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 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * This file is part of UBIFS.
  *
  * Copyright (C) 2006-2008 Nokia Corporation.
  *
  * Author: Adrian Hunter
  */
 
 #include "ubifs.h"
 
 /*
  * An orphan is an inode number whose inode node has been committed to the index
  * with a link count of zero. That happens when an open file is deleted
  * (unlinked) and then a commit is run. In the normal course of events the inode
  * would be deleted when the file is closed. However in the case of an unclean
  * unmount, orphans need to be accounted for. After an unclean unmount, the
  * orphans' inodes must be deleted which means either scanning the entire index
  * looking for them, or keeping a list on flash somewhere. This unit implements
  * the latter approach.
  *
  * The orphan area is a fixed number of LEBs situated between the LPT area and
  * the main area. The number of orphan area LEBs is specified when the file
  * system is created. The minimum number is 1. The size of the orphan area
  * should be so that it can hold the maximum number of orphans that are expected
  * to ever exist at one time.
  *
  * The number of orphans that can fit in a LEB is:
  *
  *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
  *
  * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
  *
  * Orphans are accumulated in a rb-tree. When an inode's link count drops to
  * zero, the inode number is added to the rb-tree. It is removed from the tree
  * when the inode is deleted.  Any new orphans that are in the orphan tree when
  * the commit is run, are written to the orphan area in 1 or more orphan nodes.
  * If the orphan area is full, it is consolidated to make space.  There is
  * always enough space because validation prevents the user from creating more
  * than the maximum number of orphans allowed.
  */
 
 static int dbg_check_orphans(struct ubifs_info *c);
 
 static struct ubifs_orphan *orphan_add(struct ubifs_info *c, ino_t inum,
                        struct ubifs_orphan *parent_orphan)
 {
     struct ubifs_orphan *orphan, *o;
     struct rb_node **p, *parent = NULL;
 
     orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
     if (!orphan)
         return ERR_PTR(-ENOMEM);
     orphan->inum = inum;
     orphan->new = 1;
     INIT_LIST_HEAD(&orphan->child_list);
 
     spin_lock(&c->orphan_lock);
     if (c->tot_orphans >= c->max_orphans) {
         spin_unlock(&c->orphan_lock);
         kfree(orphan);
         return ERR_PTR(-ENFILE);
     }
     p = &c->orph_tree.rb_node;
     while (*p) {
         parent = *p;
         o = rb_entry(parent, struct ubifs_orphan, rb);
         if (inum < o->inum)
             p = &(*p)->rb_left;
         else if (inum > o->inum)
             p = &(*p)->rb_right;
         else {
             ubifs_err(c, "orphaned twice");
             spin_unlock(&c->orphan_lock);
             kfree(orphan);
             return ERR_PTR(-EINVAL);
         }
     }
     c->tot_orphans += 1;
     c->new_orphans += 1;
     rb_link_node(&orphan->rb, parent, p);
     rb_insert_color(&orphan->rb, &c->orph_tree);
     list_add_tail(&orphan->list, &c->orph_list);
     list_add_tail(&orphan->new_list, &c->orph_new);
 
     if (parent_orphan) {
         list_add_tail(&orphan->child_list,
                   &parent_orphan->child_list);
     }
 
     spin_unlock(&c->orphan_lock);
     dbg_gen("ino %lu", (unsigned long)inum);
     return orphan;
 }
 
 static struct ubifs_orphan *lookup_orphan(struct ubifs_info *c, ino_t inum)
 {
     struct ubifs_orphan *o;
     struct rb_node *p;
 
     p = c->orph_tree.rb_node;
     while (p) {
         o = rb_entry(p, struct ubifs_orphan, rb);
         if (inum < o->inum)
             p = p->rb_left;
         else if (inum > o->inum)
             p = p->rb_right;
         else {
             return o;
         }
     }
     return NULL;
 }
 
 static void __orphan_drop(struct ubifs_info *c, struct ubifs_orphan *o)
 {
     rb_erase(&o->rb, &c->orph_tree);
     list_del(&o->list);
     c->tot_orphans -= 1;
 
     if (o->new) {
         list_del(&o->new_list);
         c->new_orphans -= 1;
     }
 
     kfree(o);
 }
 
 static void orphan_delete(struct ubifs_info *c, struct ubifs_orphan *orph)
 {
     if (orph->del) {
         dbg_gen("deleted twice ino %lu", (unsigned long)orph->inum);
         return;
     }
 
     if (orph->cmt) {
         orph->del = 1;
         orph->dnext = c->orph_dnext;
         c->orph_dnext = orph;
         dbg_gen("delete later ino %lu", (unsigned long)orph->inum);
         return;
     }
 
     __orphan_drop(c, orph);
 }
 
 /**
  * ubifs_add_orphan - add an orphan.
  * @c: UBIFS file-system description object
  * @inum: orphan inode number
  *
  * Add an orphan. This function is called when an inodes link count drops to
  * zero.
  */
 int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
 {
     int err = 0;
     ino_t xattr_inum;
     union ubifs_key key;
     struct ubifs_dent_node *xent, *pxent = NULL;
     struct fscrypt_name nm = {0};
     struct ubifs_orphan *xattr_orphan;
     struct ubifs_orphan *orphan;
 
     orphan = orphan_add(c, inum, NULL);
     if (IS_ERR(orphan))
         return PTR_ERR(orphan);
 
     lowest_xent_key(c, &key, inum);
     while (1) {
         xent = ubifs_tnc_next_ent(c, &key, &nm);
         if (IS_ERR(xent)) {
             err = PTR_ERR(xent);
             if (err == -ENOENT)
                 break;
             kfree(pxent);
             return err;
         }
 
         fname_name(&nm) = xent->name;
         fname_len(&nm) = le16_to_cpu(xent->nlen);
         xattr_inum = le64_to_cpu(xent->inum);
 
         xattr_orphan = orphan_add(c, xattr_inum, orphan);
         if (IS_ERR(xattr_orphan)) {
             kfree(pxent);
             kfree(xent);
             return PTR_ERR(xattr_orphan);
         }
 
         kfree(pxent);
         pxent = xent;
         key_read(c, &xent->key, &key);
     }
     kfree(pxent);
 
     return 0;
 }
 
 /**
  * ubifs_delete_orphan - delete an orphan.
  * @c: UBIFS file-system description object
  * @inum: orphan inode number
  *
  * Delete an orphan. This function is called when an inode is deleted.
  */
 void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
 {
     struct ubifs_orphan *orph, *child_orph, *tmp_o;
 
     spin_lock(&c->orphan_lock);
 
     orph = lookup_orphan(c, inum);
     if (!orph) {
         spin_unlock(&c->orphan_lock);
         ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
         dump_stack();
 
         return;
     }
 
     list_for_each_entry_safe(child_orph, tmp_o, &orph->child_list, child_list) {
         list_del(&child_orph->child_list);
         orphan_delete(c, child_orph);
     }
     
     orphan_delete(c, orph);
 
     spin_unlock(&c->orphan_lock);
 }
 
 /**
  * ubifs_orphan_start_commit - start commit of orphans.
  * @c: UBIFS file-system description object
  *
  * Start commit of orphans.
  */
 int ubifs_orphan_start_commit(struct ubifs_info *c)
 {
     struct ubifs_orphan *orphan, **last;
 
     spin_lock(&c->orphan_lock);
     last = &c->orph_cnext;
     list_for_each_entry(orphan, &c->orph_new, new_list) {
         ubifs_assert(c, orphan->new);
         ubifs_assert(c, !orphan->cmt);
         orphan->new = 0;
         orphan->cmt = 1;
         *last = orphan;
         last = &orphan->cnext;
     }
     *last = NULL;
     c->cmt_orphans = c->new_orphans;
     c->new_orphans = 0;
     dbg_cmt("%d orphans to commit", c->cmt_orphans);
     INIT_LIST_HEAD(&c->orph_new);
     if (c->tot_orphans == 0)
         c->no_orphs = 1;
     else
         c->no_orphs = 0;
     spin_unlock(&c->orphan_lock);
     return 0;
 }
 
 /**
  * avail_orphs - calculate available space.
  * @c: UBIFS file-system description object
  *
  * This function returns the number of orphans that can be written in the
  * available space.
  */
 static int avail_orphs(struct ubifs_info *c)
 {
     int avail_lebs, avail, gap;
 
     avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
     avail = avail_lebs *
            ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
     gap = c->leb_size - c->ohead_offs;
     if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
         avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
     return avail;
 }
 
 /**
  * tot_avail_orphs - calculate total space.
  * @c: UBIFS file-system description object
  *
  * This function returns the number of orphans that can be written in half
  * the total space. That leaves half the space for adding new orphans.
  */
 static int tot_avail_orphs(struct ubifs_info *c)
 {
     int avail_lebs, avail;
 
     avail_lebs = c->orph_lebs;
     avail = avail_lebs *
            ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
     return avail / 2;
 }
 
 /**
  * do_write_orph_node - write a node to the orphan head.
  * @c: UBIFS file-system description object
  * @len: length of node
  * @atomic: write atomically
  *
  * This function writes a node to the orphan head from the orphan buffer. If
  * %atomic is not zero, then the write is done atomically. On success, %0 is
  * returned, otherwise a negative error code is returned.
  */
 static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
 {
     int err = 0;
 
     if (atomic) {
         ubifs_assert(c, c->ohead_offs == 0);
         ubifs_prepare_node(c, c->orph_buf, len, 1);
         len = ALIGN(len, c->min_io_size);
         err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
     } else {
         if (c->ohead_offs == 0) {
             /* Ensure LEB has been unmapped */
             err = ubifs_leb_unmap(c, c->ohead_lnum);
             if (err)
                 return err;
         }
         err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
                        c->ohead_offs);
     }
     return err;
 }
 
 /**
  * write_orph_node - write an orphan node.
  * @c: UBIFS file-system description object
  * @atomic: write atomically
  *
  * This function builds an orphan node from the cnext list and writes it to the
  * orphan head. On success, %0 is returned, otherwise a negative error code
  * is returned.
  */
 static int write_orph_node(struct ubifs_info *c, int atomic)
 {
     struct ubifs_orphan *orphan, *cnext;
     struct ubifs_orph_node *orph;
     int gap, err, len, cnt, i;
 
     ubifs_assert(c, c->cmt_orphans > 0);
     gap = c->leb_size - c->ohead_offs;
     if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
         c->ohead_lnum += 1;
         c->ohead_offs = 0;
         gap = c->leb_size;
         if (c->ohead_lnum > c->orph_last) {
             /*
              * We limit the number of orphans so that this should
              * never happen.
              */
             ubifs_err(c, "out of space in orphan area");
             return -EINVAL;
         }
     }
     cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
     if (cnt > c->cmt_orphans)
         cnt = c->cmt_orphans;
     len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
     ubifs_assert(c, c->orph_buf);
     orph = c->orph_buf;
     orph->ch.node_type = UBIFS_ORPH_NODE;
     spin_lock(&c->orphan_lock);
     cnext = c->orph_cnext;
     for (i = 0; i < cnt; i++) {
         orphan = cnext;
         ubifs_assert(c, orphan->cmt);
         orph->inos[i] = cpu_to_le64(orphan->inum);
         orphan->cmt = 0;
         cnext = orphan->cnext;
         orphan->cnext = NULL;
     }
     c->orph_cnext = cnext;
     c->cmt_orphans -= cnt;
     spin_unlock(&c->orphan_lock);
     if (c->cmt_orphans)
         orph->cmt_no = cpu_to_le64(c->cmt_no);
     else
         /* Mark the last node of the commit */
         orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
     ubifs_assert(c, c->ohead_offs + len <= c->leb_size);
     ubifs_assert(c, c->ohead_lnum >= c->orph_first);
     ubifs_assert(c, c->ohead_lnum <= c->orph_last);
     err = do_write_orph_node(c, len, atomic);
     c->ohead_offs += ALIGN(len, c->min_io_size);
     c->ohead_offs = ALIGN(c->ohead_offs, 8);
     return err;
 }
 
 /**
  * write_orph_nodes - write orphan nodes until there are no more to commit.
  * @c: UBIFS file-system description object
  * @atomic: write atomically
  *
  * This function writes orphan nodes for all the orphans to commit. On success,
  * %0 is returned, otherwise a negative error code is returned.
  */
 static int write_orph_nodes(struct ubifs_info *c, int atomic)
 {
     int err;
 
     while (c->cmt_orphans > 0) {
         err = write_orph_node(c, atomic);
         if (err)
             return err;
     }
     if (atomic) {
         int lnum;
 
         /* Unmap any unused LEBs after consolidation */
         for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
             err = ubifs_leb_unmap(c, lnum);
             if (err)
                 return err;
         }
     }
     return 0;
 }
 
 /**
  * consolidate - consolidate the orphan area.
  * @c: UBIFS file-system description object
  *
  * This function enables consolidation by putting all the orphans into the list
  * to commit. The list is in the order that the orphans were added, and the
  * LEBs are written atomically in order, so at no time can orphans be lost by
  * an unclean unmount.
  *
  * This function returns %0 on success and a negative error code on failure.
  */
 static int consolidate(struct ubifs_info *c)
 {
     int tot_avail = tot_avail_orphs(c), err = 0;
 
     spin_lock(&c->orphan_lock);
     dbg_cmt("there is space for %d orphans and there are %d",
         tot_avail, c->tot_orphans);
     if (c->tot_orphans - c->new_orphans <= tot_avail) {
         struct ubifs_orphan *orphan, **last;
         int cnt = 0;
 
         /* Change the cnext list to include all non-new orphans */
         last = &c->orph_cnext;
         list_for_each_entry(orphan, &c->orph_list, list) {
             if (orphan->new)
                 continue;
             orphan->cmt = 1;
             *last = orphan;
             last = &orphan->cnext;
             cnt += 1;
         }
         *last = NULL;
         ubifs_assert(c, cnt == c->tot_orphans - c->new_orphans);
         c->cmt_orphans = cnt;
         c->ohead_lnum = c->orph_first;
         c->ohead_offs = 0;
     } else {
         /*
          * We limit the number of orphans so that this should
          * never happen.
          */
         ubifs_err(c, "out of space in orphan area");
         err = -EINVAL;
     }
     spin_unlock(&c->orphan_lock);
     return err;
 }
 
 /**
  * commit_orphans - commit orphans.
  * @c: UBIFS file-system description object
  *
  * This function commits orphans to flash. On success, %0 is returned,
  * otherwise a negative error code is returned.
  */
 static int commit_orphans(struct ubifs_info *c)
 {
     int avail, atomic = 0, err;
 
     ubifs_assert(c, c->cmt_orphans > 0);
     avail = avail_orphs(c);
     if (avail < c->cmt_orphans) {
         /* Not enough space to write new orphans, so consolidate */
         err = consolidate(c);
         if (err)
             return err;
         atomic = 1;
     }
     err = write_orph_nodes(c, atomic);
     return err;
 }
 
 /**
  * erase_deleted - erase the orphans marked for deletion.
  * @c: UBIFS file-system description object
  *
  * During commit, the orphans being committed cannot be deleted, so they are
  * marked for deletion and deleted by this function. Also, the recovery
  * adds killed orphans to the deletion list, and therefore they are deleted
  * here too.
  */
 static void erase_deleted(struct ubifs_info *c)
 {
     struct ubifs_orphan *orphan, *dnext;
 
     spin_lock(&c->orphan_lock);
     dnext = c->orph_dnext;
     while (dnext) {
         orphan = dnext;
         dnext = orphan->dnext;
         ubifs_assert(c, !orphan->new);
         ubifs_assert(c, orphan->del);
         rb_erase(&orphan->rb, &c->orph_tree);
         list_del(&orphan->list);
         c->tot_orphans -= 1;
         dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
         kfree(orphan);
     }
     c->orph_dnext = NULL;
     spin_unlock(&c->orphan_lock);
 }
 
 /**
  * ubifs_orphan_end_commit - end commit of orphans.
  * @c: UBIFS file-system description object
  *
  * End commit of orphans.
  */
 int ubifs_orphan_end_commit(struct ubifs_info *c)
 {
     int err;
 
     if (c->cmt_orphans != 0) {
         err = commit_orphans(c);
         if (err)
             return err;
     }
     erase_deleted(c);
     err = dbg_check_orphans(c);
     return err;
 }
 
 /**
  * ubifs_clear_orphans - erase all LEBs used for orphans.
  * @c: UBIFS file-system description object
  *
  * If recovery is not required, then the orphans from the previous session
  * are not needed. This function locates the LEBs used to record
  * orphans, and un-maps them.
  */
 int ubifs_clear_orphans(struct ubifs_info *c)
 {
     int lnum, err;
 
     for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
         err = ubifs_leb_unmap(c, lnum);
         if (err)
             return err;
     }
     c->ohead_lnum = c->orph_first;
     c->ohead_offs = 0;
     return 0;
 }
 
 /**
  * insert_dead_orphan - insert an orphan.
  * @c: UBIFS file-system description object
  * @inum: orphan inode number
  *
  * This function is a helper to the 'do_kill_orphans()' function. The orphan
  * must be kept until the next commit, so it is added to the rb-tree and the
  * deletion list.
  */
 static int insert_dead_orphan(struct ubifs_info *c, ino_t inum)
 {
     struct ubifs_orphan *orphan, *o;
     struct rb_node **p, *parent = NULL;
 
     orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_KERNEL);
     if (!orphan)
         return -ENOMEM;
     orphan->inum = inum;
 
     p = &c->orph_tree.rb_node;
     while (*p) {
         parent = *p;
         o = rb_entry(parent, struct ubifs_orphan, rb);
         if (inum < o->inum)
             p = &(*p)->rb_left;
         else if (inum > o->inum)
             p = &(*p)->rb_right;
         else {
             /* Already added - no problem */
             kfree(orphan);
             return 0;
         }
     }
     c->tot_orphans += 1;
     rb_link_node(&orphan->rb, parent, p);
     rb_insert_color(&orphan->rb, &c->orph_tree);
     list_add_tail(&orphan->list, &c->orph_list);
     orphan->del = 1;
     orphan->dnext = c->orph_dnext;
     c->orph_dnext = orphan;
     dbg_mnt("ino %lu, new %d, tot %d", (unsigned long)inum,
         c->new_orphans, c->tot_orphans);
     return 0;
 }
 
 /**
  * do_kill_orphans - remove orphan inodes from the index.
  * @c: UBIFS file-system description object
  * @sleb: scanned LEB
  * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
  * @outofdate: whether the LEB is out of date is returned here
  * @last_flagged: whether the end orphan node is encountered
  *
  * This function is a helper to the 'kill_orphans()' function. It goes through
  * every orphan node in a LEB and for every inode number recorded, removes
  * all keys for that inode from the TNC.
  */
 static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
                unsigned long long *last_cmt_no, int *outofdate,
                int *last_flagged)
 {
     struct ubifs_scan_node *snod;
     struct ubifs_orph_node *orph;
     struct ubifs_ino_node *ino = NULL;
     unsigned long long cmt_no;
     ino_t inum;
     int i, n, err, first = 1;
 
     ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
     if (!ino)
         return -ENOMEM;
 
     list_for_each_entry(snod, &sleb->nodes, list) {
         if (snod->type != UBIFS_ORPH_NODE) {
             ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
                   snod->type, sleb->lnum, snod->offs);
             ubifs_dump_node(c, snod->node,
                     c->leb_size - snod->offs);
             err = -EINVAL;
             goto out_free;
         }
 
         orph = snod->node;
 
         /* Check commit number */
         cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
         /*
          * The commit number on the master node may be less, because
          * of a failed commit. If there are several failed commits in a
          * row, the commit number written on orphan nodes will continue
          * to increase (because the commit number is adjusted here) even
          * though the commit number on the master node stays the same
          * because the master node has not been re-written.
          */
         if (cmt_no > c->cmt_no)
             c->cmt_no = cmt_no;
         if (cmt_no < *last_cmt_no && *last_flagged) {
             /*
              * The last orphan node had a higher commit number and
              * was flagged as the last written for that commit
              * number. That makes this orphan node, out of date.
              */
             if (!first) {
                 ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
                       cmt_no, sleb->lnum, snod->offs);
                 ubifs_dump_node(c, snod->node,
                         c->leb_size - snod->offs);
                 err = -EINVAL;
                 goto out_free;
             }
             dbg_rcvry("out of date LEB %d", sleb->lnum);
             *outofdate = 1;
             err = 0;
             goto out_free;
         }
 
         if (first)
             first = 0;
 
         n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
         for (i = 0; i < n; i++) {
             union ubifs_key key1, key2;
 
             inum = le64_to_cpu(orph->inos[i]);
 
             ino_key_init(c, &key1, inum);
             err = ubifs_tnc_lookup(c, &key1, ino);
             if (err && err != -ENOENT)
                 goto out_free;
 
             /*
              * Check whether an inode can really get deleted.
              * linkat() with O_TMPFILE allows rebirth of an inode.
              */
             if (err == 0 && ino->nlink == 0) {
                 dbg_rcvry("deleting orphaned inode %lu",
                       (unsigned long)inum);
 
                 lowest_ino_key(c, &key1, inum);
                 highest_ino_key(c, &key2, inum);
 
                 err = ubifs_tnc_remove_range(c, &key1, &key2);
                 if (err)
                     goto out_ro;
             }
 
             err = insert_dead_orphan(c, inum);
             if (err)
                 goto out_free;
         }
 
         *last_cmt_no = cmt_no;
         if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
             dbg_rcvry("last orph node for commit %llu at %d:%d",
                   cmt_no, sleb->lnum, snod->offs);
             *last_flagged = 1;
         } else
             *last_flagged = 0;
     }
 
     err = 0;
 out_free:
     kfree(ino);
     return err;
 
 out_ro:
     ubifs_ro_mode(c, err);
     kfree(ino);
     return err;
 }
 
 /**
  * kill_orphans - remove all orphan inodes from the index.
  * @c: UBIFS file-system description object
  *
  * If recovery is required, then orphan inodes recorded during the previous
  * session (which ended with an unclean unmount) must be deleted from the index.
  * This is done by updating the TNC, but since the index is not updated until
  * the next commit, the LEBs where the orphan information is recorded are not
  * erased until the next commit.
  */
 static int kill_orphans(struct ubifs_info *c)
 {
     unsigned long long last_cmt_no = 0;
     int lnum, err = 0, outofdate = 0, last_flagged = 0;
 
     c->ohead_lnum = c->orph_first;
     c->ohead_offs = 0;
     /* Check no-orphans flag and skip this if no orphans */
     if (c->no_orphs) {
         dbg_rcvry("no orphans");
         return 0;
     }
     /*
      * Orph nodes always start at c->orph_first and are written to each
      * successive LEB in turn. Generally unused LEBs will have been unmapped
      * but may contain out of date orphan nodes if the unmap didn't go
      * through. In addition, the last orphan node written for each commit is
      * marked (top bit of orph->cmt_no is set to 1). It is possible that
      * there are orphan nodes from the next commit (i.e. the commit did not
      * complete successfully). In that case, no orphans will have been lost
      * due to the way that orphans are written, and any orphans added will
      * be valid orphans anyway and so can be deleted.
      */
     for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
         struct ubifs_scan_leb *sleb;
 
         dbg_rcvry("LEB %d", lnum);
         sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
         if (IS_ERR(sleb)) {
             if (PTR_ERR(sleb) == -EUCLEAN)
                 sleb = ubifs_recover_leb(c, lnum, 0,
                              c->sbuf, -1);
             if (IS_ERR(sleb)) {
                 err = PTR_ERR(sleb);
                 break;
             }
         }
         err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
                       &last_flagged);
         if (err || outofdate) {
             ubifs_scan_destroy(sleb);
             break;
         }
         if (sleb->endpt) {
             c->ohead_lnum = lnum;
             c->ohead_offs = sleb->endpt;
         }
         ubifs_scan_destroy(sleb);
     }
     return err;
 }
 
 /**
  * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
  * @c: UBIFS file-system description object
  * @unclean: indicates recovery from unclean unmount
  * @read_only: indicates read only mount
  *
  * This function is called when mounting to erase orphans from the previous
  * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
  * orphans are deleted.
  */
 int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
 {
     int err = 0;
 
     c->max_orphans = tot_avail_orphs(c);
 
     if (!read_only) {
         c->orph_buf = vmalloc(c->leb_size);
         if (!c->orph_buf)
             return -ENOMEM;
     }
 
     if (unclean)
         err = kill_orphans(c);
     else if (!read_only)
         err = ubifs_clear_orphans(c);
 
     return err;
 }
 
 /*
  * Everything below is related to debugging.
  */
 
 struct check_orphan {
     struct rb_node rb;
     ino_t inum;
 };
 
 struct check_info {
     unsigned long last_ino;
     unsigned long tot_inos;
     unsigned long missing;
     unsigned long long leaf_cnt;
     struct ubifs_ino_node *node;
     struct rb_root root;
 };
 
 static bool dbg_find_orphan(struct ubifs_info *c, ino_t inum)
 {
     bool found = false;
 
     spin_lock(&c->orphan_lock);
     found = !!lookup_orphan(c, inum);
     spin_unlock(&c->orphan_lock);
 
     return found;
 }
 
 static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
 {
     struct check_orphan *orphan, *o;
     struct rb_node **p, *parent = NULL;
 
     orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
     if (!orphan)
         return -ENOMEM;
     orphan->inum = inum;
 
     p = &root->rb_node;
     while (*p) {
         parent = *p;
         o = rb_entry(parent, struct check_orphan, rb);
         if (inum < o->inum)
             p = &(*p)->rb_left;
         else if (inum > o->inum)
             p = &(*p)->rb_right;
         else {
             kfree(orphan);
             return 0;
         }
     }
     rb_link_node(&orphan->rb, parent, p);
     rb_insert_color(&orphan->rb, root);
     return 0;
 }
 
 static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
 {
     struct check_orphan *o;
     struct rb_node *p;
 
     p = root->rb_node;
     while (p) {
         o = rb_entry(p, struct check_orphan, rb);
         if (inum < o->inum)
             p = p->rb_left;
         else if (inum > o->inum)
             p = p->rb_right;
         else
             return 1;
     }
     return 0;
 }
 
 static void dbg_free_check_tree(struct rb_root *root)
 {
     struct check_orphan *o, *n;
 
     rbtree_postorder_for_each_entry_safe(o, n, root, rb)
         kfree(o);
 }
 
 static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
                 void *priv)
 {
     struct check_info *ci = priv;
     ino_t inum;
     int err;
 
     inum = key_inum(c, &zbr->key);
     if (inum != ci->last_ino) {
         /* Lowest node type is the inode node, so it comes first */
         if (key_type(c, &zbr->key) != UBIFS_INO_KEY)
             ubifs_err(c, "found orphan node ino %lu, type %d",
                   (unsigned long)inum, key_type(c, &zbr->key));
         ci->last_ino = inum;
         ci->tot_inos += 1;
         err = ubifs_tnc_read_node(c, zbr, ci->node);
         if (err) {
             ubifs_err(c, "node read failed, error %d", err);
             return err;
         }
         if (ci->node->nlink == 0)
             /* Must be recorded as an orphan */
             if (!dbg_find_check_orphan(&ci->root, inum) &&
                 !dbg_find_orphan(c, inum)) {
                 ubifs_err(c, "missing orphan, ino %lu",
                       (unsigned long)inum);
                 ci->missing += 1;
             }
     }
     ci->leaf_cnt += 1;
     return 0;
 }
 
 static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
 {
     struct ubifs_scan_node *snod;
     struct ubifs_orph_node *orph;
     ino_t inum;
     int i, n, err;
 
     list_for_each_entry(snod, &sleb->nodes, list) {
         cond_resched();
         if (snod->type != UBIFS_ORPH_NODE)
             continue;
         orph = snod->node;
         n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
         for (i = 0; i < n; i++) {
             inum = le64_to_cpu(orph->inos[i]);
             err = dbg_ins_check_orphan(&ci->root, inum);
             if (err)
                 return err;
         }
     }
     return 0;
 }
 
 static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
 {
     int lnum, err = 0;
     void *buf;
 
     /* Check no-orphans flag and skip this if no orphans */
     if (c->no_orphs)
         return 0;
 
     buf = __vmalloc(c->leb_size, GFP_NOFS);
     if (!buf) {
         ubifs_err(c, "cannot allocate memory to check orphans");
         return 0;
     }
 
     for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
         struct ubifs_scan_leb *sleb;
 
         sleb = ubifs_scan(c, lnum, 0, buf, 0);
         if (IS_ERR(sleb)) {
             err = PTR_ERR(sleb);
             break;
         }
 
         err = dbg_read_orphans(ci, sleb);
         ubifs_scan_destroy(sleb);
         if (err)
             break;
     }
 
     vfree(buf);
     return err;
 }
 
 static int dbg_check_orphans(struct ubifs_info *c)
 {
     struct check_info ci;
     int err;
 
     if (!dbg_is_chk_orph(c))
         return 0;
 
     ci.last_ino = 0;
     ci.tot_inos = 0;
     ci.missing  = 0;
     ci.leaf_cnt = 0;
     ci.root = RB_ROOT;
     ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
     if (!ci.node) {
         ubifs_err(c, "out of memory");
         return -ENOMEM;
     }
 
     err = dbg_scan_orphans(c, &ci);
     if (err)
         goto out;
 
     err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
     if (err) {
         ubifs_err(c, "cannot scan TNC, error %d", err);
         goto out;
     }
 
     if (ci.missing) {
         ubifs_err(c, "%lu missing orphan(s)", ci.missing);
         err = -EINVAL;
         goto out;
     }
 
     dbg_cmt("last inode number is %lu", ci.last_ino);
     dbg_cmt("total number of inodes is %lu", ci.tot_inos);
     dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
 
 out:
     dbg_free_check_tree(&ci.root);
     kfree(ci.node);
     return err;
 }

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