."
		 */
		if (namlen == 1 &&
		    ulfs_rw32(dp->d_ino, needswap) == ip->i_number)
			continue;
		if (dp->d_name[1] == '.' &&
		    ulfs_rw32(dp->d_ino, needswap) == parentino)
			continue;
		return (0);
	}
	return (1);
}

#define	ULFS_DIRRABLKS 0
int ulfs_dirrablks = ULFS_DIRRABLKS;

/*
 * ulfs_blkatoff: Return buffer with the contents of block "offset" from
 * the beginning of directory "vp".  If "res" is non-NULL, fill it in with
 * a pointer to the remaining space in the directory.  If the caller intends
 * to modify the buffer returned, "modify" must be true.
 */

int
ulfs_blkatoff(struct vnode *vp, off_t offset, char **res, struct buf **bpp,
    bool modify)
{
	struct inode *ip __diagused;
	struct buf *bp;
	daddr_t lbn;
	const int dirrablks = ulfs_dirrablks;
	daddr_t *blks;
	int *blksizes;
	int run, error;
	struct mount *mp = vp->v_mount;
	const int bshift = mp->mnt_fs_bshift;
	const int bsize = 1 << bshift;
	off_t eof;

	blks = kmem_alloc((1 + dirrablks) * sizeof(daddr_t), KM_SLEEP);
	blksizes = kmem_alloc((1 + dirrablks) * sizeof(int), KM_SLEEP);
	ip = VTOI(vp);
	KASSERT(vp->v_size == ip->i_size);
	GOP_SIZE(vp, vp->v_size, &eof, 0);
	lbn = offset >> bshift;

	for (run = 0; run <= dirrablks;) {
		const off_t curoff = lbn << bshift;
		const int size = MIN(eof - curoff, bsize);

		if (size == 0) {
			break;
		}
		KASSERT(curoff < eof);
		blks[run] = lbn;
		blksizes[run] = size;
		lbn++;
		run++;
		if (size != bsize) {
			break;
		}
	}
	KASSERT(run >= 1);
	error = breadn(vp, blks[0], blksizes[0], &blks[1], &blksizes[1],
	    run - 1, NOCRED, (modify ? B_MODIFY : 0), &bp);
	if (error != 0) {
		*bpp = NULL;
		goto out;
	}
	if (res) {
		*res = (char *)bp->b_data + (offset & (bsize - 1));
	}
	*bpp = bp;

 out:
	kmem_free(blks, (1 + dirrablks) * sizeof(daddr_t));
	kmem_free(blksizes, (1 + dirrablks) * sizeof(int));
	return error;
}
Esempio n. 4
0
/*
 * Allocate an inode in the filesystem.
 * 
 */
int
ext2_valloc(struct vnode *pvp, int mode, struct ucred *cred, struct vnode **vpp)
{
	struct timespec ts;
	struct inode *pip;
	struct m_ext2fs *fs;
	struct inode *ip;
	struct ext2mount *ump;
	ino_t ino, ipref;
	int i, error, cg;
	
	*vpp = NULL;
	pip = VTOI(pvp);
	fs = pip->i_e2fs;
	ump = pip->i_ump;

	EXT2_LOCK(ump);
	if (fs->e2fs->e2fs_ficount == 0)
		goto noinodes;
	/*
	 * If it is a directory then obtain a cylinder group based on
	 * ext2_dirpref else obtain it using ino_to_cg. The preferred inode is
	 * always the next inode.
	 */
	if ((mode & IFMT) == IFDIR) {
		cg = ext2_dirpref(pip);
		if (fs->e2fs_contigdirs[cg] < 255)
			fs->e2fs_contigdirs[cg]++;
	} else {
		cg = ino_to_cg(fs, pip->i_number);
		if (fs->e2fs_contigdirs[cg] > 0)
			fs->e2fs_contigdirs[cg]--;
	}
	ipref = cg * fs->e2fs->e2fs_ipg + 1;
	ino = (ino_t)ext2_hashalloc(pip, cg, (long)ipref, mode, ext2_nodealloccg);

	if (ino == 0) 
		goto noinodes;
	error = VFS_VGET(pvp->v_mount, ino, LK_EXCLUSIVE, vpp);
	if (error) {
		ext2_vfree(pvp, ino, mode);
		return (error);
	}
	ip = VTOI(*vpp);

	/*
	 * The question is whether using VGET was such good idea at all:
	 * Linux doesn't read the old inode in when it is allocating a
	 * new one. I will set at least i_size and i_blocks to zero.
	 */
	ip->i_flag = 0;
	ip->i_size = 0;
	ip->i_blocks = 0;
	ip->i_mode = 0;
	ip->i_flags = 0;
	/* now we want to make sure that the block pointers are zeroed out */
	for (i = 0; i < NDADDR; i++)
		ip->i_db[i] = 0;
	for (i = 0; i < NIADDR; i++)
		ip->i_ib[i] = 0;

	/*
	 * Set up a new generation number for this inode.
	 */
	ip->i_gen = arc4random();

	vfs_timestamp(&ts);
	ip->i_birthtime = ts.tv_sec;
	ip->i_birthnsec = ts.tv_nsec;

/*
printf("ext2_valloc: allocated inode %d\n", ino);
*/
	return (0);
noinodes:
	EXT2_UNLOCK(ump);
	ext2_fserr(fs, cred->cr_uid, "out of inodes");
	uprintf("\n%s: create/symlink failed, no inodes free\n", fs->e2fs_fsmnt);
	return (ENOSPC);
}