[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_bmap_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_alloc.h"
#include "xfs_bmap.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_buf_item.h"
#include "xfs_log.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);
			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;
	if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
		prid = xfs_get_projid(dp);
	else
		prid = XFS_PROJID_DEFAULT;

	/*
	 * 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 DC	31	#include "xfs_bmap_btree.h"
	32	#include "xfs_ialloc_btree.h"
	33	#include "xfs_dinode.h"
	34	#include "xfs_inode.h"
19de7351 DC	35	#include "xfs_ialloc.h"
	36	#include "xfs_alloc.h"
	37	#include "xfs_bmap.h"
68988114	38	#include "xfs_bmap_util.h"
19de7351 DC	39	#include "xfs_error.h"
19de7351 DC	40	#include "xfs_quota.h"
19de7351	41	#include "xfs_trans_space.h"
19de7351 DC	42	#include "xfs_trace.h"
19de7351 DC	43	#include "xfs_symlink.h"
239880ef	44	#include "xfs_trans.h"
daf7b799	45	#include "xfs_buf_item.h"
239880ef	46	#include "xfs_log.h"
19de7351 DC	47
19de7351 DC	48	/* ----- Kernel only functions below ----- */
19de7351 DC	49	STATIC int
19de7351 DC	50	xfs_readlink_bmap(
f948dd76 DC	51	struct xfs_inode *ip,
f948dd76 DC	52	char *link)
19de7351	53	{
f948dd76 DC	54	struct xfs_mount *mp = ip->i_mount;
	55	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
	56	struct xfs_buf *bp;
	57	xfs_daddr_t d;
	58	char *cur_chunk;
	59	int pathlen = ip->i_d.di_size;
	60	int nmaps = XFS_SYMLINK_MAPS;
	61	int byte_cnt;
	62	int n;
	63	int error = 0;
	64	int fsblocks = 0;
	65	int offset;
19de7351	66
f948dd76 DC	67	fsblocks = xfs_symlink_blocks(mp, pathlen);
f948dd76 DC	68	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
19de7351 DC	69	if (error)
	70	goto out;
	71
f948dd76	72	offset = 0;
19de7351 DC	73	for (n = 0; n < nmaps; n++) {
	74	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	75	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	76
f948dd76 DC	77	bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
f948dd76 DC	78	&xfs_symlink_buf_ops);
19de7351 DC	79	if (!bp)
	80	return XFS_ERROR(ENOMEM);
	81	error = bp->b_error;
	82	if (error) {
	83	xfs_buf_ioerror_alert(bp, __func__);
	84	xfs_buf_relse(bp);
	85	goto out;
	86	}
f948dd76	87	byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
19de7351 DC	88	if (pathlen < byte_cnt)
19de7351 DC	89	byte_cnt = pathlen;
f948dd76 DC	90
	91	cur_chunk = bp->b_addr;
	92	if (xfs_sb_version_hascrc(&mp->m_sb)) {
	93	if (!xfs_symlink_hdr_ok(mp, ip->i_ino, offset,
	94	byte_cnt, bp)) {
	95	error = EFSCORRUPTED;
	96	xfs_alert(mp,
	97	"symlink header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
	98	offset, byte_cnt, ip->i_ino);
	99	xfs_buf_relse(bp);
	100	goto out;
	101
	102	}
	103
	104	cur_chunk += sizeof(struct xfs_dsymlink_hdr);
	105	}
	106
	107	memcpy(link + offset, bp->b_addr, byte_cnt);
	108
19de7351	109	pathlen -= byte_cnt;
f948dd76	110	offset += byte_cnt;
19de7351	111
19de7351 DC	112	xfs_buf_relse(bp);
19de7351 DC	113	}
f948dd76	114	ASSERT(pathlen == 0);
19de7351 DC	115
	116	link[ip->i_d.di_size] = '\0';
	117	error = 0;
	118
	119	out:
	120	return error;
	121	}
	122
	123	int
	124	xfs_readlink(
f948dd76	125	struct xfs_inode *ip,
19de7351 DC	126	char *link)
19de7351 DC	127	{
f948dd76	128	struct xfs_mount *mp = ip->i_mount;
19de7351 DC	129	xfs_fsize_t pathlen;
	130	int error = 0;
	131
	132	trace_xfs_readlink(ip);
	133
	134	if (XFS_FORCED_SHUTDOWN(mp))
	135	return XFS_ERROR(EIO);
	136
	137	xfs_ilock(ip, XFS_ILOCK_SHARED);
	138
	139	pathlen = ip->i_d.di_size;
	140	if (!pathlen)
	141	goto out;
	142
	143	if (pathlen < 0 \|\| pathlen > MAXPATHLEN) {
	144	xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
	145	__func__, (unsigned long long) ip->i_ino,
	146	(long long) pathlen);
	147	ASSERT(0);
	148	error = XFS_ERROR(EFSCORRUPTED);
	149	goto out;
	150	}
	151
	152
	153	if (ip->i_df.if_flags & XFS_IFINLINE) {
	154	memcpy(link, ip->i_df.if_u1.if_data, pathlen);
	155	link[pathlen] = '\0';
	156	} else {
	157	error = xfs_readlink_bmap(ip, link);
	158	}
	159
	160	out:
	161	xfs_iunlock(ip, XFS_ILOCK_SHARED);
	162	return error;
	163	}
	164
	165	int
	166	xfs_symlink(
f948dd76	167	struct xfs_inode *dp,
19de7351 DC	168	struct xfs_name *link_name,
	169	const char *target_path,
	170	umode_t mode,
f948dd76	171	struct xfs_inode **ipp)
19de7351	172	{
f948dd76 DC	173	struct xfs_mount *mp = dp->i_mount;
	174	struct xfs_trans *tp = NULL;
	175	struct xfs_inode *ip = NULL;
	176	int error = 0;
19de7351	177	int pathlen;
f948dd76	178	struct xfs_bmap_free free_list;
19de7351	179	xfs_fsblock_t first_block;
f948dd76	180	bool unlock_dp_on_error = false;
19de7351 DC	181	uint cancel_flags;
	182	int committed;
	183	xfs_fileoff_t first_fsb;
	184	xfs_filblks_t fs_blocks;
	185	int nmaps;
f948dd76	186	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
19de7351 DC	187	xfs_daddr_t d;
	188	const char *cur_chunk;
	189	int byte_cnt;
	190	int n;
	191	xfs_buf_t *bp;
	192	prid_t prid;
113a5683 CS	193	struct xfs_dquot *udqp = NULL;
113a5683 CS	194	struct xfs_dquot *gdqp = NULL;
92f8ff73	195	struct xfs_dquot *pdqp = NULL;
19de7351 DC	196	uint resblks;
	197
	198	*ipp = NULL;
19de7351 DC	199
	200	trace_xfs_symlink(dp, link_name);
	201
	202	if (XFS_FORCED_SHUTDOWN(mp))
	203	return XFS_ERROR(EIO);
	204
	205	/*
	206	* Check component lengths of the target path name.
	207	*/
	208	pathlen = strlen(target_path);
	209	if (pathlen >= MAXPATHLEN) /* total string too long */
	210	return XFS_ERROR(ENAMETOOLONG);
	211
	212	udqp = gdqp = NULL;
	213	if (dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT)
	214	prid = xfs_get_projid(dp);
	215	else
	216	prid = XFS_PROJID_DEFAULT;
	217
	218	/*
	219	* Make sure that we have allocated dquot(s) on disk.
	220	*/
7aab1b28 DE	221	error = xfs_qm_vop_dqalloc(dp,
	222	xfs_kuid_to_uid(current_fsuid()),
	223	xfs_kgid_to_gid(current_fsgid()), prid,
	224	XFS_QMOPT_QUOTALL \| XFS_QMOPT_INHERIT,
	225	&udqp, &gdqp, &pdqp);
19de7351 DC	226	if (error)
	227	goto std_return;
	228
	229	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
	230	cancel_flags = XFS_TRANS_RELEASE_LOG_RES;
	231	/*
	232	* The symlink will fit into the inode data fork?
	233	* There can't be any attributes so we get the whole variable part.
	234	*/
	235	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
	236	fs_blocks = 0;
	237	else
321a9583	238	fs_blocks = xfs_symlink_blocks(mp, pathlen);
19de7351	239	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
3d3c8b52	240	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
19de7351 DC	241	if (error == ENOSPC && fs_blocks == 0) {
19de7351 DC	242	resblks = 0;
3d3c8b52	243	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
19de7351 DC	244	}
	245	if (error) {
	246	cancel_flags = 0;
	247	goto error_return;
	248	}
	249
	250	xfs_ilock(dp, XFS_ILOCK_EXCL \| XFS_ILOCK_PARENT);
	251	unlock_dp_on_error = true;
	252
	253	/*
	254	* Check whether the directory allows new symlinks or not.
	255	*/
	256	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
	257	error = XFS_ERROR(EPERM);
	258	goto error_return;
	259	}
	260
	261	/*
	262	* Reserve disk quota : blocks and inode.
	263	*/
92f8ff73 CS	264	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
92f8ff73 CS	265	pdqp, resblks, 1, 0);
19de7351 DC	266	if (error)
	267	goto error_return;
	268
	269	/*
	270	* Check for ability to enter directory entry, if no space reserved.
	271	*/
	272	error = xfs_dir_canenter(tp, dp, link_name, resblks);
	273	if (error)
	274	goto error_return;
	275	/*
	276	* Initialize the bmap freelist prior to calling either
	277	* bmapi or the directory create code.
	278	*/
	279	xfs_bmap_init(&free_list, &first_block);
	280
	281	/*
	282	* Allocate an inode for the symlink.
	283	*/
	284	error = xfs_dir_ialloc(&tp, dp, S_IFLNK \| (mode & ~S_IFMT), 1, 0,
	285	prid, resblks > 0, &ip, NULL);
	286	if (error) {
	287	if (error == ENOSPC)
	288	goto error_return;
	289	goto error1;
	290	}
	291
	292	/*
	293	* An error after we've joined dp to the transaction will result in the
	294	* transaction cancel unlocking dp so don't do it explicitly in the
	295	* error path.
	296	*/
	297	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
	298	unlock_dp_on_error = false;
	299
	300	/*
	301	* Also attach the dquot(s) to it, if applicable.
	302	*/
92f8ff73	303	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
19de7351 DC	304
	305	if (resblks)
	306	resblks -= XFS_IALLOC_SPACE_RES(mp);
	307	/*
	308	* If the symlink will fit into the inode, write it inline.
	309	*/
	310	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
	311	xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
	312	memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
	313	ip->i_d.di_size = pathlen;
	314
	315	/*
	316	* The inode was initially created in extent format.
	317	*/
	318	ip->i_df.if_flags &= ~(XFS_IFEXTENTS \| XFS_IFBROOT);
	319	ip->i_df.if_flags \|= XFS_IFINLINE;
	320
	321	ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
	322	xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA \| XFS_ILOG_CORE);
	323
	324	} else {
f948dd76 DC	325	int offset;
f948dd76 DC	326
19de7351 DC	327	first_fsb = 0;
	328	nmaps = XFS_SYMLINK_MAPS;
	329
	330	error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
	331	XFS_BMAPI_METADATA, &first_block, resblks,
	332	mval, &nmaps, &free_list);
	333	if (error)
	334	goto error2;
	335
	336	if (resblks)
	337	resblks -= fs_blocks;
	338	ip->i_d.di_size = pathlen;
	339	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	340
	341	cur_chunk = target_path;
f948dd76	342	offset = 0;
19de7351	343	for (n = 0; n < nmaps; n++) {
321a9583	344	char *buf;
f948dd76	345
19de7351 DC	346	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	347	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	348	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
	349	BTOBB(byte_cnt), 0);
	350	if (!bp) {
	351	error = ENOMEM;
	352	goto error2;
	353	}
f948dd76 DC	354	bp->b_ops = &xfs_symlink_buf_ops;
	355
	356	byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
321a9583	357	byte_cnt = min(byte_cnt, pathlen);
19de7351	358
f948dd76 DC	359	buf = bp->b_addr;
	360	buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
	361	byte_cnt, bp);
	362
	363	memcpy(buf, cur_chunk, byte_cnt);
	364
19de7351	365	cur_chunk += byte_cnt;
f948dd76 DC	366	pathlen -= byte_cnt;
f948dd76 DC	367	offset += byte_cnt;
19de7351	368
daf7b799	369	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
f948dd76 DC	370	xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
f948dd76 DC	371	(char *)bp->b_addr);
19de7351	372	}
321a9583	373	ASSERT(pathlen == 0);
19de7351 DC	374	}
	375
	376	/*
	377	* Create the directory entry for the symlink.
	378	*/
	379	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
	380	&first_block, &free_list, resblks);
	381	if (error)
	382	goto error2;
	383	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD \| XFS_ICHGTIME_CHG);
	384	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
	385
	386	/*
	387	* If this is a synchronous mount, make sure that the
	388	* symlink transaction goes to disk before returning to
	389	* the user.
	390	*/
	391	if (mp->m_flags & (XFS_MOUNT_WSYNC\|XFS_MOUNT_DIRSYNC)) {
	392	xfs_trans_set_sync(tp);
	393	}
	394
	395	error = xfs_bmap_finish(&tp, &free_list, &committed);
	396	if (error) {
	397	goto error2;
	398	}
	399	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
	400	xfs_qm_dqrele(udqp);
	401	xfs_qm_dqrele(gdqp);
92f8ff73	402	xfs_qm_dqrele(pdqp);
19de7351 DC	403
	404	*ipp = ip;
	405	return 0;
	406
	407	error2:
	408	IRELE(ip);
	409	error1:
	410	xfs_bmap_cancel(&free_list);
	411	cancel_flags \|= XFS_TRANS_ABORT;
	412	error_return:
	413	xfs_trans_cancel(tp, cancel_flags);
	414	xfs_qm_dqrele(udqp);
	415	xfs_qm_dqrele(gdqp);
92f8ff73	416	xfs_qm_dqrele(pdqp);
19de7351 DC	417
	418	if (unlock_dp_on_error)
	419	xfs_iunlock(dp, XFS_ILOCK_EXCL);
	420	std_return:
	421	return error;
	422	}
	423
	424	/*
	425	* Free a symlink that has blocks associated with it.
	426	*/
725eb1eb	427	STATIC int
19de7351	428	xfs_inactive_symlink_rmt(
36b21dde	429	struct xfs_inode *ip)
19de7351 DC	430	{
	431	xfs_buf_t *bp;
	432	int committed;
	433	int done;
	434	int error;
	435	xfs_fsblock_t first_block;
	436	xfs_bmap_free_t free_list;
	437	int i;
	438	xfs_mount_t *mp;
	439	xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
	440	int nmaps;
19de7351 DC	441	int size;
	442	xfs_trans_t *tp;
	443
19de7351	444	mp = ip->i_mount;
725eb1eb	445	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
19de7351 DC	446	/*
	447	* We're freeing a symlink that has some
	448	* blocks allocated to it. Free the
	449	* blocks here. We know that we've got
	450	* either 1 or 2 extents and that we can
	451	* free them all in one bunmapi call.
	452	*/
	453	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
	454
36b21dde BF	455	tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
	456	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
	457	if (error) {
	458	xfs_trans_cancel(tp, 0);
	459	return error;
	460	}
	461
	462	xfs_ilock(ip, XFS_ILOCK_EXCL);
	463	xfs_trans_ijoin(tp, ip, 0);
	464
19de7351 DC	465	/*
	466	* Lock the inode, fix the size, and join it to the transaction.
	467	* Hold it so in the normal path, we still have it locked for
	468	* the second transaction. In the error paths we need it
	469	* held so the cancel won't rele it, see below.
	470	*/
	471	size = (int)ip->i_d.di_size;
	472	ip->i_d.di_size = 0;
	473	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	474	/*
	475	* Find the block(s) so we can inval and unmap them.
	476	*/
	477	done = 0;
	478	xfs_bmap_init(&free_list, &first_block);
	479	nmaps = ARRAY_SIZE(mval);
f948dd76	480	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
19de7351 DC	481	mval, &nmaps, 0);
19de7351 DC	482	if (error)
36b21dde	483	goto error_trans_cancel;
19de7351	484	/*
f948dd76	485	* Invalidate the block(s). No validation is done.
19de7351 DC	486	*/
	487	for (i = 0; i < nmaps; i++) {
	488	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
	489	XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
	490	XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
	491	if (!bp) {
	492	error = ENOMEM;
36b21dde	493	goto error_bmap_cancel;
19de7351 DC	494	}
	495	xfs_trans_binval(tp, bp);
	496	}
	497	/*
	498	* Unmap the dead block(s) to the free_list.
	499	*/
36b21dde BF	500	error = xfs_bunmapi(tp, ip, 0, size, XFS_BMAPI_METADATA, nmaps,
	501	&first_block, &free_list, &done);
	502	if (error)
	503	goto error_bmap_cancel;
19de7351 DC	504	ASSERT(done);
	505	/*
	506	* Commit the first transaction. This logs the EFI and the inode.
	507	*/
36b21dde BF	508	error = xfs_bmap_finish(&tp, &free_list, &committed);
	509	if (error)
	510	goto error_bmap_cancel;
19de7351 DC	511	/*
	512	* The transaction must have been committed, since there were
	513	* actually extents freed by xfs_bunmapi. See xfs_bmap_finish.
	514	* The new tp has the extent freeing and EFDs.
	515	*/
	516	ASSERT(committed);
	517	/*
	518	* The first xact was committed, so add the inode to the new one.
	519	* Mark it dirty so it will be logged and moved forward in the log as
	520	* part of every commit.
	521	*/
	522	xfs_trans_ijoin(tp, ip, 0);
	523	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
19de7351 DC	524	/*
19de7351 DC	525	* Commit the transaction containing extent freeing and EFDs.
19de7351	526	*/
36b21dde	527	error = xfs_trans_commit(tp, XFS_TRANS_RELEASE_LOG_RES);
19de7351 DC	528	if (error) {
19de7351 DC	529	ASSERT(XFS_FORCED_SHUTDOWN(mp));
36b21dde	530	goto error_unlock;
19de7351	531	}
19de7351 DC	532
	533	/*
	534	* Remove the memory for extent descriptions (just bookkeeping).
	535	*/
	536	if (ip->i_df.if_bytes)
	537	xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
	538	ASSERT(ip->i_df.if_bytes == 0);
19de7351	539
36b21dde	540	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	541	return 0;
19de7351 DC	542
36b21dde	543	error_bmap_cancel:
19de7351	544	xfs_bmap_cancel(&free_list);
36b21dde BF	545	error_trans_cancel:
	546	xfs_trans_cancel(tp, XFS_TRANS_RELEASE_LOG_RES \| XFS_TRANS_ABORT);
	547	error_unlock:
	548	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	549	return error;
19de7351 DC	550	}
725eb1eb MT	551
	552	/*
	553	* xfs_inactive_symlink - free a symlink
	554	*/
	555	int
	556	xfs_inactive_symlink(
36b21dde	557	struct xfs_inode *ip)
725eb1eb MT	558	{
	559	struct xfs_mount *mp = ip->i_mount;
	560	int pathlen;
	561
	562	trace_xfs_inactive_symlink(ip);
	563
725eb1eb MT	564	if (XFS_FORCED_SHUTDOWN(mp))
	565	return XFS_ERROR(EIO);
	566
36b21dde BF	567	xfs_ilock(ip, XFS_ILOCK_EXCL);
36b21dde BF	568
725eb1eb MT	569	/*
	570	* Zero length symlinks _can_ exist.
	571	*/
	572	pathlen = (int)ip->i_d.di_size;
36b21dde BF	573	if (!pathlen) {
36b21dde BF	574	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb	575	return 0;
36b21dde	576	}
725eb1eb MT	577
	578	if (pathlen < 0 \|\| pathlen > MAXPATHLEN) {
	579	xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
	580	__func__, (unsigned long long)ip->i_ino, pathlen);
36b21dde	581	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb MT	582	ASSERT(0);
	583	return XFS_ERROR(EFSCORRUPTED);
	584	}
	585
	586	if (ip->i_df.if_flags & XFS_IFINLINE) {
36b21dde	587	if (ip->i_df.if_bytes > 0)
725eb1eb MT	588	xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
725eb1eb MT	589	XFS_DATA_FORK);
36b21dde	590	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb MT	591	ASSERT(ip->i_df.if_bytes == 0);
	592	return 0;
	593	}
	594
36b21dde BF	595	xfs_iunlock(ip, XFS_ILOCK_EXCL);
36b21dde BF	596
725eb1eb	597	/* remove the remote symlink */
36b21dde	598	return xfs_inactive_symlink_rmt(ip);
725eb1eb	599	}