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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_ialloc.h"
#include "xfs_quota.h"
#include "xfs_bmap_btree.h"
#include "xfs_trans_space.h"
#include "xfs_dir2.h"
#include "xfs_xchgrange.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/tempfile.h"
/*
* Create a temporary file for reconstructing metadata, with the intention of
* atomically swapping the temporary file's contents with the file that's
* being repaired.
*/
int
xrep_tempfile_create(
struct xfs_scrub *sc,
uint16_t mode)
{
struct xfs_mount *mp = sc->mp;
struct xfs_trans *tp = NULL;
struct xfs_dquot *udqp = NULL;
struct xfs_dquot *gdqp = NULL;
struct xfs_dquot *pdqp = NULL;
struct xfs_trans_res *tres;
struct xfs_inode *dp = mp->m_rootip;
xfs_ino_t ino;
unsigned int resblks;
bool is_dir = S_ISDIR(mode);
int error;
if (xfs_is_shutdown(mp))
return -EIO;
if (xfs_is_readonly(mp))
return -EROFS;
ASSERT(sc->tp == NULL);
ASSERT(sc->tempip == NULL);
/*
* Make sure that we have allocated dquot(s) on disk. The temporary
* inode should be completely root owned so that we don't fail due to
* quota limits.
*/
error = xfs_qm_vop_dqalloc(dp, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 0,
XFS_QMOPT_QUOTALL, &udqp, &gdqp, &pdqp);
if (error)
return error;
if (is_dir) {
resblks = XFS_MKDIR_SPACE_RES(mp, 0);
tres = &M_RES(mp)->tr_mkdir;
} else {
resblks = XFS_IALLOC_SPACE_RES(mp);
tres = &M_RES(mp)->tr_create_tmpfile;
}
error = xfs_trans_alloc_icreate(mp, tres, udqp, gdqp, pdqp, resblks,
&tp);
if (error)
goto out_release_dquots;
/* Allocate inode, set up directory. */
error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
if (error)
goto out_trans_cancel;
error = xfs_init_new_inode(&init_user_ns, tp, dp, ino, mode, 0, 0,
0, false, &sc->tempip);
if (error)
goto out_trans_cancel;
/* Change the ownership of the inode to root. */
VFS_I(sc->tempip)->i_uid = GLOBAL_ROOT_UID;
VFS_I(sc->tempip)->i_gid = GLOBAL_ROOT_GID;
sc->tempip->i_diflags &= ~(XFS_DIFLAG_REALTIME | XFS_DIFLAG_RTINHERIT);
xfs_trans_log_inode(tp, sc->tempip, XFS_ILOG_CORE);
/*
* Mark our temporary file as private so that LSMs and the ACL code
* don't try to add their own metadata or reason about these files.
* The file should never be exposed to userspace.
*/
VFS_I(sc->tempip)->i_flags |= S_PRIVATE;
VFS_I(sc->tempip)->i_opflags &= ~IOP_XATTR;
if (is_dir) {
error = xfs_dir_init(tp, sc->tempip, dp);
if (error)
goto out_trans_cancel;
}
/*
* Attach the dquot(s) to the inodes and modify them incore.
* These ids of the inode couldn't have changed since the new
* inode has been locked ever since it was created.
*/
xfs_qm_vop_create_dqattach(tp, sc->tempip, udqp, gdqp, pdqp);
/*
* Put our temp file on the unlinked list so it's purged automatically.
* Anything being reconstructed using this file must be atomically
* swapped with the original file because the contents here will be
* purged when the inode is dropped or log recovery cleans out the
* unlinked list.
*/
error = xfs_iunlink(tp, sc->tempip);
if (error)
goto out_trans_cancel;
error = xfs_trans_commit(tp);
if (error)
goto out_release_inode;
trace_xrep_tempfile_create(sc);
xfs_qm_dqrele(udqp);
xfs_qm_dqrele(gdqp);
xfs_qm_dqrele(pdqp);
/* Finish setting up the incore / vfs context. */
xfs_setup_iops(sc->tempip);
xfs_finish_inode_setup(sc->tempip);
sc->temp_ilock_flags = 0;
return error;
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 (sc->tempip) {
xfs_finish_inode_setup(sc->tempip);
xchk_irele(sc, sc->tempip);
}
out_release_dquots:
xfs_qm_dqrele(udqp);
xfs_qm_dqrele(gdqp);
xfs_qm_dqrele(pdqp);
return error;
}
/* Take IOLOCK_EXCL on the temporary file, maybe. */
bool
xrep_tempfile_iolock_nowait(
struct xfs_scrub *sc)
{
if (xfs_ilock_nowait(sc->tempip, XFS_IOLOCK_EXCL)) {
sc->temp_ilock_flags |= XFS_IOLOCK_EXCL;
return true;
}
return false;
}
/* Release IOLOCK_EXCL on the temporary file. */
void
xrep_tempfile_iounlock(
struct xfs_scrub *sc)
{
xfs_iunlock(sc->tempip, XFS_IOLOCK_EXCL);
sc->temp_ilock_flags &= ~XFS_IOLOCK_EXCL;
}
/* Prepare the temporary file for metadata updates by grabbing ILOCK_EXCL. */
void
xrep_tempfile_ilock(
struct xfs_scrub *sc)
{
sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
xfs_ilock(sc->tempip, XFS_ILOCK_EXCL);
}
/* Try to grab ILOCK_EXCL on the temporary file. */
bool
xrep_tempfile_ilock_nowait(
struct xfs_scrub *sc)
{
if (xfs_ilock_nowait(sc->tempip, XFS_ILOCK_EXCL)) {
sc->temp_ilock_flags |= XFS_ILOCK_EXCL;
return true;
}
return false;
}
/* Unlock ILOCK_EXCL on the temporary file after an update. */
void
xrep_tempfile_iunlock(
struct xfs_scrub *sc)
{
xfs_iunlock(sc->tempip, XFS_ILOCK_EXCL);
sc->temp_ilock_flags &= ~XFS_ILOCK_EXCL;
}
/* Release the temporary file. */
void
xrep_tempfile_rele(
struct xfs_scrub *sc)
{
if (!sc->tempip)
return;
if (sc->temp_ilock_flags) {
xfs_iunlock(sc->tempip, sc->temp_ilock_flags);
sc->temp_ilock_flags = 0;
}
xchk_irele(sc, sc->tempip);
sc->tempip = NULL;
}
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