// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2021-2024 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#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_trans_space.h"
#include "xfs_dir2.h"
#include "xfs_icache.h"
#include "xfs_bmap.h"
#include "xfs_bmap_btree.h"
#include "xfs_parent.h"
#include "xfs_attr_sf.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/repair.h"
#include "scrub/trace.h"
#include "scrub/orphanage.h"
#include "scrub/readdir.h"
#include <linux/namei.h>
/*
* The Orphanage
* =============
*
* If the directory tree is damaged, children of that directory become
* inaccessible via that file path. If a child has no other parents, the file
* is said to be orphaned. xfs_repair fixes this situation by creating a
* orphanage directory (specifically, /lost+found) and creating a directory
* entry pointing to the orphaned file.
*
* Online repair follows this tactic by creating a root-owned /lost+found
* directory if one does not exist. If an orphan is found, it will move that
* files into orphanage.
*/
/* Make the orphanage owned by root. */
STATIC int
xrep_chown_orphanage(
struct xfs_scrub *sc,
struct xfs_inode *dp)
{
struct xfs_trans *tp;
struct xfs_mount *mp = sc->mp;
struct xfs_dquot *udqp = NULL, *gdqp = NULL, *pdqp = NULL;
struct xfs_dquot *oldu = NULL, *oldg = NULL, *oldp = NULL;
struct inode *inode = VFS_I(dp);
int error;
error = xfs_qm_vop_dqalloc(dp, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, 0,
XFS_QMOPT_QUOTALL, &udqp, &gdqp, &pdqp);
if (error)
return error;
error = xfs_trans_alloc_ichange(dp, udqp, gdqp, pdqp, true, &tp);
if (error)
goto out_dqrele;
/*
* Always clear setuid/setgid/sticky on the orphanage since we don't
* normally want that functionality on this directory and xfs_repair
* doesn't create it this way either. Leave the other access bits
* unchanged.
*/
inode->i_mode &= ~(S_ISUID | S_ISGID | S_ISVTX);
/*
* Change the ownerships and register quota modifications
* in the transaction.
*/
if (!uid_eq(inode->i_uid, GLOBAL_ROOT_UID)) {
if (XFS_IS_UQUOTA_ON(mp))
oldu = xfs_qm_vop_chown(tp, dp, &dp->i_udquot, udqp);
inode->i_uid = GLOBAL_ROOT_UID;
}
if (!gid_eq(inode->i_gid, GLOBAL_ROOT_GID)) {
if (XFS_IS_GQUOTA_ON(mp))
oldg = xfs_qm_vop_chown(tp, dp, &dp->i_gdquot, gdqp);
inode->i_gid = GLOBAL_ROOT_GID;
}
if (dp->i_projid != 0) {
if (XFS_IS_PQUOTA_ON(mp))
oldp = xfs_qm_vop_chown(tp, dp, &dp->i_pdquot, pdqp);
dp->i_projid = 0;
}
dp->i_diflags &= ~(XFS_DIFLAG_REALTIME | XFS_DIFLAG_RTINHERIT);
xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
XFS_STATS_INC(mp, xs_ig_attrchg);
if (xfs_has_wsync(mp))
xfs_trans_set_sync(tp);
error = xfs_trans_commit(tp);
xfs_qm_dqrele(oldu);
xfs_qm_dqrele(oldg);
xfs_qm_dqrele(oldp);
out_dqrele:
xfs_qm_dqrele(udqp);
xfs_qm_dqrele(gdqp);
xfs_qm_dqrele(pdqp);
return error;
}
#define ORPHANAGE "lost+found"
/* Create the orphanage directory, and set sc->orphanage to it. */
int
xrep_orphanage_create(
struct xfs_scrub *sc)
{
struct xfs_mount *mp = sc->mp;
struct dentry *root_dentry, *orphanage_dentry;
struct inode *root_inode = VFS_I(sc->mp->m_rootip);
struct inode *orphanage_inode;
int error;
if (xfs_is_shutdown(mp))
return -EIO;
if (xfs_is_readonly(mp)) {
sc->orphanage = NULL;
return 0;
}
ASSERT(sc->tp == NULL);
ASSERT(sc->orphanage == NULL);
/* Find the dentry for the root directory... */
root_dentry = d_find_alias(root_inode);
if (!root_dentry) {
error = -EFSCORRUPTED;
goto out;
}
/* ...which is a directory, right? */
if (!d_is_dir(root_dentry)) {
error = -EFSCORRUPTED;
goto out_dput_root;
}
/* Try to find the orphanage directory. */
inode_lock_nested(root_inode, I_MUTEX_PARENT);
orphanage_dentry = lookup_one_len(ORPHANAGE, root_dentry,
strlen(ORPHANAGE));
if (IS_ERR(orphanage_dentry)) {
error = PTR_ERR(orphanage_dentry);
goto out_unlock_root;
}
/*
* Nothing found? Call mkdir to create the orphanage. Create the
* directory without other-user access because we're live and someone
* could have been relying partly on minimal access to a parent
* directory to control access to a file we put in here.
*/
if (d_really_is_negative(orphanage_dentry)) {
error = vfs_mkdir(&nop_mnt_idmap, root_inode, orphanage_dentry,
0750);
if (error)
goto out_dput_orphanage;
}
/* Not a directory? Bail out. */
if (!d_is_dir(orphanage_dentry)) {
error = -ENOTDIR;
goto out_dput_orphanage;
}
/*
* Grab a reference to the orphanage. This /should/ succeed since
* we hold the root directory locked and therefore nobody can delete
* the orphanage.
*/
orphanage_inode = igrab(d_inode(orphanage_dentry));
if (!orphanage_inode) {
error = -ENOENT;
goto out_dput_orphanage;
}
/* Make sure the orphanage is owned by root. */
error = xrep_chown_orphanage(sc, XFS_I(orphanage_inode));
if (error)
goto out_dput_orphanage;
/* Stash the reference for later and bail out. */
sc->orphanage = XFS_I(orphanage_inode);
sc->orphanage_ilock_flags = 0;
out_dput_orphanage:
dput(orphanage_dentry);
out_unlock_root:
inode_unlock(VFS_I(sc->mp->m_rootip));
out_dput_root:
dput(root_dentry);
out:
return error;
}
void
xrep_orphanage_ilock(
struct xfs_scrub *sc,
unsigned int ilock_flags)
{
sc->orphanage_ilock_flags |= ilock_flags;
xfs_ilock(sc->orphanage, ilock_flags);
}
bool
xrep_orphanage_ilock_nowait(
struct xfs_scrub *sc,
unsigned int ilock_flags)
{
if (xfs_ilock_nowait(sc->orphanage, ilock_flags)) {
sc->orphanage_ilock_flags |= ilock_flags;
return true;
}
return false;
}
void
xrep_orphanage_iunlock(
struct xfs_scrub *sc,
unsigned int ilock_flags)
{
xfs_iunlock(sc->orphanage, ilock_flags);
sc->orphanage_ilock_flags &= ~ilock_flags;
}
/* Grab the IOLOCK of the orphanage and sc->ip. */
int
xrep_orphanage_iolock_two(
struct xfs_scrub *sc)
{
int error = 0;
while (true) {
if (xchk_should_terminate(sc, &error))
return error;
/*
* Normal XFS takes the IOLOCK before grabbing a transaction.
* Scrub holds a transaction, which means that we can't block
* on either IOLOCK.
*/
if (xrep_orphanage_ilock_nowait(sc, XFS_IOLOCK_EXCL)) {
if (xchk_ilock_nowait(sc, XFS_IOLOCK_EXCL))
break;
xrep_orphanage_iunlock(sc, XFS_IOLOCK_EXCL);
}
delay(1);
}
return 0;
}
/* Release the orphanage. */
void
xrep_orphanage_rele(
struct xfs_scrub *sc)
{
if (!sc->orphanage)
return;
if (sc->orphanage_ilock_flags)
xfs_iunlock(sc->orphanage, sc->orphanage_ilock_flags);
xchk_irele(sc, sc->orphanage);
sc->orphanage = NULL;
}
/* Adoption moves a file into /lost+found */
/* Can the orphanage adopt @sc->ip? */
bool
xrep_orphanage_can_adopt(
struct xfs_scrub *sc)
{
ASSERT(sc->ip != NULL);
if (!sc->orphanage)
return false;
if (sc->ip == sc->orphanage)
return false;
if (xfs_internal_inum(sc->mp, sc->ip->i_ino))
return false;
return true;
}
/*
* Create a new transaction to send a child to the orphanage.
*
* Allocate a new transaction with sufficient disk space to handle the
* adoption, take ILOCK_EXCL of the orphanage and sc->ip, joins them to the
* transaction, and reserve quota to reparent the latter. Caller must hold the
* IOLOCK of the orphanage and sc->ip.
*/
int
xrep_adoption_trans_alloc(
struct xfs_scrub *sc,
struct xrep_adoption *adopt)
{
struct xfs_mount *mp = sc->mp;
unsigned int child_blkres = 0;
int error;
ASSERT(sc->tp == NULL);
ASSERT(sc->ip != NULL);
ASSERT(sc->orphanage != NULL);
ASSERT(sc->ilock_flags & XFS_IOLOCK_EXCL);
ASSERT(sc->orphanage_ilock_flags & XFS_IOLOCK_EXCL);
ASSERT(!(sc->ilock_flags & (XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)));
ASSERT(!(sc->orphanage_ilock_flags &
(XFS_ILOCK_SHARED | XFS_ILOCK_EXCL)));
/* Compute the worst case space reservation that we need. */
adopt->sc = sc;
adopt->orphanage_blkres = xfs_link_space_res(mp, MAXNAMELEN);
if (S_ISDIR(VFS_I(sc->ip)->i_mode))
child_blkres = xfs_rename_space_res(mp, 0, false,
xfs_name_dotdot.len, false);
if (xfs_has_parent(mp))
child_blkres += XFS_ADDAFORK_SPACE_RES(mp);
adopt->child_blkres = child_blkres;
/*
* Allocate a transaction to link the child into the parent, along with
* enough disk space to handle expansion of both the orphanage and the
* dotdot entry of a child directory.
*/
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link,
adopt->orphanage_blkres + adopt->child_blkres, 0, 0,
&sc->tp);
if (error)
return error;
xfs_lock_two_inodes(sc->orphanage, XFS_ILOCK_EXCL,
sc->ip, XFS_ILOCK_EXCL);
sc->ilock_flags |= XFS_ILOCK_EXCL;
sc->orphanage_ilock_flags |= XFS_ILOCK_EXCL;
xfs_trans_ijoin(sc->tp, sc->orphanage, 0);
xfs_trans_ijoin(sc->tp, sc->ip, 0);
/*
* Reserve enough quota in the orphan directory to add the new name.
* Normally the orphanage should have user/group/project ids of zero
* and hence is not subject to quota enforcement, but we're allowed to
* exceed quota to reattach disconnected parts of the directory tree.
*/
error = xfs_trans_reserve_quota_nblks(sc->tp, sc->orphanage,
adopt->orphanage_blkres, 0, true);
if (error)
goto out_cancel;
/*
* Reserve enough quota in the child directory to change dotdot.
* Here we're also allowed to exceed file quota to repair inconsistent
* metadata.
*/
if (adopt->child_blkres) {
error = xfs_trans_reserve_quota_nblks(sc->tp, sc->ip,
adopt->child_blkres, 0, true);
if (error)
goto out_cancel;
}
return 0;
out_cancel:
xchk_trans_cancel(sc);
xrep_orphanage_iunlock(sc, XFS_ILOCK_EXCL);
xchk_iunlock(sc, XFS_ILOCK_EXCL);
return error;
}
/*
* Compute the xfs_name for the directory entry that we're adding to the
* orphanage. Caller must hold ILOCKs of sc->ip and the orphanage and must not
* reuse namebuf until the adoption completes or is dissolved.
*/
int
xrep_adoption_compute_name(
struct xrep_adoption *adopt,
struct xfs_name *xname)
{
struct xfs_scrub *sc = adopt->sc;
char *namebuf = (void *)xname->name;
xfs_ino_t ino;
unsigned int incr = 0;
int error = 0;
adopt->xname = xname;
xname->len = snprintf(namebuf, MAXNAMELEN, "%llu", sc->ip->i_ino);
xname->type = xfs_mode_to_ftype(VFS_I(sc->ip)->i_mode);
/* Make sure the filename is unique in the lost+found. */
error = xchk_dir_lookup(sc, sc->orphanage, xname, &ino);
while (error == 0 && incr < 10000) {
xname->len = snprintf(namebuf, MAXNAMELEN, "%llu.%u",
sc->ip->i_ino, ++incr);
error = xchk_dir_lookup(sc, sc->orphanage, xname, &ino);
}
if (error == 0) {
/* We already have 10,000 entries in the orphanage? */
return -EFSCORRUPTED;
}
if (error != -ENOENT)
return error;
return 0;
}
/*
* Make sure the dcache does not have a positive dentry for the name we've
* chosen. The caller should have checked with the ondisk directory, so any
* discrepancy is a sign that something is seriously wrong.
*/
static int
xrep_adoption_check_dcache(
struct xrep_adoption *adopt)
{
struct qstr qname = QSTR_INIT(adopt->xname->name,
adopt->xname->len);
struct xfs_scrub *sc = adopt->sc;
struct dentry *d_orphanage, *d_child;
int error = 0;
d_orphanage = d_find_alias(VFS_I(sc->orphanage));
if (!d_orphanage)
return 0;
d_child = d_hash_and_lookup(d_orphanage, &qname);
if (d_child) {
trace_xrep_adoption_check_child(sc->mp, d_child);
if (d_is_positive(d_child)) {
ASSERT(d_is_negative(d_child));
error = -EFSCORRUPTED;
}
dput(d_child);
}
dput(d_orphanage);
return error;
}
/*
* Invalidate all dentries for the name that was added to the orphanage
* directory, and all dentries pointing to the child inode that was moved.
*
* There should not be any positive entries for the name, since we've
* maintained our lock on the orphanage directory.
*/
static void
xrep_adoption_zap_dcache(
struct xrep_adoption *adopt)
{
struct qstr qname = QSTR_INIT(adopt->xname->name,
adopt->xname->len);
struct xfs_scrub *sc = adopt->sc;
struct dentry *d_orphanage, *d_child;
/* Invalidate all dentries for the adoption name */
d_orphanage = d_find_alias(VFS_I(sc->orphanage));
if (!d_orphanage)
return;
d_child = d_hash_and_lookup(d_orphanage, &qname);
while (d_child != NULL) {
trace_xrep_adoption_invalidate_child(sc->mp, d_child);
ASSERT(d_is_negative(d_child));
d_invalidate(d_child);
dput(d_child);
d_child = d_lookup(d_orphanage, &qname);
}
dput(d_orphanage);
/* Invalidate all the dentries pointing down to this file. */
while ((d_child = d_find_alias(VFS_I(sc->ip))) != NULL) {
trace_xrep_adoption_invalidate_child(sc->mp, d_child);
d_invalidate(d_child);
dput(d_child);
}
}
/*
* If we have to add an attr fork ahead of a parent pointer update, how much
* space should we ask for?
*/
static inline int
xrep_adoption_attr_sizeof(
const struct xrep_adoption *adopt)
{
return sizeof(struct xfs_attr_sf_hdr) +
xfs_attr_sf_entsize_byname(sizeof(struct xfs_parent_rec),
adopt->xname->len);
}
/*
* Move the current file to the orphanage under the computed name.
*
* Returns with a dirty transaction so that the caller can handle any other
* work, such as fixing up unlinked lists or resetting link counts.
*/
int
xrep_adoption_move(
struct xrep_adoption *adopt)
{
struct xfs_scrub *sc = adopt->sc;
bool isdir = S_ISDIR(VFS_I(sc->ip)->i_mode);
int error;
trace_xrep_adoption_reparent(sc->orphanage, adopt->xname,
sc->ip->i_ino);
error = xrep_adoption_check_dcache(adopt);
if (error)
return error;
/*
* If this filesystem has parent pointers, ensure that the file being
* moved to the orphanage has an attribute fork. This is required
* because the parent pointer code does not itself add attr forks.
*/
if (!xfs_inode_has_attr_fork(sc->ip) && xfs_has_parent(sc->mp)) {
int sf_size = xrep_adoption_attr_sizeof(adopt);
error = xfs_bmap_add_attrfork(sc->tp, sc->ip, sf_size, true);
if (error)
return error;
}
/* Create the new name in the orphanage. */
error = xfs_dir_createname(sc->tp, sc->orphanage, adopt->xname,
sc->ip->i_ino, adopt->orphanage_blkres);
if (error)
return error;
/*
* Bump the link count of the orphanage if we just added a
* subdirectory, and update its timestamps.
*/
xfs_trans_ichgtime(sc->tp, sc->orphanage,
XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
if (isdir)
xfs_bumplink(sc->tp, sc->orphanage);
xfs_trans_log_inode(sc->tp, sc->orphanage, XFS_ILOG_CORE);
/* Bump the link count of the child. */
if (adopt->bump_child_nlink) {
xfs_bumplink(sc->tp, sc->ip);
xfs_trans_log_inode(sc->tp, sc->ip, XFS_ILOG_CORE);
}
/* Replace the dotdot entry if the child is a subdirectory. */
if (isdir) {
error = xfs_dir_replace(sc->tp, sc->ip, &xfs_name_dotdot,
sc->orphanage->i_ino, adopt->child_blkres);
if (error)
return error;
}
/* Add a parent pointer from the file back to the lost+found. */
if (xfs_has_parent(sc->mp)) {
error = xfs_parent_addname(sc->tp, &adopt->ppargs,
sc->orphanage, adopt->xname, sc->ip);
if (error)
return error;
}
/*
* Notify dirent hooks that we moved the file to /lost+found, and
* finish all the deferred work so that we know the adoption is fully
* recorded in the log.
*/
xfs_dir_update_hook(sc->orphanage, sc->ip, 1, adopt->xname);
/* Remove negative dentries from the lost+found's dcache */
xrep_adoption_zap_dcache(adopt);
return 0;
}
/*
* Roll to a clean scrub transaction so that we can release the orphanage,
* even if xrep_adoption_move was not called.
*
* Commits all the work and deferred ops attached to an adoption request and
* rolls to a clean scrub transaction. On success, returns 0 with the scrub
* context holding a clean transaction with no inodes joined. On failure,
* returns negative errno with no scrub transaction. All inode locks are
* still held after this function returns.
*/
int
xrep_adoption_trans_roll(
struct xrep_adoption *adopt)
{
struct xfs_scrub *sc = adopt->sc;
int error;
trace_xrep_adoption_trans_roll(sc->orphanage, sc->ip,
!!(sc->tp->t_flags & XFS_TRANS_DIRTY));
/* Finish all the deferred ops to commit all repairs. */
error = xrep_defer_finish(sc);
if (error)
return error;
/* Roll the transaction once more to detach the inodes. */
return xfs_trans_roll(&sc->tp);
}
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