eattr.c

linux 内核源代码

/**
 * gfs2_ea_get_i -
 * @ip: The GFS2 inode
 * @er: The request structure
 *
 * Returns: actual size of data on success, -errno on error
 */

int gfs2_ea_get_i(struct gfs2_inode *ip, struct gfs2_ea_request *er)
{
	struct gfs2_ea_location el;
	int error;

	if (!ip->i_di.di_eattr)
		return -ENODATA;

	error = gfs2_ea_find(ip, er, &el);
	if (error)
		return error;
	if (!el.el_ea)
		return -ENODATA;

	if (er->er_data_len) {
		if (GFS2_EA_DATA_LEN(el.el_ea) > er->er_data_len)
			error =  -ERANGE;
		else
			error = gfs2_ea_get_copy(ip, &el, er->er_data);
	}
	if (!error)
		error = GFS2_EA_DATA_LEN(el.el_ea);

	brelse(el.el_bh);

	return error;
}

/**
 * gfs2_ea_get -
 * @ip: The GFS2 inode
 * @er: The request structure
 *
 * Returns: actual size of data on success, -errno on error
 */

int gfs2_ea_get(struct gfs2_inode *ip, struct gfs2_ea_request *er)
{
	struct gfs2_holder i_gh;
	int error;

	if (!er->er_name_len ||
	    er->er_name_len > GFS2_EA_MAX_NAME_LEN)
		return -EINVAL;
	if (!er->er_data || !er->er_data_len) {
		er->er_data = NULL;
		er->er_data_len = 0;
	}

	error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
	if (error)
		return error;

	error = gfs2_ea_ops[er->er_type]->eo_get(ip, er);

	gfs2_glock_dq_uninit(&i_gh);

	return error;
}

/**
 * ea_alloc_blk - allocates a new block for extended attributes.
 * @ip: A pointer to the inode that's getting extended attributes
 * @bhp: Pointer to pointer to a struct buffer_head
 *
 * Returns: errno
 */

static int ea_alloc_blk(struct gfs2_inode *ip, struct buffer_head **bhp)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct gfs2_ea_header *ea;
	u64 block;

	block = gfs2_alloc_meta(ip);

	*bhp = gfs2_meta_new(ip->i_gl, block);
	gfs2_trans_add_bh(ip->i_gl, *bhp, 1);
	gfs2_metatype_set(*bhp, GFS2_METATYPE_EA, GFS2_FORMAT_EA);
	gfs2_buffer_clear_tail(*bhp, sizeof(struct gfs2_meta_header));

	ea = GFS2_EA_BH2FIRST(*bhp);
	ea->ea_rec_len = cpu_to_be32(sdp->sd_jbsize);
	ea->ea_type = GFS2_EATYPE_UNUSED;
	ea->ea_flags = GFS2_EAFLAG_LAST;
	ea->ea_num_ptrs = 0;

	ip->i_di.di_blocks++;
	gfs2_set_inode_blocks(&ip->i_inode);

	return 0;
}

/**
 * ea_write - writes the request info to an ea, creating new blocks if
 *            necessary
 * @ip: inode that is being modified
 * @ea: the location of the new ea in a block
 * @er: the write request
 *
 * Note: does not update ea_rec_len or the GFS2_EAFLAG_LAST bin of ea_flags
 *
 * returns : errno
 */

static int ea_write(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
		    struct gfs2_ea_request *er)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);

	ea->ea_data_len = cpu_to_be32(er->er_data_len);
	ea->ea_name_len = er->er_name_len;
	ea->ea_type = er->er_type;
	ea->__pad = 0;

	memcpy(GFS2_EA2NAME(ea), er->er_name, er->er_name_len);

	if (GFS2_EAREQ_SIZE_STUFFED(er) <= sdp->sd_jbsize) {
		ea->ea_num_ptrs = 0;
		memcpy(GFS2_EA2DATA(ea), er->er_data, er->er_data_len);
	} else {
		__be64 *dataptr = GFS2_EA2DATAPTRS(ea);
		const char *data = er->er_data;
		unsigned int data_len = er->er_data_len;
		unsigned int copy;
		unsigned int x;

		ea->ea_num_ptrs = DIV_ROUND_UP(er->er_data_len, sdp->sd_jbsize);
		for (x = 0; x < ea->ea_num_ptrs; x++) {
			struct buffer_head *bh;
			u64 block;
			int mh_size = sizeof(struct gfs2_meta_header);

			block = gfs2_alloc_meta(ip);

			bh = gfs2_meta_new(ip->i_gl, block);
			gfs2_trans_add_bh(ip->i_gl, bh, 1);
			gfs2_metatype_set(bh, GFS2_METATYPE_ED, GFS2_FORMAT_ED);

			ip->i_di.di_blocks++;
			gfs2_set_inode_blocks(&ip->i_inode);

			copy = data_len > sdp->sd_jbsize ? sdp->sd_jbsize :
							   data_len;
			memcpy(bh->b_data + mh_size, data, copy);
			if (copy < sdp->sd_jbsize)
				memset(bh->b_data + mh_size + copy, 0,
				       sdp->sd_jbsize - copy);

			*dataptr++ = cpu_to_be64(bh->b_blocknr);
			data += copy;
			data_len -= copy;

			brelse(bh);
		}

		gfs2_assert_withdraw(sdp, !data_len);
	}

	return 0;
}

typedef int (*ea_skeleton_call_t) (struct gfs2_inode *ip,
				   struct gfs2_ea_request *er, void *private);

static int ea_alloc_skeleton(struct gfs2_inode *ip, struct gfs2_ea_request *er,
			     unsigned int blks,
			     ea_skeleton_call_t skeleton_call, void *private)
{
	struct gfs2_alloc *al;
	struct buffer_head *dibh;
	int error;

	al = gfs2_alloc_get(ip);

	error = gfs2_quota_lock(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
	if (error)
		goto out;

	error = gfs2_quota_check(ip, ip->i_inode.i_uid, ip->i_inode.i_gid);
	if (error)
		goto out_gunlock_q;

	al->al_requested = blks;

	error = gfs2_inplace_reserve(ip);
	if (error)
		goto out_gunlock_q;

	error = gfs2_trans_begin(GFS2_SB(&ip->i_inode),
				 blks + al->al_rgd->rd_length +
				 RES_DINODE + RES_STATFS + RES_QUOTA, 0);
	if (error)
		goto out_ipres;

	error = skeleton_call(ip, er, private);
	if (error)
		goto out_end_trans;

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (!error) {
		if (er->er_flags & GFS2_ERF_MODE) {
			gfs2_assert_withdraw(GFS2_SB(&ip->i_inode),
					    (ip->i_inode.i_mode & S_IFMT) ==
					    (er->er_mode & S_IFMT));
			ip->i_inode.i_mode = er->er_mode;
		}
		ip->i_inode.i_ctime = CURRENT_TIME;
		gfs2_trans_add_bh(ip->i_gl, dibh, 1);
		gfs2_dinode_out(ip, dibh->b_data);
		brelse(dibh);
	}

out_end_trans:
	gfs2_trans_end(GFS2_SB(&ip->i_inode));
out_ipres:
	gfs2_inplace_release(ip);
out_gunlock_q:
	gfs2_quota_unlock(ip);
out:
	gfs2_alloc_put(ip);
	return error;
}

static int ea_init_i(struct gfs2_inode *ip, struct gfs2_ea_request *er,
		     void *private)
{
	struct buffer_head *bh;
	int error;

	error = ea_alloc_blk(ip, &bh);
	if (error)
		return error;

	ip->i_di.di_eattr = bh->b_blocknr;
	error = ea_write(ip, GFS2_EA_BH2FIRST(bh), er);

	brelse(bh);

	return error;
}

/**
 * ea_init - initializes a new eattr block
 * @ip:
 * @er:
 *
 * Returns: errno
 */

static int ea_init(struct gfs2_inode *ip, struct gfs2_ea_request *er)
{
	unsigned int jbsize = GFS2_SB(&ip->i_inode)->sd_jbsize;
	unsigned int blks = 1;

	if (GFS2_EAREQ_SIZE_STUFFED(er) > jbsize)
		blks += DIV_ROUND_UP(er->er_data_len, jbsize);

	return ea_alloc_skeleton(ip, er, blks, ea_init_i, NULL);
}

static struct gfs2_ea_header *ea_split_ea(struct gfs2_ea_header *ea)
{
	u32 ea_size = GFS2_EA_SIZE(ea);
	struct gfs2_ea_header *new = (struct gfs2_ea_header *)((char *)ea +
				     ea_size);
	u32 new_size = GFS2_EA_REC_LEN(ea) - ea_size;
	int last = ea->ea_flags & GFS2_EAFLAG_LAST;

	ea->ea_rec_len = cpu_to_be32(ea_size);
	ea->ea_flags ^= last;

	new->ea_rec_len = cpu_to_be32(new_size);
	new->ea_flags = last;

	return new;
}

static void ea_set_remove_stuffed(struct gfs2_inode *ip,
				  struct gfs2_ea_location *el)
{
	struct gfs2_ea_header *ea = el->el_ea;
	struct gfs2_ea_header *prev = el->el_prev;
	u32 len;

	gfs2_trans_add_bh(ip->i_gl, el->el_bh, 1);

	if (!prev || !GFS2_EA_IS_STUFFED(ea)) {
		ea->ea_type = GFS2_EATYPE_UNUSED;
		return;
	} else if (GFS2_EA2NEXT(prev) != ea) {
		prev = GFS2_EA2NEXT(prev);
		gfs2_assert_withdraw(GFS2_SB(&ip->i_inode), GFS2_EA2NEXT(prev) == ea);
	}

	len = GFS2_EA_REC_LEN(prev) + GFS2_EA_REC_LEN(ea);
	prev->ea_rec_len = cpu_to_be32(len);

	if (GFS2_EA_IS_LAST(ea))
		prev->ea_flags |= GFS2_EAFLAG_LAST;
}

struct ea_set {
	int ea_split;

	struct gfs2_ea_request *es_er;
	struct gfs2_ea_location *es_el;

	struct buffer_head *es_bh;
	struct gfs2_ea_header *es_ea;
};

static int ea_set_simple_noalloc(struct gfs2_inode *ip, struct buffer_head *bh,
				 struct gfs2_ea_header *ea, struct ea_set *es)
{
	struct gfs2_ea_request *er = es->es_er;
	struct buffer_head *dibh;
	int error;

	error = gfs2_trans_begin(GFS2_SB(&ip->i_inode), RES_DINODE + 2 * RES_EATTR, 0);
	if (error)
		return error;

	gfs2_trans_add_bh(ip->i_gl, bh, 1);

	if (es->ea_split)
		ea = ea_split_ea(ea);

	ea_write(ip, ea, er);

	if (es->es_el)
		ea_set_remove_stuffed(ip, es->es_el);

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (error)
		goto out;

	if (er->er_flags & GFS2_ERF_MODE) {
		gfs2_assert_withdraw(GFS2_SB(&ip->i_inode),
			(ip->i_inode.i_mode & S_IFMT) == (er->er_mode & S_IFMT));
		ip->i_inode.i_mode = er->er_mode;
	}
	ip->i_inode.i_ctime = CURRENT_TIME;
	gfs2_trans_add_bh(ip->i_gl, dibh, 1);
	gfs2_dinode_out(ip, dibh->b_data);
	brelse(dibh);
out:
	gfs2_trans_end(GFS2_SB(&ip->i_inode));
	return error;
}

static int ea_set_simple_alloc(struct gfs2_inode *ip,
			       struct gfs2_ea_request *er, void *private)
{
	struct ea_set *es = private;
	struct gfs2_ea_header *ea = es->es_ea;
	int error;

	gfs2_trans_add_bh(ip->i_gl, es->es_bh, 1);

	if (es->ea_split)
		ea = ea_split_ea(ea);

	error = ea_write(ip, ea, er);
	if (error)
		return error;

	if (es->es_el)
		ea_set_remove_stuffed(ip, es->es_el);

	return 0;
}

static int ea_set_simple(struct gfs2_inode *ip, struct buffer_head *bh,
			 struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
			 void *private)
{
	struct ea_set *es = private;
	unsigned int size;
	int stuffed;
	int error;

	stuffed = ea_calc_size(GFS2_SB(&ip->i_inode), es->es_er, &size);

	if (ea->ea_type == GFS2_EATYPE_UNUSED) {
		if (GFS2_EA_REC_LEN(ea) < size)
			return 0;
		if (!GFS2_EA_IS_STUFFED(ea)) {
			error = ea_remove_unstuffed(ip, bh, ea, prev, 1);
			if (error)
				return error;
		}
		es->ea_split = 0;
	} else if (GFS2_EA_REC_LEN(ea) - GFS2_EA_SIZE(ea) >= size)
		es->ea_split = 1;
	else
		return 0;

	if (stuffed) {
		error = ea_set_simple_noalloc(ip, bh, ea, es);
		if (error)
			return error;
	} else {
		unsigned int blks;

		es->es_bh = bh;
		es->es_ea = ea;
		blks = 2 + DIV_ROUND_UP(es->es_er->er_data_len,
					GFS2_SB(&ip->i_inode)->sd_jbsize);

		error = ea_alloc_skeleton(ip, es->es_er, blks,
					  ea_set_simple_alloc, es);
		if (error)
			return error;
	}

	return 1;
}

static int ea_set_block(struct gfs2_inode *ip, struct gfs2_ea_request *er,
			void *private)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct buffer_head *indbh, *newbh;
	__be64 *eablk;
	int error;
	int mh_size = sizeof(struct gfs2_meta_header);

	if (ip->i_di.di_flags & GFS2_DIF_EA_INDIRECT) {
		__be64 *end;

		error = gfs2_meta_read(ip->i_gl, ip->i_di.di_eattr, DIO_WAIT,
				       &indbh);
		if (error)
			return error;

		if (gfs2_metatype_check(sdp, indbh, GFS2_METATYPE_IN)) {
			error = -EIO;
			goto out;
		}

		eablk = (__be64 *)(indbh->b_data + mh_size);
		end = eablk + sdp->sd_inptrs;

		for (; eablk < end; eablk++)
			if (!*eablk)
				break;

		if (eablk == end) {
			error = -ENOSPC;
			goto out;
		}

		gfs2_trans_add_bh(ip->i_gl, indbh, 1);
	} else {
		u64 blk;

		blk = gfs2_alloc_meta(ip);

		indbh = gfs2_meta_new(ip->i_gl, blk);
		gfs2_trans_add_bh(ip->i_gl, indbh, 1);
		gfs2_metatype_set(indbh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
		gfs2_buffer_clear_tail(indbh, mh_size);

		eablk = (__be64 *)(indbh->b_data + mh_size);
		*eablk = cpu_to_be64(ip->i_di.di_eattr);
		ip->i_di.di_eattr = blk;
		ip->i_di.di_flags |= GFS2_DIF_EA_INDIRECT;
		ip->i_di.di_blocks++;
		gfs2_set_inode_blocks(&ip->i_inode);

		eablk++;
	}

	error = ea_alloc_blk(ip, &newbh);
	if (error)
		goto out;

	*eablk = cpu_to_be64((u64)newbh->b_blocknr);
	error = ea_write(ip, GFS2_EA_BH2FIRST(newbh), er);
	brelse(newbh);
	if (error)
		goto out;

	if (private)
		ea_set_remove_stuffed(ip, private);

out:
	brelse(indbh);
	return error;
}

static int ea_set_i(struct gfs2_inode *ip, struct gfs2_ea_request *er,
		    struct gfs2_ea_location *el)