[mirror_ubuntu-hirsute-kernel.git] / fs / xfs / xfs_symlink.c

/*
 * Copyright (c) 2000-2006 Silicon Graphics, Inc.
 * Copyright (c) 2012-2013 Red Hat, Inc.
 * All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_fs.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_dir2.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap_util.h"
#include "xfs_error.h"
#include "xfs_quota.h"
#include "xfs_trans_space.h"
#include "xfs_trace.h"
#include "xfs_symlink.h"
#include "xfs_trans.h"
#include "xfs_log.h"
#include "xfs_dinode.h"

/* ----- Kernel only functions below ----- */
STATIC int
xfs_readlink_bmap(
	struct xfs_inode	*ip,
	char			*link)
{
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_bmbt_irec	mval[XFS_SYMLINK_MAPS];
	struct xfs_buf		*bp;
	xfs_daddr_t		d;
	char			*cur_chunk;
	int			pathlen = ip->i_d.di_size;
	int			nmaps = XFS_SYMLINK_MAPS;
	int			byte_cnt;
	int			n;
	int			error = 0;
	int			fsblocks = 0;
	int			offset;

	fsblocks = xfs_symlink_blocks(mp, pathlen);
	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
	if (error)
		goto out;

	offset = 0;
	for (n = 0; n < nmaps; n++) {
		d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
		byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);

		bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
				  &xfs_symlink_buf_ops);
		if (!bp)
			return XFS_ERROR(ENOMEM);
		error = bp->b_error;
		if (error) {
			xfs_buf_ioerror_alert(bp, __func__);
			xfs_buf_relse(bp);

			/* bad CRC means corrupted metadata */
			if (error == EFSBADCRC)
				error = EFSCORRUPTED;
			goto out;
		}
		byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
		if (pathlen < byte_cnt)
			byte_cnt = pathlen;

		cur_chunk = bp->b_addr;
		if (xfs_sb_version_hascrc(&mp->m_sb)) {
			if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset,
							byte_cnt, bp)) {
				error = EFSCORRUPTED;
				xfs_alert(mp,
"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
					offset, byte_cnt, ip->i_ino);
				xfs_buf_relse(bp);
				goto out;

			}

			cur_chunk += sizeof(struct xfs_dsymlink_hdr);
		}

		memcpy(link + offset, bp->b_addr, byte_cnt);

		pathlen -= byte_cnt;
		offset += byte_cnt;

		xfs_buf_relse(bp);
	}
	ASSERT(pathlen == 0);

	link[ip->i_d.di_size] = '\0';
	error = 0;

 out:
	return error;
}

int
xfs_readlink(
	struct xfs_inode *ip,
	char		*link)
{
	struct xfs_mount *mp = ip->i_mount;
	xfs_fsize_t	pathlen;
	int		error = 0;

	trace_xfs_readlink(ip);

	if (XFS_FORCED_SHUTDOWN(mp))
		return XFS_ERROR(EIO);

	xfs_ilock(ip, XFS_ILOCK_SHARED);

	pathlen = ip->i_d.di_size;
	if (!pathlen)
		goto out;

	if (pathlen < 0 || pathlen > MAXPATHLEN) {
		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
			 __func__, (unsigned long long) ip->i_ino,
			 (long long) pathlen);
		ASSERT(0);
		error = XFS_ERROR(EFSCORRUPTED);
		goto out;
	}


	if (ip->i_df.if_flags & XFS_IFINLINE) {
		memcpy(link, ip->i_df.if_u1.if_data, pathlen);
		link[pathlen] = '\0';
	} else {
		error = xfs_readlink_bmap(ip, link);
	}

 out:
	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	return error;
}

int
xfs_symlink(
	struct xfs_inode	*dp,
	struct xfs_name		*link_name,
	const char		*target_path,
	umode_t			mode,
	struct xfs_inode	**ipp)
{
	struct xfs_mount	*mp = dp->i_mount;
	struct xfs_trans	*tp = NULL;
	struct xfs_inode	*ip = NULL;
	int			error = 0;
	int			pathlen;
	struct xfs_bmap_free	free_list;
	xfs_fsblock_t		first_block;
	bool			unlock_dp_on_error = false;
	uint			cancel_flags;
	int			committed;
	xfs_fileoff_t		first_fsb;
	xfs_filblks_t		fs_blocks;
	int			nmaps;
	struct xfs_bmbt_irec	mval[XFS_SYMLINK_MAPS];
	xfs_daddr_t		d;
	const char		*cur_chunk;
	int			byte_cnt;
	int			n;
	xfs_buf_t		*bp;
	prid_t			prid;
	struct xfs_dquot	*udqp = NULL;
	struct xfs_dquot	*gdqp = NULL;
	struct xfs_dquot	*pdqp = NULL;
	uint			resblks;

	*ipp = NULL;

	trace_xfs_symlink(dp, link_name);

	if (XFS_FORCED_SHUTDOWN(mp))
		return XFS_ERROR(EIO);

	/*
	 * Check component lengths of the target path name.
	 */
	pathlen = strlen(target_path);
	if (pathlen >= MAXPATHLEN)      /* total string too long */
		return XFS_ERROR(ENAMETOOLONG);

	udqp = gdqp = NULL;
	prid = xfs_get_initial_prid(dp);

	/*
	 * Make sure that we have allocated dquot(s) on disk.
	 */
	error = xfs_qm_vop_dqalloc(dp,
			xfs_kuid_to_uid(current_fsuid()),
			xfs_kgid_to_gid(current_fsgid()), prid,
			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
			&udqp, &gdqp, &pdqp);
	if (error)
		goto std_return;

	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
	/*
	 * The symlink will fit into the inode data fork?
	 * There can't be any attributes so we get the whole variable part.
	 */
	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
		fs_blocks = 0;
	else
		fs_blocks = xfs_symlink_blocks(mp, pathlen);
	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
	if (error == ENOSPC && fs_blocks == 0) {
		resblks = 0;
		error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
	}
	if (error) {
		cancel_flags = 0;
		goto error_return;
	}

	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
	unlock_dp_on_error = true;

	/*
	 * Check whether the directory allows new symlinks or not.
	 */
	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
		error = XFS_ERROR(EPERM);
		goto error_return;
	}

	/*
	 * Reserve disk quota : blocks and inode.
	 */
	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
						pdqp, resblks, 1, 0);
	if (error)
		goto error_return;

	/*
	 * Check for ability to enter directory entry, if no space reserved.
	 */
	error = xfs_dir_canenter(tp, dp, link_name, resblks);
	if (error)
		goto error_return;
	/*
	 * Initialize the bmap freelist prior to calling either
	 * bmapi or the directory create code.
	 */
	xfs_bmap_init(&free_list, &first_block);

	/*
	 * Allocate an inode for the symlink.
	 */
	error = xfs_dir_ialloc(&tp, dp, S_IFLNK | (mode & ~S_IFMT), 1, 0,
			       prid, resblks > 0, &ip, NULL);
	if (error) {
		if (error == ENOSPC)
			goto error_return;
		goto error1;
	}

	/*
	 * An error after we've joined dp to the transaction will result in the
	 * transaction cancel unlocking dp so don't do it explicitly in the
	 * error path.
	 */
	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
	unlock_dp_on_error = false;

	/*
	 * Also attach the dquot(s) to it, if applicable.
	 */
	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);

	if (resblks)
		resblks -= XFS_IALLOC_SPACE_RES(mp);
	/*
	 * If the symlink will fit into the inode, write it inline.
	 */
	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
		xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
		memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
		ip->i_d.di_size = pathlen;

		/*
		 * The inode was initially created in extent format.
		 */
		ip->i_df.if_flags &= ~(XFS_IFEXTENTS | XFS_IFBROOT);
		ip->i_df.if_flags |= XFS_IFINLINE;

		ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
		xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);

	} else {
		int	offset;

		first_fsb = 0;
		nmaps = XFS_SYMLINK_MAPS;

		error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
				  XFS_BMAPI_METADATA, &first_block, resblks,
				  mval, &nmaps, &free_list);
		if (error)
			goto error2;

		if (resblks)
			resblks -= fs_blocks;
		ip->i_d.di_size = pathlen;
		xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

		cur_chunk = target_path;
		offset = 0;
		for (n = 0; n < nmaps; n++) {
			char	*buf;

			d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
			byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
			bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
					       BTOBB(byte_cnt), 0);
			if (!bp) {
				error = ENOMEM;
				goto error2;
			}
			bp->b_ops = &xfs_symlink_buf_ops;

			byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
			byte_cnt = min(byte_cnt, pathlen);

			buf = bp->b_addr;
			buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
						   byte_cnt, bp);

			memcpy(buf, cur_chunk, byte_cnt);

			cur_chunk += byte_cnt;
			pathlen -= byte_cnt;
			offset += byte_cnt;

			xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
			xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
							(char *)bp->b_addr);
		}
		ASSERT(pathlen == 0);
	}

	/*
	 * Create the directory entry for the symlink.
	 */
	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
					&first_block, &free_list, resblks);
	if (error)
		goto error2;
	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);

	/*
	 * If this is a synchronous mount, make sure that the
	 * symlink transaction goes to disk before returning to
	 * the user.
	 */
	if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC)) {
		xfs_trans_set_sync(tp);
	}

	error = xfs_bmap_finish(&tp, &free_list, &committed);
	if (error) {
		goto error2;
	}
	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
	xfs_qm_dqrele(udqp);
	xfs_qm_dqrele(gdqp);
	xfs_qm_dqrele(pdqp);

	*ipp = ip;
	return 0;

 error2:
	IRELE(ip);
 error1:
	xfs_bmap_cancel(&free_list);
	cancel_flags |= XFS_TRANS_ABORT;
 error_return:
	xfs_trans_cancel(tp, cancel_flags);
	xfs_qm_dqrele(udqp);
	xfs_qm_dqrele(gdqp);
	xfs_qm_dqrele(pdqp);

	if (unlock_dp_on_error)
		xfs_iunlock(dp, XFS_ILOCK_EXCL);
 std_return:
	return error;
}

/*
 * Free a symlink that has blocks associated with it.
 */
STATIC int
xfs_inactive_symlink_rmt(
	struct xfs_inode *ip)
{
	xfs_buf_t	*bp;
	int		committed;
	int		done;
	int		error;
	xfs_fsblock_t	first_block;
	xfs_bmap_free_t	free_list;
	int		i;
	xfs_mount_t	*mp;
	xfs_bmbt_irec_t	mval[XFS_SYMLINK_MAPS];
	int		nmaps;
	int		size;
	xfs_trans_t	*tp;

	mp = ip->i_mount;
	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
	/*
	 * We're freeing a symlink that has some
	 * blocks allocated to it.  Free the
	 * blocks here.  We know that we've got
	 * either 1 or 2 extents and that we can
	 * free them all in one bunmapi call.
	 */
	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);

	tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
	if (error) {
		xfs_trans_cancel(tp, 0);
		return error;
	}

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, 0);

	/*
	 * Lock the inode, fix the size, and join it to the transaction.
	 * Hold it so in the normal path, we still have it locked for
	 * the second transaction.  In the error paths we need it
	 * held so the cancel won't rele it, see below.
	 */
	size = (int)ip->i_d.di_size;
	ip->i_d.di_size = 0;
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	/*
	 * Find the block(s) so we can inval and unmap them.
	 */
	done = 0;
	xfs_bmap_init(&free_list, &first_block);
	nmaps = ARRAY_SIZE(mval);
	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
				mval, &nmaps, 0);
	if (error)
		goto error_trans_cancel;
	/*
	 * Invalidate the block(s). No validation is done.
	 */
	for (i = 0; i < nmaps; i++) {
		bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
			XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
			XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
		if (!bp) {
			error = ENOMEM;
			goto error_bmap_cancel;
		}
		xfs_trans_binval(tp, bp);
	}
	/*
	 * Unmap the dead block(s) to the free_list.
	 */
	error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
			    &first_block, &free_list, &done);
	if (error)
		goto error_bmap_cancel;
	ASSERT(done);
	/*
	 * Commit the first transaction.  This logs the EFI and the inode.
	 */
	error = xfs_bmap_finish(&tp, &free_list, &committed);
	if (error)
		goto error_bmap_cancel;
	/*
	 * The transaction must have been committed, since there were
	 * actually extents freed by xfs_bunmapi.  See xfs_bmap_finish.
	 * The new tp has the extent freeing and EFDs.
	 */
	ASSERT(committed);
	/*
	 * The first xact was committed, so add the inode to the new one.
	 * Mark it dirty so it will be logged and moved forward in the log as
	 * part of every commit.
	 */
	xfs_trans_ijoin(tp, ip, 0);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	/*
	 * Commit the transaction containing extent freeing and EFDs.
	 */
	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
	if (error) {
		ASSERT(XFS_FORCED_SHUTDOWN(mp));
		goto error_unlock;
	}

	/*
	 * Remove the memory for extent descriptions (just bookkeeping).
	 */
	if (ip->i_df.if_bytes)
		xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
	ASSERT(ip->i_df.if_bytes == 0);

	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	return 0;

error_bmap_cancel:
	xfs_bmap_cancel(&free_list);
error_trans_cancel:
	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES | XFS_TRANS_ABORT);
error_unlock:
	xfs_iunlock(ip, XFS_ILOCK_EXCL);
	return error;
}

/*
 * xfs_inactive_symlink - free a symlink
 */
int
xfs_inactive_symlink(
	struct xfs_inode	*ip)
{
	struct xfs_mount	*mp = ip->i_mount;
	int			pathlen;

	trace_xfs_inactive_symlink(ip);

	if (XFS_FORCED_SHUTDOWN(mp))
		return XFS_ERROR(EIO);

	xfs_ilock(ip, XFS_ILOCK_EXCL);

	/*
	 * Zero length symlinks _can_ exist.
	 */
	pathlen = (int)ip->i_d.di_size;
	if (!pathlen) {
		xfs_iunlock(ip, XFS_ILOCK_EXCL);
		return 0;
	}

	if (pathlen < 0 || pathlen > MAXPATHLEN) {
		xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
			 __func__, (unsigned long long)ip->i_ino, pathlen);
		xfs_iunlock(ip, XFS_ILOCK_EXCL);
		ASSERT(0);
		return XFS_ERROR(EFSCORRUPTED);
	}

	if (ip->i_df.if_flags & XFS_IFINLINE) {
		if (ip->i_df.if_bytes > 0) 
			xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
					  XFS_DATA_FORK);
		xfs_iunlock(ip, XFS_ILOCK_EXCL);
		ASSERT(ip->i_df.if_bytes == 0);
		return 0;
	}

	xfs_iunlock(ip, XFS_ILOCK_EXCL);

	/* remove the remote symlink */
	return xfs_inactive_symlink_rmt(ip);
}
Commit	Line	Data
19de7351 DC	1	/*
	2	* Copyright (c) 2000-2006 Silicon Graphics, Inc.
	3	* Copyright (c) 2012-2013 Red Hat, Inc.
	4	* All rights reserved.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it would be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program; if not, write the Free Software Foundation,
	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	18	*/
	19	#include "xfs.h"
239880ef	20	#include "xfs_shared.h"
19de7351	21	#include "xfs_fs.h"
6ca1c906	22	#include "xfs_format.h"
239880ef DC	23	#include "xfs_log_format.h"
239880ef DC	24	#include "xfs_trans_resv.h"
19de7351	25	#include "xfs_bit.h"
19de7351 DC	26	#include "xfs_sb.h"
19de7351 DC	27	#include "xfs_ag.h"
19de7351	28	#include "xfs_mount.h"
57062787	29	#include "xfs_da_format.h"
2b9ab5ab	30	#include "xfs_dir2.h"
19de7351	31	#include "xfs_inode.h"
19de7351 DC	32	#include "xfs_ialloc.h"
	33	#include "xfs_alloc.h"
	34	#include "xfs_bmap.h"
a4fbe6ab	35	#include "xfs_bmap_btree.h"
68988114	36	#include "xfs_bmap_util.h"
19de7351 DC	37	#include "xfs_error.h"
19de7351 DC	38	#include "xfs_quota.h"
19de7351	39	#include "xfs_trans_space.h"
19de7351 DC	40	#include "xfs_trace.h"
19de7351 DC	41	#include "xfs_symlink.h"
239880ef	42	#include "xfs_trans.h"
239880ef	43	#include "xfs_log.h"
a4fbe6ab	44	#include "xfs_dinode.h"
19de7351 DC	45
19de7351 DC	46	/* ----- Kernel only functions below ----- */
19de7351 DC	47	STATIC int
19de7351 DC	48	xfs_readlink_bmap(
f948dd76 DC	49	struct xfs_inode *ip,
f948dd76 DC	50	char *link)
19de7351	51	{
f948dd76 DC	52	struct xfs_mount *mp = ip->i_mount;
	53	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
	54	struct xfs_buf *bp;
	55	xfs_daddr_t d;
	56	char *cur_chunk;
	57	int pathlen = ip->i_d.di_size;
	58	int nmaps = XFS_SYMLINK_MAPS;
	59	int byte_cnt;
	60	int n;
	61	int error = 0;
	62	int fsblocks = 0;
	63	int offset;
19de7351	64
f948dd76 DC	65	fsblocks = xfs_symlink_blocks(mp, pathlen);
f948dd76 DC	66	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
19de7351 DC	67	if (error)
	68	goto out;
	69
f948dd76	70	offset = 0;
19de7351 DC	71	for (n = 0; n < nmaps; n++) {
	72	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	73	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	74
f948dd76 DC	75	bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
f948dd76 DC	76	&xfs_symlink_buf_ops);
19de7351 DC	77	if (!bp)
	78	return XFS_ERROR(ENOMEM);
	79	error = bp->b_error;
	80	if (error) {
	81	xfs_buf_ioerror_alert(bp, __func__);
	82	xfs_buf_relse(bp);
ac75a1f7 DC	83
	84	/* bad CRC means corrupted metadata */
	85	if (error == EFSBADCRC)
	86	error = EFSCORRUPTED;
19de7351 DC	87	goto out;
19de7351 DC	88	}
f948dd76	89	byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
19de7351 DC	90	if (pathlen < byte_cnt)
19de7351 DC	91	byte_cnt = pathlen;
f948dd76 DC	92
	93	cur_chunk = bp->b_addr;
	94	if (xfs_sb_version_hascrc(&mp->m_sb)) {
	95	if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset,
	96	byte_cnt, bp)) {
	97	error = EFSCORRUPTED;
	98	xfs_alert(mp,
	99	"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
	100	offset, byte_cnt, ip->i_ino);
	101	xfs_buf_relse(bp);
	102	goto out;
	103
	104	}
	105
	106	cur_chunk += sizeof(struct xfs_dsymlink_hdr);
	107	}
	108
	109	memcpy(link + offset, bp->b_addr, byte_cnt);
	110
19de7351	111	pathlen -= byte_cnt;
f948dd76	112	offset += byte_cnt;
19de7351	113
19de7351 DC	114	xfs_buf_relse(bp);
19de7351 DC	115	}
f948dd76	116	ASSERT(pathlen == 0);
19de7351 DC	117
	118	link[ip->i_d.di_size] = '\0';
	119	error = 0;
	120
	121	out:
	122	return error;
	123	}
	124
	125	int
	126	xfs_readlink(
f948dd76	127	struct xfs_inode *ip,
19de7351 DC	128	char *link)
19de7351 DC	129	{
f948dd76	130	struct xfs_mount *mp = ip->i_mount;
19de7351 DC	131	xfs_fsize_t pathlen;
	132	int error = 0;
	133
	134	trace_xfs_readlink(ip);
	135
	136	if (XFS_FORCED_SHUTDOWN(mp))
	137	return XFS_ERROR(EIO);
	138
	139	xfs_ilock(ip, XFS_ILOCK_SHARED);
	140
	141	pathlen = ip->i_d.di_size;
	142	if (!pathlen)
	143	goto out;
	144
	145	if (pathlen < 0 \|\| pathlen > MAXPATHLEN) {
	146	xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
	147	__func__, (unsigned long long) ip->i_ino,
	148	(long long) pathlen);
	149	ASSERT(0);
	150	error = XFS_ERROR(EFSCORRUPTED);
	151	goto out;
	152	}
	153
	154
	155	if (ip->i_df.if_flags & XFS_IFINLINE) {
	156	memcpy(link, ip->i_df.if_u1.if_data, pathlen);
	157	link[pathlen] = '\0';
	158	} else {
	159	error = xfs_readlink_bmap(ip, link);
	160	}
	161
	162	out:
	163	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	164	return error;
	165	}
	166
	167	int
	168	xfs_symlink(
f948dd76	169	struct xfs_inode *dp,
19de7351 DC	170	struct xfs_name *link_name,
	171	const char *target_path,
	172	umode_t mode,
f948dd76	173	struct xfs_inode **ipp)
19de7351	174	{
f948dd76 DC	175	struct xfs_mount *mp = dp->i_mount;
	176	struct xfs_trans *tp = NULL;
	177	struct xfs_inode *ip = NULL;
	178	int error = 0;
19de7351	179	int pathlen;
f948dd76	180	struct xfs_bmap_free free_list;
19de7351	181	xfs_fsblock_t first_block;
f948dd76	182	bool unlock_dp_on_error = false;
19de7351 DC	183	uint cancel_flags;
	184	int committed;
	185	xfs_fileoff_t first_fsb;
	186	xfs_filblks_t fs_blocks;
	187	int nmaps;
f948dd76	188	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
19de7351 DC	189	xfs_daddr_t d;
	190	const char *cur_chunk;
	191	int byte_cnt;
	192	int n;
	193	xfs_buf_t *bp;
	194	prid_t prid;
113a5683 CS	195	struct xfs_dquot *udqp = NULL;
113a5683 CS	196	struct xfs_dquot *gdqp = NULL;
92f8ff73	197	struct xfs_dquot *pdqp = NULL;
19de7351 DC	198	uint resblks;
	199
	200	*ipp = NULL;
19de7351 DC	201
	202	trace_xfs_symlink(dp, link_name);
	203
	204	if (XFS_FORCED_SHUTDOWN(mp))
	205	return XFS_ERROR(EIO);
	206
	207	/*
	208	* Check component lengths of the target path name.
	209	*/
	210	pathlen = strlen(target_path);
	211	if (pathlen >= MAXPATHLEN) /* total string too long */
	212	return XFS_ERROR(ENAMETOOLONG);
	213
	214	udqp = gdqp = NULL;
163467d3	215	prid = xfs_get_initial_prid(dp);
19de7351 DC	216
	217	/*
	218	* Make sure that we have allocated dquot(s) on disk.
	219	*/
7aab1b28 DE	220	error = xfs_qm_vop_dqalloc(dp,
	221	xfs_kuid_to_uid(current_fsuid()),
	222	xfs_kgid_to_gid(current_fsgid()), prid,
	223	XFS_QMOPT_QUOTALL \| XFS_QMOPT_INHERIT,
	224	&udqp, &gdqp, &pdqp);
19de7351 DC	225	if (error)
	226	goto std_return;
	227
	228	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
	229	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
	230	/*
	231	* The symlink will fit into the inode data fork?
	232	* There can't be any attributes so we get the whole variable part.
	233	*/
	234	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
	235	fs_blocks = 0;
	236	else
321a9583	237	fs_blocks = xfs_symlink_blocks(mp, pathlen);
19de7351	238	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
3d3c8b52	239	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
19de7351 DC	240	if (error == ENOSPC && fs_blocks == 0) {
19de7351 DC	241	resblks = 0;
3d3c8b52	242	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
19de7351 DC	243	}
	244	if (error) {
	245	cancel_flags = 0;
	246	goto error_return;
	247	}
	248
	249	xfs_ilock(dp, XFS_ILOCK_EXCL \| XFS_ILOCK_PARENT);
	250	unlock_dp_on_error = true;
	251
	252	/*
	253	* Check whether the directory allows new symlinks or not.
	254	*/
	255	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
	256	error = XFS_ERROR(EPERM);
	257	goto error_return;
	258	}
	259
	260	/*
	261	* Reserve disk quota : blocks and inode.
	262	*/
92f8ff73 CS	263	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
92f8ff73 CS	264	pdqp, resblks, 1, 0);
19de7351 DC	265	if (error)
	266	goto error_return;
	267
	268	/*
	269	* Check for ability to enter directory entry, if no space reserved.
	270	*/
	271	error = xfs_dir_canenter(tp, dp, link_name, resblks);
	272	if (error)
	273	goto error_return;
	274	/*
	275	* Initialize the bmap freelist prior to calling either
	276	* bmapi or the directory create code.
	277	*/
	278	xfs_bmap_init(&free_list, &first_block);
	279
	280	/*
	281	* Allocate an inode for the symlink.
	282	*/
	283	error = xfs_dir_ialloc(&tp, dp, S_IFLNK \| (mode & ~S_IFMT), 1, 0,
	284	prid, resblks > 0, &ip, NULL);
	285	if (error) {
	286	if (error == ENOSPC)
	287	goto error_return;
	288	goto error1;
	289	}
	290
	291	/*
	292	* An error after we've joined dp to the transaction will result in the
	293	* transaction cancel unlocking dp so don't do it explicitly in the
	294	* error path.
	295	*/
	296	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
	297	unlock_dp_on_error = false;
	298
	299	/*
	300	* Also attach the dquot(s) to it, if applicable.
	301	*/
92f8ff73	302	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
19de7351 DC	303
	304	if (resblks)
	305	resblks -= XFS_IALLOC_SPACE_RES(mp);
	306	/*
	307	* If the symlink will fit into the inode, write it inline.
	308	*/
	309	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
	310	xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
	311	memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
	312	ip->i_d.di_size = pathlen;
	313
	314	/*
	315	* The inode was initially created in extent format.
	316	*/
	317	ip->i_df.if_flags &= ~(XFS_IFEXTENTS \| XFS_IFBROOT);
	318	ip->i_df.if_flags \|= XFS_IFINLINE;
	319
	320	ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
	321	xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA \| XFS_ILOG_CORE);
	322
	323	} else {
f948dd76 DC	324	int offset;
f948dd76 DC	325
19de7351 DC	326	first_fsb = 0;
	327	nmaps = XFS_SYMLINK_MAPS;
	328
	329	error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
	330	XFS_BMAPI_METADATA, &first_block, resblks,
	331	mval, &nmaps, &free_list);
	332	if (error)
	333	goto error2;
	334
	335	if (resblks)
	336	resblks -= fs_blocks;
	337	ip->i_d.di_size = pathlen;
	338	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	339
	340	cur_chunk = target_path;
f948dd76	341	offset = 0;
19de7351	342	for (n = 0; n < nmaps; n++) {
321a9583	343	char *buf;
f948dd76	344
19de7351 DC	345	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	346	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	347	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
	348	BTOBB(byte_cnt), 0);
	349	if (!bp) {
	350	error = ENOMEM;
	351	goto error2;
	352	}
f948dd76 DC	353	bp->b_ops = &xfs_symlink_buf_ops;
	354
	355	byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
321a9583	356	byte_cnt = min(byte_cnt, pathlen);
19de7351	357
f948dd76 DC	358	buf = bp->b_addr;
	359	buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
	360	byte_cnt, bp);
	361
	362	memcpy(buf, cur_chunk, byte_cnt);
	363
19de7351	364	cur_chunk += byte_cnt;
f948dd76 DC	365	pathlen -= byte_cnt;
f948dd76 DC	366	offset += byte_cnt;
19de7351	367
daf7b799	368	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
f948dd76 DC	369	xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
f948dd76 DC	370	(char *)bp->b_addr);
19de7351	371	}
321a9583	372	ASSERT(pathlen == 0);
19de7351 DC	373	}
	374
	375	/*
	376	* Create the directory entry for the symlink.
	377	*/
	378	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
	379	&first_block, &free_list, resblks);
	380	if (error)
	381	goto error2;
	382	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD \| XFS_ICHGTIME_CHG);
	383	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
	384
	385	/*
	386	* If this is a synchronous mount, make sure that the
	387	* symlink transaction goes to disk before returning to
	388	* the user.
	389	*/
	390	if (mp->m_flags & (XFS_MOUNT_WSYNC\|XFS_MOUNT_DIRSYNC)) {
	391	xfs_trans_set_sync(tp);
	392	}
	393
	394	error = xfs_bmap_finish(&tp, &free_list, &committed);
	395	if (error) {
	396	goto error2;
	397	}
	398	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
	399	xfs_qm_dqrele(udqp);
	400	xfs_qm_dqrele(gdqp);
92f8ff73	401	xfs_qm_dqrele(pdqp);
19de7351 DC	402
	403	*ipp = ip;
	404	return 0;
	405
	406	error2:
	407	IRELE(ip);
	408	error1:
	409	xfs_bmap_cancel(&free_list);
	410	cancel_flags \|= XFS_TRANS_ABORT;
	411	error_return:
	412	xfs_trans_cancel(tp, cancel_flags);
	413	xfs_qm_dqrele(udqp);
	414	xfs_qm_dqrele(gdqp);
92f8ff73	415	xfs_qm_dqrele(pdqp);
19de7351 DC	416
	417	if (unlock_dp_on_error)
	418	xfs_iunlock(dp, XFS_ILOCK_EXCL);
	419	std_return:
	420	return error;
	421	}
	422
	423	/*
	424	* Free a symlink that has blocks associated with it.
	425	*/
725eb1eb	426	STATIC int
19de7351	427	xfs_inactive_symlink_rmt(
36b21dde	428	struct xfs_inode *ip)
19de7351 DC	429	{
	430	xfs_buf_t *bp;
	431	int committed;
	432	int done;
	433	int error;
	434	xfs_fsblock_t first_block;
	435	xfs_bmap_free_t free_list;
	436	int i;
	437	xfs_mount_t *mp;
	438	xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
	439	int nmaps;
19de7351 DC	440	int size;
	441	xfs_trans_t *tp;
	442
19de7351	443	mp = ip->i_mount;
725eb1eb	444	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
19de7351 DC	445	/*
	446	* We're freeing a symlink that has some
	447	* blocks allocated to it. Free the
	448	* blocks here. We know that we've got
	449	* either 1 or 2 extents and that we can
	450	* free them all in one bunmapi call.
	451	*/
	452	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
	453
36b21dde BF	454	tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
	455	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
	456	if (error) {
	457	xfs_trans_cancel(tp, 0);
	458	return error;
	459	}
	460
	461	xfs_ilock(ip, XFS_ILOCK_EXCL);
	462	xfs_trans_ijoin(tp, ip, 0);
	463
19de7351 DC	464	/*
	465	* Lock the inode, fix the size, and join it to the transaction.
	466	* Hold it so in the normal path, we still have it locked for
	467	* the second transaction. In the error paths we need it
	468	* held so the cancel won't rele it, see below.
	469	*/
	470	size = (int)ip->i_d.di_size;
	471	ip->i_d.di_size = 0;
	472	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	473	/*
	474	* Find the block(s) so we can inval and unmap them.
	475	*/
	476	done = 0;
	477	xfs_bmap_init(&free_list, &first_block);
	478	nmaps = ARRAY_SIZE(mval);
f948dd76	479	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
19de7351 DC	480	mval, &nmaps, 0);
19de7351 DC	481	if (error)
36b21dde	482	goto error_trans_cancel;
19de7351	483	/*
f948dd76	484	* Invalidate the block(s). No validation is done.
19de7351 DC	485	*/
	486	for (i = 0; i < nmaps; i++) {
	487	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
	488	XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
	489	XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
	490	if (!bp) {
	491	error = ENOMEM;
36b21dde	492	goto error_bmap_cancel;
19de7351 DC	493	}
	494	xfs_trans_binval(tp, bp);
	495	}
	496	/*
	497	* Unmap the dead block(s) to the free_list.
	498	*/
36b21dde BF	499	error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
	500	&first_block, &free_list, &done);
	501	if (error)
	502	goto error_bmap_cancel;
19de7351 DC	503	ASSERT(done);
	504	/*
	505	* Commit the first transaction. This logs the EFI and the inode.
	506	*/
36b21dde BF	507	error = xfs_bmap_finish(&tp, &free_list, &committed);
	508	if (error)
	509	goto error_bmap_cancel;
19de7351 DC	510	/*
	511	* The transaction must have been committed, since there were
	512	* actually extents freed by xfs_bunmapi. See xfs_bmap_finish.
	513	* The new tp has the extent freeing and EFDs.
	514	*/
	515	ASSERT(committed);
	516	/*
	517	* The first xact was committed, so add the inode to the new one.
	518	* Mark it dirty so it will be logged and moved forward in the log as
	519	* part of every commit.
	520	*/
	521	xfs_trans_ijoin(tp, ip, 0);
	522	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
19de7351 DC	523	/*
19de7351 DC	524	* Commit the transaction containing extent freeing and EFDs.
19de7351	525	*/
36b21dde	526	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
19de7351 DC	527	if (error) {
19de7351 DC	528	ASSERT(XFS_FORCED_SHUTDOWN(mp));
36b21dde	529	goto error_unlock;
19de7351	530	}
19de7351 DC	531
	532	/*
	533	* Remove the memory for extent descriptions (just bookkeeping).
	534	*/
	535	if (ip->i_df.if_bytes)
	536	xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
	537	ASSERT(ip->i_df.if_bytes == 0);
19de7351	538
36b21dde	539	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	540	return 0;
19de7351 DC	541
36b21dde	542	error_bmap_cancel:
19de7351	543	xfs_bmap_cancel(&free_list);
36b21dde BF	544	error_trans_cancel:
	545	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES \| XFS_TRANS_ABORT);
	546	error_unlock:
	547	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	548	return error;
19de7351 DC	549	}
725eb1eb MT	550
	551	/*
	552	* xfs_inactive_symlink - free a symlink
	553	*/
	554	int
	555	xfs_inactive_symlink(
36b21dde	556	struct xfs_inode *ip)
725eb1eb MT	557	{
	558	struct xfs_mount *mp = ip->i_mount;
	559	int pathlen;
	560
	561	trace_xfs_inactive_symlink(ip);
	562
725eb1eb MT	563	if (XFS_FORCED_SHUTDOWN(mp))
	564	return XFS_ERROR(EIO);
	565
36b21dde BF	566	xfs_ilock(ip, XFS_ILOCK_EXCL);
36b21dde BF	567
725eb1eb MT	568	/*
	569	* Zero length symlinks _can_ exist.
	570	*/
	571	pathlen = (int)ip->i_d.di_size;
36b21dde BF	572	if (!pathlen) {
36b21dde BF	573	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb	574	return 0;
36b21dde	575	}
725eb1eb MT	576
	577	if (pathlen < 0 \|\| pathlen > MAXPATHLEN) {
	578	xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
	579	__func__, (unsigned long long)ip->i_ino, pathlen);
36b21dde	580	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb MT	581	ASSERT(0);
	582	return XFS_ERROR(EFSCORRUPTED);
	583	}
	584
	585	if (ip->i_df.if_flags & XFS_IFINLINE) {
36b21dde	586	if (ip->i_df.if_bytes > 0)
725eb1eb MT	587	xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
725eb1eb MT	588	XFS_DATA_FORK);
36b21dde	589	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb MT	590	ASSERT(ip->i_df.if_bytes == 0);
	591	return 0;
	592	}
	593
36b21dde BF	594	xfs_iunlock(ip, XFS_ILOCK_EXCL);
36b21dde BF	595
725eb1eb	596	/* remove the remote symlink */
36b21dde	597	return xfs_inactive_symlink_rmt(ip);
725eb1eb	598	}