eattr.c

linux 内核源代码

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/gfs2_ondisk.h>
#include <linux/lm_interface.h>
#include <asm/uaccess.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "eaops.h"
#include "eattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "trans.h"
#include "util.h"

/**
 * ea_calc_size - returns the acutal number of bytes the request will take up
 *                (not counting any unstuffed data blocks)
 * @sdp:
 * @er:
 * @size:
 *
 * Returns: 1 if the EA should be stuffed
 */

static int ea_calc_size(struct gfs2_sbd *sdp, struct gfs2_ea_request *er,
			unsigned int *size)
{
	*size = GFS2_EAREQ_SIZE_STUFFED(er);
	if (*size <= sdp->sd_jbsize)
		return 1;

	*size = GFS2_EAREQ_SIZE_UNSTUFFED(sdp, er);

	return 0;
}

static int ea_check_size(struct gfs2_sbd *sdp, struct gfs2_ea_request *er)
{
	unsigned int size;

	if (er->er_data_len > GFS2_EA_MAX_DATA_LEN)
		return -ERANGE;

	ea_calc_size(sdp, er, &size);

	/* This can only happen with 512 byte blocks */
	if (size > sdp->sd_jbsize)
		return -ERANGE;

	return 0;
}

typedef int (*ea_call_t) (struct gfs2_inode *ip, struct buffer_head *bh,
			  struct gfs2_ea_header *ea,
			  struct gfs2_ea_header *prev, void *private);

static int ea_foreach_i(struct gfs2_inode *ip, struct buffer_head *bh,
			ea_call_t ea_call, void *data)
{
	struct gfs2_ea_header *ea, *prev = NULL;
	int error = 0;

	if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_EA))
		return -EIO;

	for (ea = GFS2_EA_BH2FIRST(bh);; prev = ea, ea = GFS2_EA2NEXT(ea)) {
		if (!GFS2_EA_REC_LEN(ea))
			goto fail;
		if (!(bh->b_data <= (char *)ea && (char *)GFS2_EA2NEXT(ea) <=
						  bh->b_data + bh->b_size))
			goto fail;
		if (!GFS2_EATYPE_VALID(ea->ea_type))
			goto fail;

		error = ea_call(ip, bh, ea, prev, data);
		if (error)
			return error;

		if (GFS2_EA_IS_LAST(ea)) {
			if ((char *)GFS2_EA2NEXT(ea) !=
			    bh->b_data + bh->b_size)
				goto fail;
			break;
		}
	}

	return error;

fail:
	gfs2_consist_inode(ip);
	return -EIO;
}

static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
{
	struct buffer_head *bh, *eabh;
	__be64 *eablk, *end;
	int error;

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

	if (!(ip->i_di.di_flags & GFS2_DIF_EA_INDIRECT)) {
		error = ea_foreach_i(ip, bh, ea_call, data);
		goto out;
	}

	if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_IN)) {
		error = -EIO;
		goto out;
	}

	eablk = (__be64 *)(bh->b_data + sizeof(struct gfs2_meta_header));
	end = eablk + GFS2_SB(&ip->i_inode)->sd_inptrs;

	for (; eablk < end; eablk++) {
		u64 bn;

		if (!*eablk)
			break;
		bn = be64_to_cpu(*eablk);

		error = gfs2_meta_read(ip->i_gl, bn, DIO_WAIT, &eabh);
		if (error)
			break;
		error = ea_foreach_i(ip, eabh, ea_call, data);
		brelse(eabh);
		if (error)
			break;
	}
out:
	brelse(bh);
	return error;
}

struct ea_find {
	struct gfs2_ea_request *ef_er;
	struct gfs2_ea_location *ef_el;
};

static int ea_find_i(struct gfs2_inode *ip, struct buffer_head *bh,
		     struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
		     void *private)
{
	struct ea_find *ef = private;
	struct gfs2_ea_request *er = ef->ef_er;

	if (ea->ea_type == GFS2_EATYPE_UNUSED)
		return 0;

	if (ea->ea_type == er->er_type) {
		if (ea->ea_name_len == er->er_name_len &&
		    !memcmp(GFS2_EA2NAME(ea), er->er_name, ea->ea_name_len)) {
			struct gfs2_ea_location *el = ef->ef_el;
			get_bh(bh);
			el->el_bh = bh;
			el->el_ea = ea;
			el->el_prev = prev;
			return 1;
		}
	}

	return 0;
}

int gfs2_ea_find(struct gfs2_inode *ip, struct gfs2_ea_request *er,
		 struct gfs2_ea_location *el)
{
	struct ea_find ef;
	int error;

	ef.ef_er = er;
	ef.ef_el = el;

	memset(el, 0, sizeof(struct gfs2_ea_location));

	error = ea_foreach(ip, ea_find_i, &ef);
	if (error > 0)
		return 0;

	return error;
}

/**
 * ea_dealloc_unstuffed -
 * @ip:
 * @bh:
 * @ea:
 * @prev:
 * @private:
 *
 * Take advantage of the fact that all unstuffed blocks are
 * allocated from the same RG.  But watch, this may not always
 * be true.
 *
 * Returns: errno
 */

static int ea_dealloc_unstuffed(struct gfs2_inode *ip, struct buffer_head *bh,
				struct gfs2_ea_header *ea,
				struct gfs2_ea_header *prev, void *private)
{
	int *leave = private;
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct gfs2_rgrpd *rgd;
	struct gfs2_holder rg_gh;
	struct buffer_head *dibh;
	__be64 *dataptrs;
	u64 bn = 0;
	u64 bstart = 0;
	unsigned int blen = 0;
	unsigned int blks = 0;
	unsigned int x;
	int error;

	if (GFS2_EA_IS_STUFFED(ea))
		return 0;

	dataptrs = GFS2_EA2DATAPTRS(ea);
	for (x = 0; x < ea->ea_num_ptrs; x++, dataptrs++) {
		if (*dataptrs) {
			blks++;
			bn = be64_to_cpu(*dataptrs);
		}
	}
	if (!blks)
		return 0;

	rgd = gfs2_blk2rgrpd(sdp, bn);
	if (!rgd) {
		gfs2_consist_inode(ip);
		return -EIO;
	}

	error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE, 0, &rg_gh);
	if (error)
		return error;

	error = gfs2_trans_begin(sdp, rgd->rd_length + RES_DINODE +
				 RES_EATTR + RES_STATFS + RES_QUOTA, blks);
	if (error)
		goto out_gunlock;

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

	dataptrs = GFS2_EA2DATAPTRS(ea);
	for (x = 0; x < ea->ea_num_ptrs; x++, dataptrs++) {
		if (!*dataptrs)
			break;
		bn = be64_to_cpu(*dataptrs);

		if (bstart + blen == bn)
			blen++;
		else {
			if (bstart)
				gfs2_free_meta(ip, bstart, blen);
			bstart = bn;
			blen = 1;
		}

		*dataptrs = 0;
		if (!ip->i_di.di_blocks)
			gfs2_consist_inode(ip);
		ip->i_di.di_blocks--;
		gfs2_set_inode_blocks(&ip->i_inode);
	}
	if (bstart)
		gfs2_free_meta(ip, bstart, blen);

	if (prev && !leave) {
		u32 len;

		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;
	} else {
		ea->ea_type = GFS2_EATYPE_UNUSED;
		ea->ea_num_ptrs = 0;
	}

	error = gfs2_meta_inode_buffer(ip, &dibh);
	if (!error) {
		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);
	}

	gfs2_trans_end(sdp);

out_gunlock:
	gfs2_glock_dq_uninit(&rg_gh);
	return error;
}

static int ea_remove_unstuffed(struct gfs2_inode *ip, struct buffer_head *bh,
			       struct gfs2_ea_header *ea,
			       struct gfs2_ea_header *prev, int leave)
{
	struct gfs2_alloc *al;
	int error;

	al = gfs2_alloc_get(ip);

	error = gfs2_quota_hold(ip, NO_QUOTA_CHANGE, NO_QUOTA_CHANGE);
	if (error)
		goto out_alloc;

	error = gfs2_rindex_hold(GFS2_SB(&ip->i_inode), &al->al_ri_gh);
	if (error)
		goto out_quota;

	error = ea_dealloc_unstuffed(ip, bh, ea, prev, (leave) ? &error : NULL);

	gfs2_glock_dq_uninit(&al->al_ri_gh);

out_quota:
	gfs2_quota_unhold(ip);
out_alloc:
	gfs2_alloc_put(ip);
	return error;
}

struct ea_list {
	struct gfs2_ea_request *ei_er;
	unsigned int ei_size;
};

static int ea_list_i(struct gfs2_inode *ip, struct buffer_head *bh,
		     struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
		     void *private)
{
	struct ea_list *ei = private;
	struct gfs2_ea_request *er = ei->ei_er;
	unsigned int ea_size = gfs2_ea_strlen(ea);

	if (ea->ea_type == GFS2_EATYPE_UNUSED)
		return 0;

	if (er->er_data_len) {
		char *prefix = NULL;
		unsigned int l = 0;
		char c = 0;

		if (ei->ei_size + ea_size > er->er_data_len)
			return -ERANGE;

		switch (ea->ea_type) {
		case GFS2_EATYPE_USR:
			prefix = "user.";
			l = 5;
			break;
		case GFS2_EATYPE_SYS:
			prefix = "system.";
			l = 7;
			break;
		case GFS2_EATYPE_SECURITY:
			prefix = "security.";
			l = 9;
			break;
		}

		BUG_ON(l == 0);

		memcpy(er->er_data + ei->ei_size, prefix, l);
		memcpy(er->er_data + ei->ei_size + l, GFS2_EA2NAME(ea),
		       ea->ea_name_len);
		memcpy(er->er_data + ei->ei_size + ea_size - 1, &c, 1);
	}

	ei->ei_size += ea_size;

	return 0;
}

/**
 * gfs2_ea_list -
 * @ip:
 * @er:
 *
 * Returns: actual size of data on success, -errno on error
 */

int gfs2_ea_list(struct gfs2_inode *ip, struct gfs2_ea_request *er)
{
	struct gfs2_holder i_gh;
	int error;

	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;

	if (ip->i_di.di_eattr) {
		struct ea_list ei = { .ei_er = er, .ei_size = 0 };

		error = ea_foreach(ip, ea_list_i, &ei);
		if (!error)
			error = ei.ei_size;
	}

	gfs2_glock_dq_uninit(&i_gh);

	return error;
}

/**
 * ea_get_unstuffed - actually copies the unstuffed data into the
 *                    request buffer
 * @ip: The GFS2 inode
 * @ea: The extended attribute header structure
 * @data: The data to be copied
 *
 * Returns: errno
 */

static int ea_get_unstuffed(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
			    char *data)
{
	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
	struct buffer_head **bh;
	unsigned int amount = GFS2_EA_DATA_LEN(ea);
	unsigned int nptrs = DIV_ROUND_UP(amount, sdp->sd_jbsize);
	__be64 *dataptrs = GFS2_EA2DATAPTRS(ea);
	unsigned int x;
	int error = 0;

	bh = kcalloc(nptrs, sizeof(struct buffer_head *), GFP_KERNEL);
	if (!bh)
		return -ENOMEM;

	for (x = 0; x < nptrs; x++) {
		error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0,
				       bh + x);
		if (error) {
			while (x--)
				brelse(bh[x]);
			goto out;
		}
		dataptrs++;
	}

	for (x = 0; x < nptrs; x++) {
		error = gfs2_meta_wait(sdp, bh[x]);
		if (error) {
			for (; x < nptrs; x++)
				brelse(bh[x]);
			goto out;
		}
		if (gfs2_metatype_check(sdp, bh[x], GFS2_METATYPE_ED)) {
			for (; x < nptrs; x++)
				brelse(bh[x]);
			error = -EIO;
			goto out;
		}

		memcpy(data, bh[x]->b_data + sizeof(struct gfs2_meta_header),
		       (sdp->sd_jbsize > amount) ? amount : sdp->sd_jbsize);

		amount -= sdp->sd_jbsize;
		data += sdp->sd_jbsize;

		brelse(bh[x]);
	}

out:
	kfree(bh);
	return error;
}

int gfs2_ea_get_copy(struct gfs2_inode *ip, struct gfs2_ea_location *el,
		     char *data)
{
	if (GFS2_EA_IS_STUFFED(el->el_ea)) {
		memcpy(data, GFS2_EA2DATA(el->el_ea), GFS2_EA_DATA_LEN(el->el_ea));
		return 0;
	} else
		return ea_get_unstuffed(ip, el->el_ea, data);
}