[linux-2.6-block.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_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.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"

/* ----- 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 -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(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, cur_chunk, 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 -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 = -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;
	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 -EIO;

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

	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
	/*
	 * 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)
		goto out_trans_cancel;

	xfs_ilock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL |
		      XFS_IOLOCK_PARENT | 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 = -EPERM;
		goto out_trans_cancel;
	}

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

	/*
	 * Check for ability to enter directory entry, if no space reserved.
	 */
	if (!resblks) {
		error = xfs_dir_canenter(tp, dp, link_name);
		if (error)
			goto out_trans_cancel;
	}
	/*
	 * 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)
		goto out_trans_cancel;

	/*
	 * Now we join the directory inode to the transaction.  We do not do it
	 * earlier because xfs_dir_ialloc might commit the previous transaction
	 * (and release all the locks).  An error from here on will result in
	 * the transaction cancel unlocking dp so don't do it explicitly in the
	 * error path.
	 */
	xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL | 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 out_bmap_cancel;

		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 out_bmap_cancel;
			}
			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 out_bmap_cancel;
	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, NULL);
	if (error)
		goto out_bmap_cancel;

	error = xfs_trans_commit(tp);
	if (error)
		goto out_release_inode;

	xfs_qm_dqrele(udqp);
	xfs_qm_dqrele(gdqp);
	xfs_qm_dqrele(pdqp);

	*ipp = ip;
	return 0;

out_bmap_cancel:
	xfs_bmap_cancel(&free_list);
out_trans_cancel:
	xfs_trans_cancel(tp);
out_release_inode:
	/*
	 * Wait until after the current transaction is aborted to finish the
	 * setup of the inode and release the inode.  This prevents recursive
	 * transactions and deadlocks from xfs_inactive.
	 */
	if (ip) {
		xfs_finish_inode_setup(ip);
		IRELE(ip);
	}

	xfs_qm_dqrele(udqp);
	xfs_qm_dqrele(gdqp);
	xfs_qm_dqrele(pdqp);

	if (unlock_dp_on_error)
		xfs_iunlock(dp, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);
	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		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);
		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, 0, 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, ip);
	if (error)
		goto error_bmap_cancel;
	/*
	 * 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);
	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);
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 -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 -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	26	#include "xfs_mount.h"
57062787	27	#include "xfs_da_format.h"
d6cf1305	28	#include "xfs_da_btree.h"
2b9ab5ab	29	#include "xfs_dir2.h"
19de7351	30	#include "xfs_inode.h"
19de7351 DC	31	#include "xfs_ialloc.h"
	32	#include "xfs_alloc.h"
	33	#include "xfs_bmap.h"
a4fbe6ab	34	#include "xfs_bmap_btree.h"
68988114	35	#include "xfs_bmap_util.h"
19de7351 DC	36	#include "xfs_error.h"
19de7351 DC	37	#include "xfs_quota.h"
19de7351	38	#include "xfs_trans_space.h"
19de7351 DC	39	#include "xfs_trace.h"
19de7351 DC	40	#include "xfs_symlink.h"
239880ef	41	#include "xfs_trans.h"
239880ef	42	#include "xfs_log.h"
19de7351 DC	43
19de7351 DC	44	/* ----- Kernel only functions below ----- */
19de7351 DC	45	STATIC int
19de7351 DC	46	xfs_readlink_bmap(
f948dd76 DC	47	struct xfs_inode *ip,
f948dd76 DC	48	char *link)
19de7351	49	{
f948dd76 DC	50	struct xfs_mount *mp = ip->i_mount;
	51	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
	52	struct xfs_buf *bp;
	53	xfs_daddr_t d;
	54	char *cur_chunk;
	55	int pathlen = ip->i_d.di_size;
	56	int nmaps = XFS_SYMLINK_MAPS;
	57	int byte_cnt;
	58	int n;
	59	int error = 0;
	60	int fsblocks = 0;
	61	int offset;
19de7351	62
f948dd76 DC	63	fsblocks = xfs_symlink_blocks(mp, pathlen);
f948dd76 DC	64	error = xfs_bmapi_read(ip, 0, fsblocks, mval, &nmaps, 0);
19de7351 DC	65	if (error)
	66	goto out;
	67
f948dd76	68	offset = 0;
19de7351 DC	69	for (n = 0; n < nmaps; n++) {
	70	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	71	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	72
f948dd76 DC	73	bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
f948dd76 DC	74	&xfs_symlink_buf_ops);
19de7351	75	if (!bp)
2451337d	76	return -ENOMEM;
19de7351 DC	77	error = bp->b_error;
	78	if (error) {
	79	xfs_buf_ioerror_alert(bp, __func__);
	80	xfs_buf_relse(bp);
ac75a1f7 DC	81
ac75a1f7 DC	82	/* bad CRC means corrupted metadata */
2451337d DC	83	if (error == -EFSBADCRC)
2451337d DC	84	error = -EFSCORRUPTED;
19de7351 DC	85	goto out;
19de7351 DC	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)) {
bda65ef8	93	if (!xfs_symlink_hdr_ok(ip->i_ino, offset,
f948dd76	94	byte_cnt, bp)) {
2451337d	95	error = -EFSCORRUPTED;
f948dd76 DC	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
2ac56d3d	107	memcpy(link + offset, cur_chunk, byte_cnt);
f948dd76	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))
2451337d	135	return -EIO;
19de7351 DC	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);
2451337d	148	error = -EFSCORRUPTED;
19de7351 DC	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;
58c90473	180	bool unlock_dp_on_error = false;
19de7351 DC	181	xfs_fileoff_t first_fsb;
	182	xfs_filblks_t fs_blocks;
	183	int nmaps;
f948dd76	184	struct xfs_bmbt_irec mval[XFS_SYMLINK_MAPS];
19de7351 DC	185	xfs_daddr_t d;
	186	const char *cur_chunk;
	187	int byte_cnt;
	188	int n;
	189	xfs_buf_t *bp;
	190	prid_t prid;
113a5683 CS	191	struct xfs_dquot *udqp = NULL;
113a5683 CS	192	struct xfs_dquot *gdqp = NULL;
92f8ff73	193	struct xfs_dquot *pdqp = NULL;
19de7351 DC	194	uint resblks;
	195
	196	*ipp = NULL;
19de7351 DC	197
	198	trace_xfs_symlink(dp, link_name);
	199
	200	if (XFS_FORCED_SHUTDOWN(mp))
2451337d	201	return -EIO;
19de7351 DC	202
	203	/*
	204	* Check component lengths of the target path name.
	205	*/
	206	pathlen = strlen(target_path);
	207	if (pathlen >= MAXPATHLEN) /* total string too long */
2451337d	208	return -ENAMETOOLONG;
19de7351 DC	209
19de7351 DC	210	udqp = gdqp = NULL;
163467d3	211	prid = xfs_get_initial_prid(dp);
19de7351 DC	212
	213	/*
	214	* Make sure that we have allocated dquot(s) on disk.
	215	*/
7aab1b28 DE	216	error = xfs_qm_vop_dqalloc(dp,
	217	xfs_kuid_to_uid(current_fsuid()),
	218	xfs_kgid_to_gid(current_fsgid()), prid,
	219	XFS_QMOPT_QUOTALL \| XFS_QMOPT_INHERIT,
	220	&udqp, &gdqp, &pdqp);
19de7351	221	if (error)
58c90473	222	return error;
19de7351 DC	223
19de7351 DC	224	tp = xfs_trans_alloc(mp, XFS_TRANS_SYMLINK);
19de7351 DC	225	/*
	226	* The symlink will fit into the inode data fork?
	227	* There can't be any attributes so we get the whole variable part.
	228	*/
	229	if (pathlen <= XFS_LITINO(mp, dp->i_d.di_version))
	230	fs_blocks = 0;
	231	else
321a9583	232	fs_blocks = xfs_symlink_blocks(mp, pathlen);
19de7351	233	resblks = XFS_SYMLINK_SPACE_RES(mp, link_name->len, fs_blocks);
3d3c8b52	234	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, resblks, 0);
2451337d	235	if (error == -ENOSPC && fs_blocks == 0) {
19de7351	236	resblks = 0;
3d3c8b52	237	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_symlink, 0, 0);
19de7351	238	}
4906e215	239	if (error)
58c90473	240	goto out_trans_cancel;
19de7351	241
dbad7c99 DC	242	xfs_ilock(dp, XFS_IOLOCK_EXCL \| XFS_ILOCK_EXCL \|
dbad7c99 DC	243	XFS_IOLOCK_PARENT \| XFS_ILOCK_PARENT);
19de7351 DC	244	unlock_dp_on_error = true;
	245
	246	/*
	247	* Check whether the directory allows new symlinks or not.
	248	*/
	249	if (dp->i_d.di_flags & XFS_DIFLAG_NOSYMLINKS) {
2451337d	250	error = -EPERM;
58c90473	251	goto out_trans_cancel;
19de7351 DC	252	}
	253
	254	/*
	255	* Reserve disk quota : blocks and inode.
	256	*/
92f8ff73 CS	257	error = xfs_trans_reserve_quota(tp, mp, udqp, gdqp,
92f8ff73 CS	258	pdqp, resblks, 1, 0);
19de7351	259	if (error)
58c90473	260	goto out_trans_cancel;
19de7351 DC	261
	262	/*
	263	* Check for ability to enter directory entry, if no space reserved.
	264	*/
94f3cad5 ES	265	if (!resblks) {
	266	error = xfs_dir_canenter(tp, dp, link_name);
	267	if (error)
58c90473	268	goto out_trans_cancel;
94f3cad5	269	}
19de7351 DC	270	/*
	271	* Initialize the bmap freelist prior to calling either
	272	* bmapi or the directory create code.
	273	*/
	274	xfs_bmap_init(&free_list, &first_block);
	275
	276	/*
	277	* Allocate an inode for the symlink.
	278	*/
	279	error = xfs_dir_ialloc(&tp, dp, S_IFLNK \| (mode & ~S_IFMT), 1, 0,
	280	prid, resblks > 0, &ip, NULL);
58c90473 DC	281	if (error)
58c90473 DC	282	goto out_trans_cancel;
19de7351 DC	283
19de7351 DC	284	/*
58c90473 DC	285	* Now we join the directory inode to the transaction. We do not do it
	286	* earlier because xfs_dir_ialloc might commit the previous transaction
	287	* (and release all the locks). An error from here on will result in
	288	* the transaction cancel unlocking dp so don't do it explicitly in the
19de7351 DC	289	* error path.
19de7351 DC	290	*/
dbad7c99	291	xfs_trans_ijoin(tp, dp, XFS_IOLOCK_EXCL \| XFS_ILOCK_EXCL);
19de7351 DC	292	unlock_dp_on_error = false;
	293
	294	/*
	295	* Also attach the dquot(s) to it, if applicable.
	296	*/
92f8ff73	297	xfs_qm_vop_create_dqattach(tp, ip, udqp, gdqp, pdqp);
19de7351 DC	298
	299	if (resblks)
	300	resblks -= XFS_IALLOC_SPACE_RES(mp);
	301	/*
	302	* If the symlink will fit into the inode, write it inline.
	303	*/
	304	if (pathlen <= XFS_IFORK_DSIZE(ip)) {
	305	xfs_idata_realloc(ip, pathlen, XFS_DATA_FORK);
	306	memcpy(ip->i_df.if_u1.if_data, target_path, pathlen);
	307	ip->i_d.di_size = pathlen;
	308
	309	/*
	310	* The inode was initially created in extent format.
	311	*/
	312	ip->i_df.if_flags &= ~(XFS_IFEXTENTS \| XFS_IFBROOT);
	313	ip->i_df.if_flags \|= XFS_IFINLINE;
	314
	315	ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
	316	xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA \| XFS_ILOG_CORE);
	317
	318	} else {
f948dd76 DC	319	int offset;
f948dd76 DC	320
19de7351 DC	321	first_fsb = 0;
	322	nmaps = XFS_SYMLINK_MAPS;
	323
	324	error = xfs_bmapi_write(tp, ip, first_fsb, fs_blocks,
	325	XFS_BMAPI_METADATA, &first_block, resblks,
	326	mval, &nmaps, &free_list);
	327	if (error)
58c90473	328	goto out_bmap_cancel;
19de7351 DC	329
	330	if (resblks)
	331	resblks -= fs_blocks;
	332	ip->i_d.di_size = pathlen;
	333	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	334
	335	cur_chunk = target_path;
f948dd76	336	offset = 0;
19de7351	337	for (n = 0; n < nmaps; n++) {
321a9583	338	char *buf;
f948dd76	339
19de7351 DC	340	d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
	341	byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
	342	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
	343	BTOBB(byte_cnt), 0);
	344	if (!bp) {
2451337d	345	error = -ENOMEM;
58c90473	346	goto out_bmap_cancel;
19de7351	347	}
f948dd76 DC	348	bp->b_ops = &xfs_symlink_buf_ops;
	349
	350	byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
321a9583	351	byte_cnt = min(byte_cnt, pathlen);
19de7351	352
f948dd76 DC	353	buf = bp->b_addr;
	354	buf += xfs_symlink_hdr_set(mp, ip->i_ino, offset,
	355	byte_cnt, bp);
	356
	357	memcpy(buf, cur_chunk, byte_cnt);
	358
19de7351	359	cur_chunk += byte_cnt;
f948dd76 DC	360	pathlen -= byte_cnt;
f948dd76 DC	361	offset += byte_cnt;
19de7351	362
daf7b799	363	xfs_trans_buf_set_type(tp, bp, XFS_BLFT_SYMLINK_BUF);
f948dd76 DC	364	xfs_trans_log_buf(tp, bp, 0, (buf + byte_cnt - 1) -
f948dd76 DC	365	(char *)bp->b_addr);
19de7351	366	}
321a9583	367	ASSERT(pathlen == 0);
19de7351 DC	368	}
	369
	370	/*
	371	* Create the directory entry for the symlink.
	372	*/
	373	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino,
	374	&first_block, &free_list, resblks);
	375	if (error)
58c90473	376	goto out_bmap_cancel;
19de7351 DC	377	xfs_trans_ichgtime(tp, dp, XFS_ICHGTIME_MOD \| XFS_ICHGTIME_CHG);
	378	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
	379
	380	/*
	381	* If this is a synchronous mount, make sure that the
	382	* symlink transaction goes to disk before returning to
	383	* the user.
	384	*/
	385	if (mp->m_flags & (XFS_MOUNT_WSYNC\|XFS_MOUNT_DIRSYNC)) {
	386	xfs_trans_set_sync(tp);
	387	}
	388
f6106efa	389	error = xfs_bmap_finish(&tp, &free_list, NULL);
58c90473 DC	390	if (error)
	391	goto out_bmap_cancel;
	392
70393313	393	error = xfs_trans_commit(tp);
58c90473 DC	394	if (error)
	395	goto out_release_inode;
	396
19de7351 DC	397	xfs_qm_dqrele(udqp);
19de7351 DC	398	xfs_qm_dqrele(gdqp);
92f8ff73	399	xfs_qm_dqrele(pdqp);
19de7351 DC	400
	401	*ipp = ip;
	402	return 0;
	403
58c90473	404	out_bmap_cancel:
19de7351	405	xfs_bmap_cancel(&free_list);
58c90473	406	out_trans_cancel:
4906e215	407	xfs_trans_cancel(tp);
58c90473 DC	408	out_release_inode:
	409	/*
	410	* Wait until after the current transaction is aborted to finish the
	411	* setup of the inode and release the inode. This prevents recursive
	412	* transactions and deadlocks from xfs_inactive.
	413	*/
	414	if (ip) {
	415	xfs_finish_inode_setup(ip);
	416	IRELE(ip);
	417	}
	418
19de7351 DC	419	xfs_qm_dqrele(udqp);
19de7351 DC	420	xfs_qm_dqrele(gdqp);
92f8ff73	421	xfs_qm_dqrele(pdqp);
19de7351 DC	422
19de7351 DC	423	if (unlock_dp_on_error)
dbad7c99	424	xfs_iunlock(dp, XFS_IOLOCK_EXCL \| XFS_ILOCK_EXCL);
19de7351 DC	425	return error;
	426	}
	427
	428	/*
	429	* Free a symlink that has blocks associated with it.
	430	*/
725eb1eb	431	STATIC int
19de7351	432	xfs_inactive_symlink_rmt(
36b21dde	433	struct xfs_inode *ip)
19de7351 DC	434	{
19de7351 DC	435	xfs_buf_t *bp;
19de7351 DC	436	int done;
	437	int error;
	438	xfs_fsblock_t first_block;
	439	xfs_bmap_free_t free_list;
	440	int i;
	441	xfs_mount_t *mp;
	442	xfs_bmbt_irec_t mval[XFS_SYMLINK_MAPS];
	443	int nmaps;
19de7351 DC	444	int size;
	445	xfs_trans_t *tp;
	446
19de7351	447	mp = ip->i_mount;
725eb1eb	448	ASSERT(ip->i_df.if_flags & XFS_IFEXTENTS);
19de7351 DC	449	/*
	450	* We're freeing a symlink that has some
	451	* blocks allocated to it. Free the
	452	* blocks here. We know that we've got
	453	* either 1 or 2 extents and that we can
	454	* free them all in one bunmapi call.
	455	*/
	456	ASSERT(ip->i_d.di_nextents > 0 && ip->i_d.di_nextents <= 2);
	457
36b21dde BF	458	tp = xfs_trans_alloc(mp, XFS_TRANS_INACTIVE);
	459	error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
	460	if (error) {
4906e215	461	xfs_trans_cancel(tp);
36b21dde BF	462	return error;
	463	}
	464
	465	xfs_ilock(ip, XFS_ILOCK_EXCL);
	466	xfs_trans_ijoin(tp, ip, 0);
	467
19de7351 DC	468	/*
	469	* Lock the inode, fix the size, and join it to the transaction.
	470	* Hold it so in the normal path, we still have it locked for
	471	* the second transaction. In the error paths we need it
	472	* held so the cancel won't rele it, see below.
	473	*/
	474	size = (int)ip->i_d.di_size;
	475	ip->i_d.di_size = 0;
	476	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
	477	/*
	478	* Find the block(s) so we can inval and unmap them.
	479	*/
	480	done = 0;
	481	xfs_bmap_init(&free_list, &first_block);
	482	nmaps = ARRAY_SIZE(mval);
f948dd76	483	error = xfs_bmapi_read(ip, 0, xfs_symlink_blocks(mp, size),
19de7351 DC	484	mval, &nmaps, 0);
19de7351 DC	485	if (error)
36b21dde	486	goto error_trans_cancel;
19de7351	487	/*
f948dd76	488	* Invalidate the block(s). No validation is done.
19de7351 DC	489	*/
	490	for (i = 0; i < nmaps; i++) {
	491	bp = xfs_trans_get_buf(tp, mp->m_ddev_targp,
	492	XFS_FSB_TO_DADDR(mp, mval[i].br_startblock),
	493	XFS_FSB_TO_BB(mp, mval[i].br_blockcount), 0);
	494	if (!bp) {
2451337d	495	error = -ENOMEM;
36b21dde	496	goto error_bmap_cancel;
19de7351 DC	497	}
	498	xfs_trans_binval(tp, bp);
	499	}
	500	/*
	501	* Unmap the dead block(s) to the free_list.
	502	*/
ab7bb610	503	error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps,
36b21dde BF	504	&first_block, &free_list, &done);
	505	if (error)
	506	goto error_bmap_cancel;
19de7351 DC	507	ASSERT(done);
	508	/*
	509	* Commit the first transaction. This logs the EFI and the inode.
	510	*/
f6106efa	511	error = xfs_bmap_finish(&tp, &free_list, ip);
36b21dde BF	512	if (error)
36b21dde BF	513	goto error_bmap_cancel;
19de7351 DC	514	/*
	515	* The first xact was committed, so add the inode to the new one.
	516	* Mark it dirty so it will be logged and moved forward in the log as
	517	* part of every commit.
	518	*/
	519	xfs_trans_ijoin(tp, ip, 0);
	520	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
19de7351 DC	521	/*
19de7351 DC	522	* Commit the transaction containing extent freeing and EFDs.
19de7351	523	*/
70393313	524	error = xfs_trans_commit(tp);
19de7351 DC	525	if (error) {
19de7351 DC	526	ASSERT(XFS_FORCED_SHUTDOWN(mp));
36b21dde	527	goto error_unlock;
19de7351	528	}
19de7351 DC	529
	530	/*
	531	* Remove the memory for extent descriptions (just bookkeeping).
	532	*/
	533	if (ip->i_df.if_bytes)
	534	xfs_idata_realloc(ip, -ip->i_df.if_bytes, XFS_DATA_FORK);
	535	ASSERT(ip->i_df.if_bytes == 0);
19de7351	536
36b21dde	537	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	538	return 0;
19de7351 DC	539
36b21dde	540	error_bmap_cancel:
19de7351	541	xfs_bmap_cancel(&free_list);
36b21dde	542	error_trans_cancel:
4906e215	543	xfs_trans_cancel(tp);
36b21dde BF	544	error_unlock:
36b21dde BF	545	xfs_iunlock(ip, XFS_ILOCK_EXCL);
19de7351 DC	546	return error;
19de7351 DC	547	}
725eb1eb MT	548
	549	/*
	550	* xfs_inactive_symlink - free a symlink
	551	*/
	552	int
	553	xfs_inactive_symlink(
36b21dde	554	struct xfs_inode *ip)
725eb1eb MT	555	{
	556	struct xfs_mount *mp = ip->i_mount;
	557	int pathlen;
	558
	559	trace_xfs_inactive_symlink(ip);
	560
725eb1eb	561	if (XFS_FORCED_SHUTDOWN(mp))
2451337d	562	return -EIO;
725eb1eb	563
36b21dde BF	564	xfs_ilock(ip, XFS_ILOCK_EXCL);
36b21dde BF	565
725eb1eb MT	566	/*
	567	* Zero length symlinks _can_ exist.
	568	*/
	569	pathlen = (int)ip->i_d.di_size;
36b21dde BF	570	if (!pathlen) {
36b21dde BF	571	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb	572	return 0;
36b21dde	573	}
725eb1eb MT	574
	575	if (pathlen < 0 \|\| pathlen > MAXPATHLEN) {
	576	xfs_alert(mp, "%s: inode (0x%llx) bad symlink length (%d)",
	577	__func__, (unsigned long long)ip->i_ino, pathlen);
36b21dde	578	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb	579	ASSERT(0);
2451337d	580	return -EFSCORRUPTED;
725eb1eb MT	581	}
	582
	583	if (ip->i_df.if_flags & XFS_IFINLINE) {
36b21dde	584	if (ip->i_df.if_bytes > 0)
725eb1eb MT	585	xfs_idata_realloc(ip, -(ip->i_df.if_bytes),
725eb1eb MT	586	XFS_DATA_FORK);
36b21dde	587	xfs_iunlock(ip, XFS_ILOCK_EXCL);
725eb1eb MT	588	ASSERT(ip->i_df.if_bytes == 0);
	589	return 0;
	590	}
	591
36b21dde BF	592	xfs_iunlock(ip, XFS_ILOCK_EXCL);
36b21dde BF	593
725eb1eb	594	/* remove the remote symlink */
36b21dde	595	return xfs_inactive_symlink_rmt(ip);
725eb1eb	596	}