dir.c

linux 内核源代码

			str.hash = be32_to_cpu(dent->de_hash);
			new = gfs2_dirent_alloc(inode, nbh, &str);
			if (IS_ERR(new)) {
				error = PTR_ERR(new);
				break;
			}

			new->de_inum = dent->de_inum; /* No endian worries */
			new->de_type = dent->de_type; /* No endian worries */
			nleaf->lf_entries = cpu_to_be16(be16_to_cpu(nleaf->lf_entries)+1);

			dirent_del(dip, obh, prev, dent);

			if (!oleaf->lf_entries)
				gfs2_consist_inode(dip);
			oleaf->lf_entries = cpu_to_be16(be16_to_cpu(oleaf->lf_entries)-1);

			if (!prev)
				prev = dent;

			moved = 1;
		} else {
			prev = dent;
		}
		dent = next;
	} while (dent);

	oleaf->lf_depth = nleaf->lf_depth;

	error = gfs2_meta_inode_buffer(dip, &dibh);
	if (!gfs2_assert_withdraw(GFS2_SB(&dip->i_inode), !error)) {
		gfs2_trans_add_bh(dip->i_gl, dibh, 1);
		dip->i_di.di_blocks++;
		gfs2_set_inode_blocks(&dip->i_inode);
		gfs2_dinode_out(dip, dibh->b_data);
		brelse(dibh);
	}

	brelse(obh);
	brelse(nbh);

	return error;

fail_lpfree:
	kfree(lp);

fail_brelse:
	brelse(obh);
	brelse(nbh);
	return error;
}

/**
 * dir_double_exhash - Double size of ExHash table
 * @dip: The GFS2 dinode
 *
 * Returns: 0 on success, error code on failure
 */

static int dir_double_exhash(struct gfs2_inode *dip)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct buffer_head *dibh;
	u32 hsize;
	u64 *buf;
	u64 *from, *to;
	u64 block;
	int x;
	int error = 0;

	hsize = 1 << dip->i_di.di_depth;
	if (hsize * sizeof(u64) != dip->i_di.di_size) {
		gfs2_consist_inode(dip);
		return -EIO;
	}

	/*  Allocate both the "from" and "to" buffers in one big chunk  */

	buf = kcalloc(3, sdp->sd_hash_bsize, GFP_KERNEL | __GFP_NOFAIL);

	for (block = dip->i_di.di_size >> sdp->sd_hash_bsize_shift; block--;) {
		error = gfs2_dir_read_data(dip, (char *)buf,
					    block * sdp->sd_hash_bsize,
					    sdp->sd_hash_bsize, 1);
		if (error != sdp->sd_hash_bsize) {
			if (error >= 0)
				error = -EIO;
			goto fail;
		}

		from = buf;
		to = (u64 *)((char *)buf + sdp->sd_hash_bsize);

		for (x = sdp->sd_hash_ptrs; x--; from++) {
			*to++ = *from;	/*  No endianess worries  */
			*to++ = *from;
		}

		error = gfs2_dir_write_data(dip,
					     (char *)buf + sdp->sd_hash_bsize,
					     block * sdp->sd_sb.sb_bsize,
					     sdp->sd_sb.sb_bsize);
		if (error != sdp->sd_sb.sb_bsize) {
			if (error >= 0)
				error = -EIO;
			goto fail;
		}
	}

	kfree(buf);

	error = gfs2_meta_inode_buffer(dip, &dibh);
	if (!gfs2_assert_withdraw(sdp, !error)) {
		dip->i_di.di_depth++;
		gfs2_dinode_out(dip, dibh->b_data);
		brelse(dibh);
	}

	return error;

fail:
	kfree(buf);
	return error;
}

/**
 * compare_dents - compare directory entries by hash value
 * @a: first dent
 * @b: second dent
 *
 * When comparing the hash entries of @a to @b:
 *   gt: returns 1
 *   lt: returns -1
 *   eq: returns 0
 */

static int compare_dents(const void *a, const void *b)
{
	const struct gfs2_dirent *dent_a, *dent_b;
	u32 hash_a, hash_b;
	int ret = 0;

	dent_a = *(const struct gfs2_dirent **)a;
	hash_a = be32_to_cpu(dent_a->de_hash);

	dent_b = *(const struct gfs2_dirent **)b;
	hash_b = be32_to_cpu(dent_b->de_hash);

	if (hash_a > hash_b)
		ret = 1;
	else if (hash_a < hash_b)
		ret = -1;
	else {
		unsigned int len_a = be16_to_cpu(dent_a->de_name_len);
		unsigned int len_b = be16_to_cpu(dent_b->de_name_len);

		if (len_a > len_b)
			ret = 1;
		else if (len_a < len_b)
			ret = -1;
		else
			ret = memcmp(dent_a + 1, dent_b + 1, len_a);
	}

	return ret;
}

/**
 * do_filldir_main - read out directory entries
 * @dip: The GFS2 inode
 * @offset: The offset in the file to read from
 * @opaque: opaque data to pass to filldir
 * @filldir: The function to pass entries to
 * @darr: an array of struct gfs2_dirent pointers to read
 * @entries: the number of entries in darr
 * @copied: pointer to int that's non-zero if a entry has been copied out
 *
 * Jump through some hoops to make sure that if there are hash collsions,
 * they are read out at the beginning of a buffer.  We want to minimize
 * the possibility that they will fall into different readdir buffers or
 * that someone will want to seek to that location.
 *
 * Returns: errno, >0 on exception from filldir
 */

static int do_filldir_main(struct gfs2_inode *dip, u64 *offset,
			   void *opaque, filldir_t filldir,
			   const struct gfs2_dirent **darr, u32 entries,
			   int *copied)
{
	const struct gfs2_dirent *dent, *dent_next;
	u64 off, off_next;
	unsigned int x, y;
	int run = 0;
	int error = 0;

	sort(darr, entries, sizeof(struct gfs2_dirent *), compare_dents, NULL);

	dent_next = darr[0];
	off_next = be32_to_cpu(dent_next->de_hash);
	off_next = gfs2_disk_hash2offset(off_next);

	for (x = 0, y = 1; x < entries; x++, y++) {
		dent = dent_next;
		off = off_next;

		if (y < entries) {
			dent_next = darr[y];
			off_next = be32_to_cpu(dent_next->de_hash);
			off_next = gfs2_disk_hash2offset(off_next);

			if (off < *offset)
				continue;
			*offset = off;

			if (off_next == off) {
				if (*copied && !run)
					return 1;
				run = 1;
			} else
				run = 0;
		} else {
			if (off < *offset)
				continue;
			*offset = off;
		}

		error = filldir(opaque, (const char *)(dent + 1),
				be16_to_cpu(dent->de_name_len),
				off, be64_to_cpu(dent->de_inum.no_addr),
				be16_to_cpu(dent->de_type));
		if (error)
			return 1;

		*copied = 1;
	}

	/* Increment the *offset by one, so the next time we come into the
	   do_filldir fxn, we get the next entry instead of the last one in the
	   current leaf */

	(*offset)++;

	return 0;
}

static int gfs2_dir_read_leaf(struct inode *inode, u64 *offset, void *opaque,
			      filldir_t filldir, int *copied, unsigned *depth,
			      u64 leaf_no)
{
	struct gfs2_inode *ip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	struct buffer_head *bh;
	struct gfs2_leaf *lf;
	unsigned entries = 0, entries2 = 0;
	unsigned leaves = 0;
	const struct gfs2_dirent **darr, *dent;
	struct dirent_gather g;
	struct buffer_head **larr;
	int leaf = 0;
	int error, i;
	u64 lfn = leaf_no;

	do {
		error = get_leaf(ip, lfn, &bh);
		if (error)
			goto out;
		lf = (struct gfs2_leaf *)bh->b_data;
		if (leaves == 0)
			*depth = be16_to_cpu(lf->lf_depth);
		entries += be16_to_cpu(lf->lf_entries);
		leaves++;
		lfn = be64_to_cpu(lf->lf_next);
		brelse(bh);
	} while(lfn);

	if (!entries)
		return 0;

	error = -ENOMEM;
	/*
	 * The extra 99 entries are not normally used, but are a buffer
	 * zone in case the number of entries in the leaf is corrupt.
	 * 99 is the maximum number of entries that can fit in a single
	 * leaf block.
	 */
	larr = vmalloc((leaves + entries + 99) * sizeof(void *));
	if (!larr)
		goto out;
	darr = (const struct gfs2_dirent **)(larr + leaves);
	g.pdent = darr;
	g.offset = 0;
	lfn = leaf_no;

	do {
		error = get_leaf(ip, lfn, &bh);
		if (error)
			goto out_kfree;
		lf = (struct gfs2_leaf *)bh->b_data;
		lfn = be64_to_cpu(lf->lf_next);
		if (lf->lf_entries) {
			entries2 += be16_to_cpu(lf->lf_entries);
			dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
						gfs2_dirent_gather, NULL, &g);
			error = PTR_ERR(dent);
			if (IS_ERR(dent))
				goto out_kfree;
			if (entries2 != g.offset) {
				fs_warn(sdp, "Number of entries corrupt in dir "
						"leaf %llu, entries2 (%u) != "
						"g.offset (%u)\n",
					(unsigned long long)bh->b_blocknr,
					entries2, g.offset);
					
				error = -EIO;
				goto out_kfree;
			}
			error = 0;
			larr[leaf++] = bh;
		} else {
			brelse(bh);
		}
	} while(lfn);

	BUG_ON(entries2 != entries);
	error = do_filldir_main(ip, offset, opaque, filldir, darr,
				entries, copied);
out_kfree:
	for(i = 0; i < leaf; i++)
		brelse(larr[i]);
	vfree(larr);
out:
	return error;
}

/**
 * dir_e_read - Reads the entries from a directory into a filldir buffer
 * @dip: dinode pointer
 * @offset: the hash of the last entry read shifted to the right once
 * @opaque: buffer for the filldir function to fill
 * @filldir: points to the filldir function to use
 *
 * Returns: errno
 */

static int dir_e_read(struct inode *inode, u64 *offset, void *opaque,
		      filldir_t filldir)
{
	struct gfs2_inode *dip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	u32 hsize, len = 0;
	u32 ht_offset, lp_offset, ht_offset_cur = -1;
	u32 hash, index;
	__be64 *lp;
	int copied = 0;
	int error = 0;
	unsigned depth = 0;

	hsize = 1 << dip->i_di.di_depth;
	if (hsize * sizeof(u64) != dip->i_di.di_size) {
		gfs2_consist_inode(dip);
		return -EIO;
	}

	hash = gfs2_dir_offset2hash(*offset);
	index = hash >> (32 - dip->i_di.di_depth);

	lp = kmalloc(sdp->sd_hash_bsize, GFP_KERNEL);
	if (!lp)
		return -ENOMEM;

	while (index < hsize) {
		lp_offset = index & (sdp->sd_hash_ptrs - 1);
		ht_offset = index - lp_offset;

		if (ht_offset_cur != ht_offset) {
			error = gfs2_dir_read_data(dip, (char *)lp,
						ht_offset * sizeof(__be64),
						sdp->sd_hash_bsize, 1);
			if (error != sdp->sd_hash_bsize) {
				if (error >= 0)
					error = -EIO;
				goto out;
			}
			ht_offset_cur = ht_offset;
		}

		error = gfs2_dir_read_leaf(inode, offset, opaque, filldir,
					   &copied, &depth,
					   be64_to_cpu(lp[lp_offset]));
		if (error)
			break;

		len = 1 << (dip->i_di.di_depth - depth);
		index = (index & ~(len - 1)) + len;
	}

out:
	kfree(lp);
	if (error > 0)
		error = 0;
	return error;
}

int gfs2_dir_read(struct inode *inode, u64 *offset, void *opaque,
		  filldir_t filldir)
{
	struct gfs2_inode *dip = GFS2_I(inode);
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	struct dirent_gather g;
	const struct gfs2_dirent **darr, *dent;
	struct buffer_head *dibh;
	int copied = 0;
	int error;

	if (!dip->i_di.di_entries)
		return 0;

	if (dip->i_di.di_flags & GFS2_DIF_EXHASH)
		return dir_e_read(inode, offset, opaque, filldir);

	if (!gfs2_is_stuffed(dip)) {
		gfs2_consist_inode(dip);
		return -EIO;
	}

	error = gfs2_meta_inode_buffer(dip, &dibh);
	if (error)
		return error;

	error = -ENOMEM;
	/* 96 is max number of dirents which can be stuffed into an inode */
	darr = kmalloc(96 * sizeof(struct gfs2_dirent *), GFP_KERNEL);
	if (darr) {
		g.pdent = darr;
		g.offset = 0;
		dent = gfs2_dirent_scan(inode, dibh->b_data, dibh->b_size,
					gfs2_dirent_gather, NULL, &g);
		if (IS_ERR(dent)) {
			error = PTR_ERR(dent);
			goto out;
		}
		if (dip->i_di.di_entries != g.offset) {
			fs_warn(sdp, "Number of entries corrupt in dir %llu, "
				"ip->i_di.di_entries (%u) != g.offset (%u)\n",
				(unsigned long long)dip->i_no_addr,
				dip->i_di.di_entries,
				g.offset);
			error = -EIO;
			goto out;
		}
		error = do_filldir_main(dip, offset, opaque, filldir, darr,
					dip->i_di.di_entries, &copied);
out:
		kfree(darr);
	}

	if (error > 0)
		error = 0;

	brelse(dibh);

	return error;
}

/**
 * gfs2_dir_search - Search a directory
 * @dip: The GFS2 inode
 * @filename:
 * @inode:
 *
 * This routine searches a directory for a file or another directory.
 * Assumes a glock is held on dip.
 *
 * Returns: errno
 */

struct inode *gfs2_dir_search(struct inode *dir, const struct qstr *name)
{
	struct buffer_head *bh;
	struct gfs2_dirent *dent;
	struct inode *inode;

	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
	if (dent) {
		if (IS_ERR(dent))
			return ERR_PTR(PTR_ERR(dent));
		inode = gfs2_inode_lookup(dir->i_sb, 
				be16_to_cpu(dent->de_type),
				be64_to_cpu(dent->de_inum.no_addr),
				be64_to_cpu(dent->de_inum.no_formal_ino), 0);
		brelse(bh);
		return inode;
	}
	return ERR_PTR(-ENOENT);
}

int gfs2_dir_check(struct inode *dir, const struct qstr *name,
		   const struct gfs2_inode *ip)
{
	struct buffer_head *bh;
	struct gfs2_dirent *dent;
	int ret = -ENOENT;

	dent = gfs2_dirent_search(dir, name, gfs2_dirent_find, &bh);
	if (dent) {
		if (IS_ERR(dent))