Fixed MTP to work with TWRP

fs/xfs/xfs_symlink.c

@@ -0,0 +1,601 @@
+/*
+ * 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_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"
+#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 -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, 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 -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;
+	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 -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)
+		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 = -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.
+	 */
+	if (!resblks) {
+		error = xfs_dir_canenter(tp, dp, link_name);
+		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 -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);
+}