Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 512 insertions, 0 deletions

diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c
new file mode 100644
index 000000000..8389f3ef8
--- /dev/null
+++ b/fs/xfs/xfs_symlink.c
@@ -0,0 +1,512 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * Copyright (c) 2012-2013 Red Hat, Inc.
+ * All rights reserved.
+ */
+#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_dir2.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_quota.h"
+#include "xfs_symlink.h"
+#include "xfs_trans_space.h"
+#include "xfs_trace.h"
+#include "xfs_trans.h"
+#include "xfs_ialloc.h"
+#include "xfs_error.h"
+
+/* ----- Kernel only functions below ----- */
+int
+xfs_readlink_bmap_ilocked(
+	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_disk_size;
+	int			nmaps = XFS_SYMLINK_MAPS;
+	int			byte_cnt;
+	int			n;
+	int			error = 0;
+	int			fsblocks = 0;
+	int			offset;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
+
+	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);
+
+		error = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0,
+				&bp, &xfs_symlink_buf_ops);
+		if (error)
+			return error;
+		byte_cnt = XFS_SYMLINK_BUF_SPACE(mp, byte_cnt);
+		if (pathlen < byte_cnt)
+			byte_cnt = pathlen;
+
+		cur_chunk = bp->b_addr;
+		if (xfs_has_crc(mp)) {
+			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_disk_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 = -EFSCORRUPTED;
+
+	trace_xfs_readlink(ip);
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	xfs_ilock(ip, XFS_ILOCK_SHARED);
+
+	pathlen = ip->i_disk_size;
+	if (!pathlen)
+		goto out;
+
+	if (pathlen < 0 || pathlen > XFS_SYMLINK_MAXLEN) {
+		xfs_alert(mp, "%s: inode (%llu) bad symlink length (%lld)",
+			 __func__, (unsigned long long) ip->i_ino,
+			 (long long) pathlen);
+		ASSERT(0);
+		goto out;
+	}
+
+	if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
+		/*
+		 * The VFS crashes on a NULL pointer, so return -EFSCORRUPTED
+		 * if if_data is junk.
+		 */
+		if (XFS_IS_CORRUPT(ip->i_mount, !ip->i_df.if_u1.if_data))
+			goto out;
+
+		memcpy(link, ip->i_df.if_u1.if_data, pathlen + 1);
+		error = 0;
+	} else {
+		error = xfs_readlink_bmap_ilocked(ip, link);
+	}
+
+ out:
+	xfs_iunlock(ip, XFS_ILOCK_SHARED);
+	return error;
+}
+
+int
+xfs_symlink(
+	struct user_namespace	*mnt_userns,
+	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;
+	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;
+	struct xfs_buf		*bp;
+	prid_t			prid;
+	struct xfs_dquot	*udqp = NULL;
+	struct xfs_dquot	*gdqp = NULL;
+	struct xfs_dquot	*pdqp = NULL;
+	uint			resblks;
+	xfs_ino_t		ino;
+
+	*ipp = NULL;
+
+	trace_xfs_symlink(dp, link_name);
+
+	if (xfs_is_shutdown(mp))
+		return -EIO;
+
+	/*
+	 * Check component lengths of the target path name.
+	 */
+	pathlen = strlen(target_path);
+	if (pathlen >= XFS_SYMLINK_MAXLEN)      /* total string too long */
+		return -ENAMETOOLONG;
+	ASSERT(pathlen > 0);
+
+	prid = xfs_get_initial_prid(dp);
+
+	/*
+	 * Make sure that we have allocated dquot(s) on disk.
+	 */
+	error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns),
+			mapped_fsgid(mnt_userns, &init_user_ns), prid,
+			XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT,
+			&udqp, &gdqp, &pdqp);
+	if (error)
+		return error;
+
+	/*
+	 * 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))
+		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_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
+			pdqp, resblks, &tp);
+	if (error)
+		goto out_release_dquots;
+
+	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_diflags & XFS_DIFLAG_NOSYMLINKS) {
+		error = -EPERM;
+		goto out_trans_cancel;
+	}
+
+	/*
+	 * Allocate an inode for the symlink.
+	 */
+	error = xfs_dialloc(&tp, dp->i_ino, S_IFLNK, &ino);
+	if (!error)
+		error = xfs_init_new_inode(mnt_userns, tp, dp, ino,
+				S_IFLNK | (mode & ~S_IFMT), 1, 0, prid,
+				false, &ip);
+	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_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);
+
+	resblks -= XFS_IALLOC_SPACE_RES(mp);
+	/*
+	 * If the symlink will fit into the inode, write it inline.
+	 */
+	if (pathlen <= xfs_inode_data_fork_size(ip)) {
+		xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
+
+		ip->i_disk_size = pathlen;
+		ip->i_df.if_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, resblks, mval, &nmaps);
+		if (error)
+			goto out_trans_cancel;
+
+		resblks -= fs_blocks;
+		ip->i_disk_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);
+			error = xfs_trans_get_buf(tp, mp->m_ddev_targp, d,
+					       BTOBB(byte_cnt), 0, &bp);
+			if (error)
+				goto out_trans_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);
+	}
+	i_size_write(VFS_I(ip), ip->i_disk_size);
+
+	/*
+	 * Create the directory entry for the symlink.
+	 */
+	error = xfs_dir_createname(tp, dp, link_name, ip->i_ino, resblks);
+	if (error)
+		goto out_trans_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 (xfs_has_wsync(mp) || xfs_has_dirsync(mp))
+		xfs_trans_set_sync(tp);
+
+	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_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);
+		xfs_irele(ip);
+	}
+out_release_dquots:
+	xfs_qm_dqrele(udqp);
+	xfs_qm_dqrele(gdqp);
+	xfs_qm_dqrele(pdqp);
+
+	if (unlock_dp_on_error)
+		xfs_iunlock(dp, XFS_ILOCK_EXCL);
+	return error;
+}
+
+/*
+ * Free a symlink that has blocks associated with it.
+ *
+ * Note: zero length symlinks are not allowed to exist. When we set the size to
+ * zero, also change it to a regular file so that it does not get written to
+ * disk as a zero length symlink. The inode is on the unlinked list already, so
+ * userspace cannot find this inode anymore, so this change is not user visible
+ * but allows us to catch corrupt zero-length symlinks in the verifiers.
+ */
+STATIC int
+xfs_inactive_symlink_rmt(
+	struct xfs_inode *ip)
+{
+	struct xfs_buf	*bp;
+	int		done;
+	int		error;
+	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(!xfs_need_iread_extents(&ip->i_df));
+	/*
+	 * 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_df.if_nextents > 0 && ip->i_df.if_nextents <= 2);
+
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	if (error)
+		return error;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, ip, 0);
+
+	/*
+	 * Lock the inode, fix the size, turn it into a regular file 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_disk_size;
+	ip->i_disk_size = 0;
+	VFS_I(ip)->i_mode = (VFS_I(ip)->i_mode & ~S_IFMT) | S_IFREG;
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+	/*
+	 * Find the block(s) so we can inval and unmap them.
+	 */
+	done = 0;
+	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++) {
+		error = 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,
+				&bp);
+		if (error)
+			goto error_trans_cancel;
+		xfs_trans_binval(tp, bp);
+	}
+	/*
+	 * Unmap the dead block(s) to the dfops.
+	 */
+	error = xfs_bunmapi(tp, ip, 0, size, 0, nmaps, &done);
+	if (error)
+		goto error_trans_cancel;
+	ASSERT(done);
+
+	/*
+	 * Commit the transaction. This first logs the EFI and the inode, then
+	 * rolls and commits the transaction that frees the extents.
+	 */
+	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
+	error = xfs_trans_commit(tp);
+	if (error) {
+		ASSERT(xfs_is_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_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_is_shutdown(mp))
+		return -EIO;
+
+	xfs_ilock(ip, XFS_ILOCK_EXCL);
+	pathlen = (int)ip->i_disk_size;
+	ASSERT(pathlen);
+
+	if (pathlen <= 0 || pathlen > XFS_SYMLINK_MAXLEN) {
+		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;
+	}
+
+	/*
+	 * Inline fork state gets removed by xfs_difree() so we have nothing to
+	 * do here in that case.
+	 */
+	if (ip->i_df.if_format == XFS_DINODE_FMT_LOCAL) {
+		xfs_iunlock(ip, XFS_ILOCK_EXCL);
+		return 0;
+	}
+
+	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+
+	/* remove the remote symlink */
+	return xfs_inactive_symlink_rmt(ip);
+}