xfs_attr_leaf.c

linux 内核源代码

		 */
		map = &hdr->freemap[smallest];
		if (be16_to_cpu(map->size) < entsize) {
			map->base = cpu_to_be16(be16_to_cpu(entry->nameidx));
			map->size = cpu_to_be16(entsize);
		}
	}

	/*
	 * Did we remove the first entry?
	 */
	if (be16_to_cpu(entry->nameidx) == be16_to_cpu(hdr->firstused))
		smallest = 1;
	else
		smallest = 0;

	/*
	 * Compress the remaining entries and zero out the removed stuff.
	 */
	memset(XFS_ATTR_LEAF_NAME(leaf, args->index), 0, entsize);
	be16_add(&hdr->usedbytes, -entsize);
	xfs_da_log_buf(args->trans, bp,
	     XFS_DA_LOGRANGE(leaf, XFS_ATTR_LEAF_NAME(leaf, args->index),
				   entsize));

	tmp = (be16_to_cpu(hdr->count) - args->index)
					* sizeof(xfs_attr_leaf_entry_t);
	memmove((char *)entry, (char *)(entry+1), tmp);
	be16_add(&hdr->count, -1);
	xfs_da_log_buf(args->trans, bp,
	    XFS_DA_LOGRANGE(leaf, entry, tmp + sizeof(*entry)));
	entry = &leaf->entries[be16_to_cpu(hdr->count)];
	memset((char *)entry, 0, sizeof(xfs_attr_leaf_entry_t));

	/*
	 * If we removed the first entry, re-find the first used byte
	 * in the name area.  Note that if the entry was the "firstused",
	 * then we don't have a "hole" in our block resulting from
	 * removing the name.
	 */
	if (smallest) {
		tmp = XFS_LBSIZE(mp);
		entry = &leaf->entries[0];
		for (i = be16_to_cpu(hdr->count)-1; i >= 0; entry++, i--) {
			ASSERT(be16_to_cpu(entry->nameidx) >=
			       be16_to_cpu(hdr->firstused));
			ASSERT(be16_to_cpu(entry->nameidx) < XFS_LBSIZE(mp));

			if (be16_to_cpu(entry->nameidx) < tmp)
				tmp = be16_to_cpu(entry->nameidx);
		}
		hdr->firstused = cpu_to_be16(tmp);
		if (!hdr->firstused) {
			hdr->firstused = cpu_to_be16(
					tmp - XFS_ATTR_LEAF_NAME_ALIGN);
		}
	} else {
		hdr->holes = 1;		/* mark as needing compaction */
	}
	xfs_da_log_buf(args->trans, bp,
			  XFS_DA_LOGRANGE(leaf, hdr, sizeof(*hdr)));

	/*
	 * Check if leaf is less than 50% full, caller may want to
	 * "join" the leaf with a sibling if so.
	 */
	tmp  = sizeof(xfs_attr_leaf_hdr_t);
	tmp += be16_to_cpu(leaf->hdr.count) * sizeof(xfs_attr_leaf_entry_t);
	tmp += be16_to_cpu(leaf->hdr.usedbytes);
	return(tmp < mp->m_attr_magicpct); /* leaf is < 37% full */
}

/*
 * Move all the attribute list entries from drop_leaf into save_leaf.
 */
void
xfs_attr_leaf_unbalance(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk,
				       xfs_da_state_blk_t *save_blk)
{
	xfs_attr_leafblock_t *drop_leaf, *save_leaf, *tmp_leaf;
	xfs_attr_leaf_hdr_t *drop_hdr, *save_hdr, *tmp_hdr;
	xfs_mount_t *mp;
	char *tmpbuffer;

	/*
	 * Set up environment.
	 */
	mp = state->mp;
	ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC);
	ASSERT(save_blk->magic == XFS_ATTR_LEAF_MAGIC);
	drop_leaf = drop_blk->bp->data;
	save_leaf = save_blk->bp->data;
	ASSERT(be16_to_cpu(drop_leaf->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	ASSERT(be16_to_cpu(save_leaf->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	drop_hdr = &drop_leaf->hdr;
	save_hdr = &save_leaf->hdr;

	/*
	 * Save last hashval from dying block for later Btree fixup.
	 */
	drop_blk->hashval = be32_to_cpu(
		drop_leaf->entries[be16_to_cpu(drop_leaf->hdr.count)-1].hashval);

	/*
	 * Check if we need a temp buffer, or can we do it in place.
	 * Note that we don't check "leaf" for holes because we will
	 * always be dropping it, toosmall() decided that for us already.
	 */
	if (save_hdr->holes == 0) {
		/*
		 * dest leaf has no holes, so we add there.  May need
		 * to make some room in the entry array.
		 */
		if (xfs_attr_leaf_order(save_blk->bp, drop_blk->bp)) {
			xfs_attr_leaf_moveents(drop_leaf, 0, save_leaf, 0,
			     be16_to_cpu(drop_hdr->count), mp);
		} else {
			xfs_attr_leaf_moveents(drop_leaf, 0, save_leaf,
				  be16_to_cpu(save_hdr->count),
				  be16_to_cpu(drop_hdr->count), mp);
		}
	} else {
		/*
		 * Destination has holes, so we make a temporary copy
		 * of the leaf and add them both to that.
		 */
		tmpbuffer = kmem_alloc(state->blocksize, KM_SLEEP);
		ASSERT(tmpbuffer != NULL);
		memset(tmpbuffer, 0, state->blocksize);
		tmp_leaf = (xfs_attr_leafblock_t *)tmpbuffer;
		tmp_hdr = &tmp_leaf->hdr;
		tmp_hdr->info = save_hdr->info;	/* struct copy */
		tmp_hdr->count = 0;
		tmp_hdr->firstused = cpu_to_be16(state->blocksize);
		if (!tmp_hdr->firstused) {
			tmp_hdr->firstused = cpu_to_be16(
				state->blocksize - XFS_ATTR_LEAF_NAME_ALIGN);
		}
		tmp_hdr->usedbytes = 0;
		if (xfs_attr_leaf_order(save_blk->bp, drop_blk->bp)) {
			xfs_attr_leaf_moveents(drop_leaf, 0, tmp_leaf, 0,
				be16_to_cpu(drop_hdr->count), mp);
			xfs_attr_leaf_moveents(save_leaf, 0, tmp_leaf,
				  be16_to_cpu(tmp_leaf->hdr.count),
				  be16_to_cpu(save_hdr->count), mp);
		} else {
			xfs_attr_leaf_moveents(save_leaf, 0, tmp_leaf, 0,
				be16_to_cpu(save_hdr->count), mp);
			xfs_attr_leaf_moveents(drop_leaf, 0, tmp_leaf,
				be16_to_cpu(tmp_leaf->hdr.count),
				be16_to_cpu(drop_hdr->count), mp);
		}
		memcpy((char *)save_leaf, (char *)tmp_leaf, state->blocksize);
		kmem_free(tmpbuffer, state->blocksize);
	}

	xfs_da_log_buf(state->args->trans, save_blk->bp, 0,
					   state->blocksize - 1);

	/*
	 * Copy out last hashval in each block for B-tree code.
	 */
	save_blk->hashval = be32_to_cpu(
		save_leaf->entries[be16_to_cpu(save_leaf->hdr.count)-1].hashval);
}

/*========================================================================
 * Routines used for finding things in the Btree.
 *========================================================================*/

/*
 * Look up a name in a leaf attribute list structure.
 * This is the internal routine, it uses the caller's buffer.
 *
 * Note that duplicate keys are allowed, but only check within the
 * current leaf node.  The Btree code must check in adjacent leaf nodes.
 *
 * Return in args->index the index into the entry[] array of either
 * the found entry, or where the entry should have been (insert before
 * that entry).
 *
 * Don't change the args->value unless we find the attribute.
 */
int
xfs_attr_leaf_lookup_int(xfs_dabuf_t *bp, xfs_da_args_t *args)
{
	xfs_attr_leafblock_t *leaf;
	xfs_attr_leaf_entry_t *entry;
	xfs_attr_leaf_name_local_t *name_loc;
	xfs_attr_leaf_name_remote_t *name_rmt;
	int probe, span;
	xfs_dahash_t hashval;

	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	ASSERT(be16_to_cpu(leaf->hdr.count)
					< (XFS_LBSIZE(args->dp->i_mount)/8));

	/*
	 * Binary search.  (note: small blocks will skip this loop)
	 */
	hashval = args->hashval;
	probe = span = be16_to_cpu(leaf->hdr.count) / 2;
	for (entry = &leaf->entries[probe]; span > 4;
		   entry = &leaf->entries[probe]) {
		span /= 2;
		if (be32_to_cpu(entry->hashval) < hashval)
			probe += span;
		else if (be32_to_cpu(entry->hashval) > hashval)
			probe -= span;
		else
			break;
	}
	ASSERT((probe >= 0) &&
	       (!leaf->hdr.count
	       || (probe < be16_to_cpu(leaf->hdr.count))));
	ASSERT((span <= 4) || (be32_to_cpu(entry->hashval) == hashval));

	/*
	 * Since we may have duplicate hashval's, find the first matching
	 * hashval in the leaf.
	 */
	while ((probe > 0) && (be32_to_cpu(entry->hashval) >= hashval)) {
		entry--;
		probe--;
	}
	while ((probe < be16_to_cpu(leaf->hdr.count)) &&
	       (be32_to_cpu(entry->hashval) < hashval)) {
		entry++;
		probe++;
	}
	if ((probe == be16_to_cpu(leaf->hdr.count)) ||
	    (be32_to_cpu(entry->hashval) != hashval)) {
		args->index = probe;
		return(XFS_ERROR(ENOATTR));
	}

	/*
	 * Duplicate keys may be present, so search all of them for a match.
	 */
	for (  ; (probe < be16_to_cpu(leaf->hdr.count)) &&
			(be32_to_cpu(entry->hashval) == hashval);
			entry++, probe++) {
/*
 * GROT: Add code to remove incomplete entries.
 */
		/*
		 * If we are looking for INCOMPLETE entries, show only those.
		 * If we are looking for complete entries, show only those.
		 */
		if ((args->flags & XFS_ATTR_INCOMPLETE) !=
		    (entry->flags & XFS_ATTR_INCOMPLETE)) {
			continue;
		}
		if (entry->flags & XFS_ATTR_LOCAL) {
			name_loc = XFS_ATTR_LEAF_NAME_LOCAL(leaf, probe);
			if (name_loc->namelen != args->namelen)
				continue;
			if (memcmp(args->name, (char *)name_loc->nameval, args->namelen) != 0)
				continue;
			if (!xfs_attr_namesp_match(args->flags, entry->flags))
				continue;
			args->index = probe;
			return(XFS_ERROR(EEXIST));
		} else {
			name_rmt = XFS_ATTR_LEAF_NAME_REMOTE(leaf, probe);
			if (name_rmt->namelen != args->namelen)
				continue;
			if (memcmp(args->name, (char *)name_rmt->name,
					     args->namelen) != 0)
				continue;
			if (!xfs_attr_namesp_match(args->flags, entry->flags))
				continue;
			args->index = probe;
			args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
			args->rmtblkcnt = XFS_B_TO_FSB(args->dp->i_mount,
						   be32_to_cpu(name_rmt->valuelen));
			return(XFS_ERROR(EEXIST));
		}
	}
	args->index = probe;
	return(XFS_ERROR(ENOATTR));
}

/*
 * Get the value associated with an attribute name from a leaf attribute
 * list structure.
 */
int
xfs_attr_leaf_getvalue(xfs_dabuf_t *bp, xfs_da_args_t *args)
{
	int valuelen;
	xfs_attr_leafblock_t *leaf;
	xfs_attr_leaf_entry_t *entry;
	xfs_attr_leaf_name_local_t *name_loc;
	xfs_attr_leaf_name_remote_t *name_rmt;

	leaf = bp->data;
	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	ASSERT(be16_to_cpu(leaf->hdr.count)
					< (XFS_LBSIZE(args->dp->i_mount)/8));
	ASSERT(args->index < be16_to_cpu(leaf->hdr.count));

	entry = &leaf->entries[args->index];
	if (entry->flags & XFS_ATTR_LOCAL) {
		name_loc = XFS_ATTR_LEAF_NAME_LOCAL(leaf, args->index);
		ASSERT(name_loc->namelen == args->namelen);
		ASSERT(memcmp(args->name, name_loc->nameval, args->namelen) == 0);
		valuelen = be16_to_cpu(name_loc->valuelen);
		if (args->flags & ATTR_KERNOVAL) {
			args->valuelen = valuelen;
			return(0);
		}
		if (args->valuelen < valuelen) {
			args->valuelen = valuelen;
			return(XFS_ERROR(ERANGE));
		}
		args->valuelen = valuelen;
		memcpy(args->value, &name_loc->nameval[args->namelen], valuelen);
	} else {
		name_rmt = XFS_ATTR_LEAF_NAME_REMOTE(leaf, args->index);
		ASSERT(name_rmt->namelen == args->namelen);
		ASSERT(memcmp(args->name, name_rmt->name, args->namelen) == 0);
		valuelen = be32_to_cpu(name_rmt->valuelen);
		args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
		args->rmtblkcnt = XFS_B_TO_FSB(args->dp->i_mount, valuelen);
		if (args->flags & ATTR_KERNOVAL) {
			args->valuelen = valuelen;
			return(0);
		}
		if (args->valuelen < valuelen) {
			args->valuelen = valuelen;
			return(XFS_ERROR(ERANGE));
		}
		args->valuelen = valuelen;
	}
	return(0);
}

/*========================================================================
 * Utility routines.
 *========================================================================*/

/*
 * Move the indicated entries from one leaf to another.
 * NOTE: this routine modifies both source and destination leaves.
 */
/*ARGSUSED*/
STATIC void
xfs_attr_leaf_moveents(xfs_attr_leafblock_t *leaf_s, int start_s,
			xfs_attr_leafblock_t *leaf_d, int start_d,
			int count, xfs_mount_t *mp)
{
	xfs_attr_leaf_hdr_t *hdr_s, *hdr_d;
	xfs_attr_leaf_entry_t *entry_s, *entry_d;
	int desti, tmp, i;

	/*
	 * Check for nothing to do.
	 */
	if (count == 0)
		return;

	/*
	 * Set up environment.
	 */
	ASSERT(be16_to_cpu(leaf_s->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	ASSERT(be16_to_cpu(leaf_d->hdr.info.magic) == XFS_ATTR_LEAF_MAGIC);
	hdr_s = &leaf_s->hdr;
	hdr_d = &leaf_d->hdr;
	ASSERT((be16_to_cpu(hdr_s->count) > 0) &&
	       (be16_to_cpu(hdr_s->count) < (XFS_LBSIZE(mp)/8)));
	ASSERT(be16_to_cpu(hdr_s->firstused) >=
		((be16_to_cpu(hdr_s->count)
					* sizeof(*entry_s))+sizeof(*hdr_s)));
	ASSERT(be16_to_cpu(hdr_d->count) < (XFS_LBSIZE(mp)/8));
	ASSERT(be16_to_cpu(hdr_d->firstused) >=
		((be16_to_cpu(hdr_d->count)
					* sizeof(*entry_d))+sizeof(*hdr_d)));

	ASSERT(start_s < be16_to_cpu(hdr_s->count));
	ASSERT(start_d <= be16_to_cpu(hdr_d->count));
	ASSERT(count <= be16_to_cpu(hdr_s->count));

	/*
	 * Move the entries in the destination leaf up to make a hole?
	 */
	if (start_d < be16_to_cpu(hdr_d->count)) {
		tmp  = be16_to_cpu(hdr_d->count) - start_d;
		tmp *= sizeof(xfs_attr_leaf_entry_t);
		entry_s = &leaf_d->entries[start_d];
		entry_d = &leaf_d->entries[start_d + count];
		memmove((char *)entry_d, (char *)entry_s, tmp);
	}

	/*
	 * Copy all entry's in the same (sorted) order,
	 * but allocate attribute info packed and in sequence.
	 */
	entry_s = &leaf_s->entries[start_s];
	entry_d = &leaf_d->entries[start_d];
	desti = start_d;
	for (i = 0; i < count; entry_s++, entry_d++, desti++, i++) {
		ASSERT(be16_to_cpu(entry_s->nameidx)
				>= be16_to_cpu(hdr_s->firstused));
		tmp = xfs_attr_leaf_entsize(leaf_s, start_s + i);
#ifdef GROT
		/*
		 * Code to drop INCOMPLETE entries.  Difficult to use as we
		 * may also need to change the insertion index.  Code turned
		 * off for 6.2, should be revisited later.
		 */
		if (entry_s->flags & XFS_ATTR_INCOMPLETE) { /* skip partials? */
			memset(XFS_ATTR_LEAF_NAME(leaf_s, start_s + i), 0, tmp);
			be16_add(&hdr_s->usedbytes, -tmp);
			be16_add(&hdr_s->count, -1);
			entry_d--;	/* to compensate for ++ in loop hdr */
			desti--;
			if ((start_s + i) < offset)
				result++;	/* insertion index adjustment */
		} else {
#endif /* GROT */
			be16_add(&hdr_d->firstused, -tmp);
			/* both on-disk, don't endian flip twice */
			entry_d->hashval = entry_s->hashval;
			/* both on-disk, don't endian flip twice */
			entry_d->nameidx = hdr_d->firstused;
			entry_d->flags = entry_s->flags;
			ASSERT(be16_to_cpu(entry_d->nameidx) + tmp
							<= XFS_LBSIZE(mp));
			memmove(XFS_ATTR_LEAF_NAME(leaf_d, desti),
				XFS_ATTR_LEAF_NAME(leaf_s, start_s + i), tmp);
			ASSERT(be16_to_cpu(entry_s->nameidx) + tmp
							<= XFS_LBSIZE(mp));
			memset(XFS_ATTR_LEAF_NAME(leaf_s, start_s + i), 0, tmp);
			be16_add(&hdr_s->usedbytes, -tmp);
			be16_add(&hdr_d->usedbytes, tmp);
			be16_add(&hdr_s->count, -1);
			be16_add(&hdr_d->count, 1);
			tmp = be16_to_cpu(hdr_d->count)
						* sizeof(xfs_attr_leaf_entry_t)