fs/ubifs/orphan.c - uboot/armada - Git at Google

 /*
  * This file is part of UBIFS.
  *
  * Copyright (C) 2006-2008 Nokia Corporation.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published by
  * the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program; if not, write to the Free Software Foundation, Inc., 51
  * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  *
  * 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.
  */

 /**
  * 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;
 }

 /**
  * 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->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;
 	unsigned long long cmt_no;
 	ino_t inum;
 	int i, n, err, first = 1;

 	list_for_each_entry(snod, &sleb->nodes, list) {
 		if (snod->type != UBIFS_ORPH_NODE) {
 			ubifs_err("invalid node type %d in orphan area at "
 				  "%d:%d", snod->type, sleb->lnum, snod->offs);
 			dbg_dump_node(c, snod->node);
 			return -EINVAL;
 		}

 		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("out of order commit number %llu in "
 					  "orphan node at %d:%d",
 					  cmt_no, sleb->lnum, snod->offs);
 				dbg_dump_node(c, snod->node);
 				return -EINVAL;
 			}
 			dbg_rcvry("out of date LEB %d", sleb->lnum);
 			*outofdate = 1;
 			return 0;
 		}

 		if (first)
 			first = 0;

 		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]);
 			dbg_rcvry("deleting orphaned inode %lu",
 				  (unsigned long)inum);
 			err = ubifs_tnc_remove_ino(c, inum);
 			if (err)
 				return err;
 			err = insert_dead_orphan(c, inum);
 			if (err)
 				return err;
 		}

 		*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;
 	}

 	return 0;
 }

 /**
  * 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);
 		if (IS_ERR(sleb)) {
 			sleb = ubifs_recover_leb(c, lnum, 0, c->sbuf, 0);
 			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;
 }
	/*
	* This file is part of UBIFS.
	*
	* Copyright (C) 2006-2008 Nokia Corporation.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 as published by
	* the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program; if not, write to the Free Software Foundation, Inc., 51
	* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	*
	* 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.
	*/

	/**
	* 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;
	}

	/**
	* 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->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;
	unsigned long long cmt_no;
	ino_t inum;
	int i, n, err, first = 1;

	list_for_each_entry(snod, &sleb->nodes, list) {
	if (snod->type != UBIFS_ORPH_NODE) {
	ubifs_err("invalid node type %d in orphan area at "
	"%d:%d", snod->type, sleb->lnum, snod->offs);
	dbg_dump_node(c, snod->node);
	return -EINVAL;
	}

	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("out of order commit number %llu in "
	"orphan node at %d:%d",
	cmt_no, sleb->lnum, snod->offs);
	dbg_dump_node(c, snod->node);
	return -EINVAL;
	}
	dbg_rcvry("out of date LEB %d", sleb->lnum);
	*outofdate = 1;
	return 0;
	}

	if (first)
	first = 0;

	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]);
	dbg_rcvry("deleting orphaned inode %lu",
	(unsigned long)inum);
	err = ubifs_tnc_remove_ino(c, inum);
	if (err)
	return err;
	err = insert_dead_orphan(c, inum);
	if (err)
	return err;
	}

	*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;
	}

	return 0;
	}

	/**
	* 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);
	if (IS_ERR(sleb)) {
	sleb = ubifs_recover_leb(c, lnum, 0, c->sbuf, 0);
	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;
	}