// 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"
#include "xfs_health.h"
#include "xfs_symlink_remote.h"
#include "xfs_parent.h"
#include "xfs_defer.h"
int
xfs_readlink(
struct xfs_inode *ip,
char *link)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fsize_t pathlen;
int error;
trace_xfs_readlink(ip);
if (xfs_is_shutdown(mp))
return -EIO;
if (xfs_ifork_zapped(ip, XFS_DATA_FORK))
return -EIO;
xfs_ilock(ip, XFS_ILOCK_SHARED);
pathlen = ip->i_disk_size;
if (!pathlen)
goto out_corrupt;
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_corrupt;
}
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_data))
goto out_corrupt;
memcpy(link, ip->i_df.if_data, pathlen + 1);
error = 0;
} else {
error = xfs_symlink_remote_read(ip, link);
}
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return error;
out_corrupt:
xfs_iunlock(ip, XFS_ILOCK_SHARED);
xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
return -EFSCORRUPTED;
}
int
xfs_symlink(
struct mnt_idmap *idmap,
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_icreate_args args = {
.idmap = idmap,
.pip = dp,
.mode = S_IFLNK | (mode & ~S_IFMT),
};
struct xfs_dir_update du = {
.dp = dp,
.name = link_name,
};
struct xfs_trans *tp = NULL;
int error = 0;
int pathlen;
bool unlock_dp_on_error = false;
xfs_filblks_t fs_blocks;
struct xfs_dquot *udqp;
struct xfs_dquot *gdqp;
struct xfs_dquot *pdqp;
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);
/* Make sure that we have allocated dquot(s) on disk. */
error = xfs_icreate_dqalloc(&args, &udqp, &gdqp, &pdqp);
if (error)
return error;
/*
* The symlink will fit into the inode data fork?
* If there are no parent pointers, then there wont't be any attributes.
* So we get the whole variable part, and do not need to reserve extra
* blocks. Otherwise, we need to reserve the blocks.
*/
if (pathlen <= XFS_LITINO(mp) && !xfs_has_parent(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_parent_start(mp, &du.ppargs);
if (error)
goto out_release_dquots;
error = xfs_trans_alloc_icreate(mp, &M_RES(mp)->tr_symlink, udqp, gdqp,
pdqp, resblks, &tp);
if (error)
goto out_parent;
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, &args, &ino);
if (!error)
error = xfs_icreate(tp, ino, &args, &du.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, 0);
/*
* Also attach the dquot(s) to it, if applicable.
*/
xfs_qm_vop_create_dqattach(tp, du.ip, udqp, gdqp, pdqp);
resblks -= XFS_IALLOC_SPACE_RES(mp);
error = xfs_symlink_write_target(tp, du.ip, du.ip->i_ino, target_path,
pathlen, fs_blocks, resblks);
if (error)
goto out_trans_cancel;
resblks -= fs_blocks;
i_size_write(VFS_I(du.ip), du.ip->i_disk_size);
/*
* Create the directory entry for the symlink.
*/
error = xfs_dir_create_child(tp, resblks, &du);
if (error)
goto out_trans_cancel;
/*
* 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 = du.ip;
xfs_iunlock(du.ip, XFS_ILOCK_EXCL);
xfs_iunlock(dp, XFS_ILOCK_EXCL);
xfs_parent_finish(mp, du.ppargs);
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 (du.ip) {
xfs_iunlock(du.ip, XFS_ILOCK_EXCL);
xfs_finish_inode_setup(du.ip);
xfs_irele(du.ip);
}
out_parent:
xfs_parent_finish(mp, du.ppargs);
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_mount *mp = ip->i_mount;
struct xfs_trans *tp;
int error;
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.
*/
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);
error = xfs_symlink_remote_truncate(tp, ip);
if (error)
goto error_trans_cancel;
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);
xfs_inode_mark_sick(ip, XFS_SICK_INO_SYMLINK);
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);
}
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