[U-Boot] [PATCH v3] Enable journal replay for UBIFS

[Heiko Schocher]

Hello Anton,

Am 20.01.2015 15:22, schrieb Anton Habegger:
> Hello Heiko
>
> Thank you fro the review. I added atomic_long_read in ubifs.h as
> for other atomic operations.

Hmm.. I see, there are other missing "atomic" defines for UBI also ...
Ok, I tend to accept your patch, but the correct way would
be to import "include/asm-generic/atomic-long.h" from linux
and drop this definitions in ubifs.h ... Could you prepare
such a second patch?

> I hope (but I can't garantee) by this time the mail is well
> formed. If not please tell me again.

It looks good now!

> During mount_ubifs the ubifs_replay_journal was disabled. This patch
> enables it again and fix some unrecoverable UBIFS volumes.

nitpick ... Sorry, this is not a valid commit message ... please look at

http://www.denx.de/wiki/view/U-Boot/Patches

how to write a commit message. Please add comments to your patch
under a "---" line, and provide a patch history ... add also a
hint from which linux version you picked up the new file fs/ubifs/gc.c

Current version of the other MTD/UBI/UBIFS files is

1860e379875df: Linux 3.15

Could you use this as base for your patch?

Thanks!

> Signed-off-by: Anton Habegger <anton.habegger at delta-es.com>
> ---
>   fs/ubifs/Makefile |   2 +-
>   fs/ubifs/gc.c     | 987 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   fs/ubifs/replay.c |   4 -
>   fs/ubifs/super.c  |   8 +-
>   fs/ubifs/tnc.c    |   2 -
>   fs/ubifs/ubifs.h  |   1 +
>   6 files changed, 990 insertions(+), 14 deletions(-)
>   create mode 100644 fs/ubifs/gc.c

Compiling current mainline with your patch drops the follwoing
warning:


   CC      fs/ubifs/tnc.o
fs/ubifs/tnc.c: In function 'ubifs_tnc_close':
fs/ubifs/tnc.c:2861:8: warning: variable 'n' set but not used [-Wunused-but-set-variable]

Could you please fix this too? Thanks!

Beside of this nitpicks, your patch looks good.

bye,
Heiko

> diff --git a/fs/ubifs/Makefile b/fs/ubifs/Makefile
> index 8c8c6ac..5efb349 100644
> --- a/fs/ubifs/Makefile
> +++ b/fs/ubifs/Makefile
> @@ -12,4 +12,4 @@
>   obj-y := ubifs.o io.o super.o sb.o master.o lpt.o
>   obj-y += lpt_commit.o scan.o lprops.o
>   obj-y += tnc.o tnc_misc.o debug.o crc16.o budget.o
> -obj-y += log.o orphan.o recovery.o replay.o
> +obj-y += log.o orphan.o recovery.o replay.o gc.o
> diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
> new file mode 100644
> index 0000000..159ee67
> --- /dev/null
> +++ b/fs/ubifs/gc.c
> @@ -0,0 +1,987 @@
> +/*
> + * 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
> + *
> + * Authors: Adrian Hunter
> + *          Artem Bityutskiy (Битюцкий Артём)
> + */
> +
> +/*
> + * This file implements garbage collection. The procedure for garbage collection
> + * is different depending on whether a LEB as an index LEB (contains index
> + * nodes) or not. For non-index LEBs, garbage collection finds a LEB which
> + * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete
> + * nodes to the journal, at which point the garbage-collected LEB is free to be
> + * reused. For index LEBs, garbage collection marks the non-obsolete index nodes
> + * dirty in the TNC, and after the next commit, the garbage-collected LEB is
> + * to be reused. Garbage collection will cause the number of dirty index nodes
> + * to grow, however sufficient space is reserved for the index to ensure the
> + * commit will never run out of space.
> + *
> + * Notes about dead watermark. At current UBIFS implementation we assume that
> + * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
> + * and not worth garbage-collecting. The dead watermark is one min. I/O unit
> + * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
> + * Garbage Collector has to synchronize the GC head's write buffer before
> + * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
> + * actually reclaim even very small pieces of dirty space by garbage collecting
> + * enough dirty LEBs, but we do not bother doing this at this implementation.
> + *
> + * Notes about dark watermark. The results of GC work depends on how big are
> + * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
> + * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
> + * have to waste large pieces of free space at the end of LEB B, because nodes
> + * from LEB A would not fit. And the worst situation is when all nodes are of
> + * maximum size. So dark watermark is the amount of free + dirty space in LEB
> + * which are guaranteed to be reclaimable. If LEB has less space, the GC might
> + * be unable to reclaim it. So, LEBs with free + dirty greater than dark
> + * watermark are "good" LEBs from GC's point of few. The other LEBs are not so
> + * good, and GC takes extra care when moving them.
> + */
> +#ifndef __UBOOT__
> +#include <linux/slab.h>
> +#include <linux/pagemap.h>
> +#include <linux/list_sort.h>
> +#endif
> +#include "ubifs.h"
> +
> +#ifndef __UBOOT__
> +/*
> + * GC may need to move more than one LEB to make progress. The below constants
> + * define "soft" and "hard" limits on the number of LEBs the garbage collector
> + * may move.
> + */
> +#define SOFT_LEBS_LIMIT 4
> +#define HARD_LEBS_LIMIT 32
> +
> +/**
> + * switch_gc_head - switch the garbage collection journal head.
> + * @c: UBIFS file-system description object
> + * @buf: buffer to write
> + * @len: length of the buffer to write
> + * @lnum: LEB number written is returned here
> + * @offs: offset written is returned here
> + *
> + * This function switch the GC head to the next LEB which is reserved in
> + * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
> + * and other negative error code in case of failures.
> + */
> +static int switch_gc_head(struct ubifs_info *c)
> +{
> +	int err, gc_lnum = c->gc_lnum;
> +	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
> +
> +	ubifs_assert(gc_lnum != -1);
> +	dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
> +	       wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum,
> +	       c->leb_size - wbuf->offs - wbuf->used);
> +
> +	err = ubifs_wbuf_sync_nolock(wbuf);
> +	if (err)
> +		return err;
> +
> +	/*
> +	 * The GC write-buffer was synchronized, we may safely unmap
> +	 * 'c->gc_lnum'.
> +	 */
> +	err = ubifs_leb_unmap(c, gc_lnum);
> +	if (err)
> +		return err;
> +
> +	err = ubifs_wbuf_sync_nolock(wbuf);
> +	if (err)
> +		return err;
> +
> +	err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
> +	if (err)
> +		return err;
> +
> +	c->gc_lnum = -1;
> +	err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0);
> +	return err;
> +}
> +
> +/**
> + * data_nodes_cmp - compare 2 data nodes.
> + * @priv: UBIFS file-system description object
> + * @a: first data node
> + * @a: second data node
> + *
> + * This function compares data nodes @a and @b. Returns %1 if @a has greater
> + * inode or block number, and %-1 otherwise.
> + */
> +static int data_nodes_cmp(void *priv, struct list_head *a, struct list_head *b)
> +{
> +	ino_t inuma, inumb;
> +	struct ubifs_info *c = priv;
> +	struct ubifs_scan_node *sa, *sb;
> +
> +	cond_resched();
> +	if (a == b)
> +		return 0;
> +
> +	sa = list_entry(a, struct ubifs_scan_node, list);
> +	sb = list_entry(b, struct ubifs_scan_node, list);
> +
> +	ubifs_assert(key_type(c, &sa->key) == UBIFS_DATA_KEY);
> +	ubifs_assert(key_type(c, &sb->key) == UBIFS_DATA_KEY);
> +	ubifs_assert(sa->type == UBIFS_DATA_NODE);
> +	ubifs_assert(sb->type == UBIFS_DATA_NODE);
> +
> +	inuma = key_inum(c, &sa->key);
> +	inumb = key_inum(c, &sb->key);
> +
> +	if (inuma == inumb) {
> +		unsigned int blka = key_block(c, &sa->key);
> +		unsigned int blkb = key_block(c, &sb->key);
> +
> +		if (blka <= blkb)
> +			return -1;
> +	} else if (inuma <= inumb)
> +		return -1;
> +
> +	return 1;
> +}
> +
> +/*
> + * nondata_nodes_cmp - compare 2 non-data nodes.
> + * @priv: UBIFS file-system description object
> + * @a: first node
> + * @a: second node
> + *
> + * This function compares nodes @a and @b. It makes sure that inode nodes go
> + * first and sorted by length in descending order. Directory entry nodes go
> + * after inode nodes and are sorted in ascending hash valuer order.
> + */
> +static int nondata_nodes_cmp(void *priv, struct list_head *a,
> +			     struct list_head *b)
> +{
> +	ino_t inuma, inumb;
> +	struct ubifs_info *c = priv;
> +	struct ubifs_scan_node *sa, *sb;
> +
> +	cond_resched();
> +	if (a == b)
> +		return 0;
> +
> +	sa = list_entry(a, struct ubifs_scan_node, list);
> +	sb = list_entry(b, struct ubifs_scan_node, list);
> +
> +	ubifs_assert(key_type(c, &sa->key) != UBIFS_DATA_KEY &&
> +		     key_type(c, &sb->key) != UBIFS_DATA_KEY);
> +	ubifs_assert(sa->type != UBIFS_DATA_NODE &&
> +		     sb->type != UBIFS_DATA_NODE);
> +
> +	/* Inodes go before directory entries */
> +	if (sa->type == UBIFS_INO_NODE) {
> +		if (sb->type == UBIFS_INO_NODE)
> +			return sb->len - sa->len;
> +		return -1;
> +	}
> +	if (sb->type == UBIFS_INO_NODE)
> +		return 1;
> +
> +	ubifs_assert(key_type(c, &sa->key) == UBIFS_DENT_KEY ||
> +		     key_type(c, &sa->key) == UBIFS_XENT_KEY);
> +	ubifs_assert(key_type(c, &sb->key) == UBIFS_DENT_KEY ||
> +		     key_type(c, &sb->key) == UBIFS_XENT_KEY);
> +	ubifs_assert(sa->type == UBIFS_DENT_NODE ||
> +		     sa->type == UBIFS_XENT_NODE);
> +	ubifs_assert(sb->type == UBIFS_DENT_NODE ||
> +		     sb->type == UBIFS_XENT_NODE);
> +
> +	inuma = key_inum(c, &sa->key);
> +	inumb = key_inum(c, &sb->key);
> +
> +	if (inuma == inumb) {
> +		uint32_t hasha = key_hash(c, &sa->key);
> +		uint32_t hashb = key_hash(c, &sb->key);
> +
> +		if (hasha <= hashb)
> +			return -1;
> +	} else if (inuma <= inumb)
> +		return -1;
> +
> +	return 1;
> +}
> +
> +/**
> + * sort_nodes - sort nodes for GC.
> + * @c: UBIFS file-system description object
> + * @sleb: describes nodes to sort and contains the result on exit
> + * @nondata: contains non-data nodes on exit
> + * @min: minimum node size is returned here
> + *
> + * This function sorts the list of inodes to garbage collect. First of all, it
> + * kills obsolete nodes and separates data and non-data nodes to the
> + * @sleb->nodes and @nondata lists correspondingly.
> + *
> + * Data nodes are then sorted in block number order - this is important for
> + * bulk-read; data nodes with lower inode number go before data nodes with
> + * higher inode number, and data nodes with lower block number go before data
> + * nodes with higher block number;
> + *
> + * Non-data nodes are sorted as follows.
> + *   o First go inode nodes - they are sorted in descending length order.
> + *   o Then go directory entry nodes - they are sorted in hash order, which
> + *     should supposedly optimize 'readdir()'. Direntry nodes with lower parent
> + *     inode number go before direntry nodes with higher parent inode number,
> + *     and direntry nodes with lower name hash values go before direntry nodes
> + *     with higher name hash values.
> + *
> + * This function returns zero in case of success and a negative error code in
> + * case of failure.
> + */
> +static int sort_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
> +		      struct list_head *nondata, int *min)
> +{
> +	int err;
> +	struct ubifs_scan_node *snod, *tmp;
> +
> +	*min = INT_MAX;
> +
> +	/* Separate data nodes and non-data nodes */
> +	list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
> +		ubifs_assert(snod->type == UBIFS_INO_NODE  ||
> +			     snod->type == UBIFS_DATA_NODE ||
> +			     snod->type == UBIFS_DENT_NODE ||
> +			     snod->type == UBIFS_XENT_NODE ||
> +			     snod->type == UBIFS_TRUN_NODE);
> +
> +		if (snod->type != UBIFS_INO_NODE  &&
> +		    snod->type != UBIFS_DATA_NODE &&
> +		    snod->type != UBIFS_DENT_NODE &&
> +		    snod->type != UBIFS_XENT_NODE) {
> +			/* Probably truncation node, zap it */
> +			list_del(&snod->list);
> +			kfree(snod);
> +			continue;
> +		}
> +
> +		ubifs_assert(key_type(c, &snod->key) == UBIFS_DATA_KEY ||
> +			     key_type(c, &snod->key) == UBIFS_INO_KEY  ||
> +			     key_type(c, &snod->key) == UBIFS_DENT_KEY ||
> +			     key_type(c, &snod->key) == UBIFS_XENT_KEY);
> +
> +		err = ubifs_tnc_has_node(c, &snod->key, 0, sleb->lnum,
> +					 snod->offs, 0);
> +		if (err < 0)
> +			return err;
> +
> +		if (!err) {
> +			/* The node is obsolete, remove it from the list */
> +			list_del(&snod->list);
> +			kfree(snod);
> +			continue;
> +		}
> +
> +		if (snod->len < *min)
> +			*min = snod->len;
> +
> +		if (key_type(c, &snod->key) != UBIFS_DATA_KEY)
> +			list_move_tail(&snod->list, nondata);
> +	}
> +
> +	/* Sort data and non-data nodes */
> +	list_sort(c, &sleb->nodes, &data_nodes_cmp);
> +	list_sort(c, nondata, &nondata_nodes_cmp);
> +
> +	err = dbg_check_data_nodes_order(c, &sleb->nodes);
> +	if (err)
> +		return err;
> +	err = dbg_check_nondata_nodes_order(c, nondata);
> +	if (err)
> +		return err;
> +	return 0;
> +}
> +
> +/**
> + * move_node - move a node.
> + * @c: UBIFS file-system description object
> + * @sleb: describes the LEB to move nodes from
> + * @snod: the mode to move
> + * @wbuf: write-buffer to move node to
> + *
> + * This function moves node @snod to @wbuf, changes TNC correspondingly, and
> + * destroys @snod. Returns zero in case of success and a negative error code in
> + * case of failure.
> + */
> +static int move_node(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
> +		     struct ubifs_scan_node *snod, struct ubifs_wbuf *wbuf)
> +{
> +	int err, new_lnum = wbuf->lnum, new_offs = wbuf->offs + wbuf->used;
> +
> +	cond_resched();
> +	err = ubifs_wbuf_write_nolock(wbuf, snod->node, snod->len);
> +	if (err)
> +		return err;
> +
> +	err = ubifs_tnc_replace(c, &snod->key, sleb->lnum,
> +				snod->offs, new_lnum, new_offs,
> +				snod->len);
> +	list_del(&snod->list);
> +	kfree(snod);
> +	return err;
> +}
> +
> +/**
> + * move_nodes - move nodes.
> + * @c: UBIFS file-system description object
> + * @sleb: describes the LEB to move nodes from
> + *
> + * This function moves valid nodes from data LEB described by @sleb to the GC
> + * journal head. This function returns zero in case of success, %-EAGAIN if
> + * commit is required, and other negative error codes in case of other
> + * failures.
> + */
> +static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
> +{
> +	int err, min;
> +	LIST_HEAD(nondata);
> +	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
> +
> +	if (wbuf->lnum == -1) {
> +		/*
> +		 * The GC journal head is not set, because it is the first GC
> +		 * invocation since mount.
> +		 */
> +		err = switch_gc_head(c);
> +		if (err)
> +			return err;
> +	}
> +
> +	err = sort_nodes(c, sleb, &nondata, &min);
> +	if (err)
> +		goto out;
> +
> +	/* Write nodes to their new location. Use the first-fit strategy */
> +	while (1) {
> +		int avail;
> +		struct ubifs_scan_node *snod, *tmp;
> +
> +		/* Move data nodes */
> +		list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
> +			avail = c->leb_size - wbuf->offs - wbuf->used;
> +			if  (snod->len > avail)
> +				/*
> +				 * Do not skip data nodes in order to optimize
> +				 * bulk-read.
> +				 */
> +				break;
> +
> +			err = move_node(c, sleb, snod, wbuf);
> +			if (err)
> +				goto out;
> +		}
> +
> +		/* Move non-data nodes */
> +		list_for_each_entry_safe(snod, tmp, &nondata, list) {
> +			avail = c->leb_size - wbuf->offs - wbuf->used;
> +			if (avail < min)
> +				break;
> +
> +			if  (snod->len > avail) {
> +				/*
> +				 * Keep going only if this is an inode with
> +				 * some data. Otherwise stop and switch the GC
> +				 * head. IOW, we assume that data-less inode
> +				 * nodes and direntry nodes are roughly of the
> +				 * same size.
> +				 */
> +				if (key_type(c, &snod->key) == UBIFS_DENT_KEY ||
> +				    snod->len == UBIFS_INO_NODE_SZ)
> +					break;
> +				continue;
> +			}
> +
> +			err = move_node(c, sleb, snod, wbuf);
> +			if (err)
> +				goto out;
> +		}
> +
> +		if (list_empty(&sleb->nodes) && list_empty(&nondata))
> +			break;
> +
> +		/*
> +		 * Waste the rest of the space in the LEB and switch to the
> +		 * next LEB.
> +		 */
> +		err = switch_gc_head(c);
> +		if (err)
> +			goto out;
> +	}
> +
> +	return 0;
> +
> +out:
> +	list_splice_tail(&nondata, &sleb->nodes);
> +	return err;
> +}
> +
> +/**
> + * gc_sync_wbufs - sync write-buffers for GC.
> + * @c: UBIFS file-system description object
> + *
> + * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
> + * be in a write-buffer instead. That is, a node could be written to a
> + * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
> + * erased before the write-buffer is sync'd and then there is an unclean
> + * unmount, then an existing node is lost. To avoid this, we sync all
> + * write-buffers.
> + *
> + * This function returns %0 on success or a negative error code on failure.
> + */
> +static int gc_sync_wbufs(struct ubifs_info *c)
> +{
> +	int err, i;
> +
> +	for (i = 0; i < c->jhead_cnt; i++) {
> +		if (i == GCHD)
> +			continue;
> +		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
> +		if (err)
> +			return err;
> +	}
> +	return 0;
> +}
> +
> +/**
> + * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
> + * @c: UBIFS file-system description object
> + * @lp: describes the LEB to garbage collect
> + *
> + * This function garbage-collects an LEB and returns one of the @LEB_FREED,
> + * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
> + * required, and other negative error codes in case of failures.
> + */
> +int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
> +{
> +	struct ubifs_scan_leb *sleb;
> +	struct ubifs_scan_node *snod;
> +	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
> +	int err = 0, lnum = lp->lnum;
> +
> +	ubifs_assert(c->gc_lnum != -1 || wbuf->offs + wbuf->used == 0 ||
> +		     c->need_recovery);
> +	ubifs_assert(c->gc_lnum != lnum);
> +	ubifs_assert(wbuf->lnum != lnum);
> +
> +	if (lp->free + lp->dirty == c->leb_size) {
> +		/* Special case - a free LEB  */
> +		dbg_gc("LEB %d is free, return it", lp->lnum);
> +		ubifs_assert(!(lp->flags & LPROPS_INDEX));
> +
> +		if (lp->free != c->leb_size) {
> +			/*
> +			 * Write buffers must be sync'd before unmapping
> +			 * freeable LEBs, because one of them may contain data
> +			 * which obsoletes something in 'lp->pnum'.
> +			 */
> +			err = gc_sync_wbufs(c);
> +			if (err)
> +				return err;
> +			err = ubifs_change_one_lp(c, lp->lnum, c->leb_size,
> +						  0, 0, 0, 0);
> +			if (err)
> +				return err;
> +		}
> +		err = ubifs_leb_unmap(c, lp->lnum);
> +		if (err)
> +			return err;
> +
> +		if (c->gc_lnum == -1) {
> +			c->gc_lnum = lnum;
> +			return LEB_RETAINED;
> +		}
> +
> +		return LEB_FREED;
> +	}
> +
> +	/*
> +	 * We scan the entire LEB even though we only really need to scan up to
> +	 * (c->leb_size - lp->free).
> +	 */
> +	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
> +	if (IS_ERR(sleb))
> +		return PTR_ERR(sleb);
> +
> +	ubifs_assert(!list_empty(&sleb->nodes));
> +	snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
> +
> +	if (snod->type == UBIFS_IDX_NODE) {
> +		struct ubifs_gced_idx_leb *idx_gc;
> +
> +		dbg_gc("indexing LEB %d (free %d, dirty %d)",
> +		       lnum, lp->free, lp->dirty);
> +		list_for_each_entry(snod, &sleb->nodes, list) {
> +			struct ubifs_idx_node *idx = snod->node;
> +			int level = le16_to_cpu(idx->level);
> +
> +			ubifs_assert(snod->type == UBIFS_IDX_NODE);
> +			key_read(c, ubifs_idx_key(c, idx), &snod->key);
> +			err = ubifs_dirty_idx_node(c, &snod->key, level, lnum,
> +						   snod->offs);
> +			if (err)
> +				goto out;
> +		}
> +
> +		idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
> +		if (!idx_gc) {
> +			err = -ENOMEM;
> +			goto out;
> +		}
> +
> +		idx_gc->lnum = lnum;
> +		idx_gc->unmap = 0;
> +		list_add(&idx_gc->list, &c->idx_gc);
> +
> +		/*
> +		 * Don't release the LEB until after the next commit, because
> +		 * it may contain data which is needed for recovery. So
> +		 * although we freed this LEB, it will become usable only after
> +		 * the commit.
> +		 */
> +		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0,
> +					  LPROPS_INDEX, 1);
> +		if (err)
> +			goto out;
> +		err = LEB_FREED_IDX;
> +	} else {
> +		dbg_gc("data LEB %d (free %d, dirty %d)",
> +		       lnum, lp->free, lp->dirty);
> +
> +		err = move_nodes(c, sleb);
> +		if (err)
> +			goto out_inc_seq;
> +
> +		err = gc_sync_wbufs(c);
> +		if (err)
> +			goto out_inc_seq;
> +
> +		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
> +		if (err)
> +			goto out_inc_seq;
> +
> +		/* Allow for races with TNC */
> +		c->gced_lnum = lnum;
> +		smp_wmb();
> +		c->gc_seq += 1;
> +		smp_wmb();
> +
> +		if (c->gc_lnum == -1) {
> +			c->gc_lnum = lnum;
> +			err = LEB_RETAINED;
> +		} else {
> +			err = ubifs_wbuf_sync_nolock(wbuf);
> +			if (err)
> +				goto out;
> +
> +			err = ubifs_leb_unmap(c, lnum);
> +			if (err)
> +				goto out;
> +
> +			err = LEB_FREED;
> +		}
> +	}
> +
> +out:
> +	ubifs_scan_destroy(sleb);
> +	return err;
> +
> +out_inc_seq:
> +	/* We may have moved at least some nodes so allow for races with TNC */
> +	c->gced_lnum = lnum;
> +	smp_wmb();
> +	c->gc_seq += 1;
> +	smp_wmb();
> +	goto out;
> +}
> +
> +/**
> + * ubifs_garbage_collect - UBIFS garbage collector.
> + * @c: UBIFS file-system description object
> + * @anyway: do GC even if there are free LEBs
> + *
> + * This function does out-of-place garbage collection. The return codes are:
> + *   o positive LEB number if the LEB has been freed and may be used;
> + *   o %-EAGAIN if the caller has to run commit;
> + *   o %-ENOSPC if GC failed to make any progress;
> + *   o other negative error codes in case of other errors.
> + *
> + * Garbage collector writes data to the journal when GC'ing data LEBs, and just
> + * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
> + * commit may be required. But commit cannot be run from inside GC, because the
> + * caller might be holding the commit lock, so %-EAGAIN is returned instead;
> + * And this error code means that the caller has to run commit, and re-run GC
> + * if there is still no free space.
> + *
> + * There are many reasons why this function may return %-EAGAIN:
> + * o the log is full and there is no space to write an LEB reference for
> + *   @c->gc_lnum;
> + * o the journal is too large and exceeds size limitations;
> + * o GC moved indexing LEBs, but they can be used only after the commit;
> + * o the shrinker fails to find clean znodes to free and requests the commit;
> + * o etc.
> + *
> + * Note, if the file-system is close to be full, this function may return
> + * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
> + * the function. E.g., this happens if the limits on the journal size are too
> + * tough and GC writes too much to the journal before an LEB is freed. This
> + * might also mean that the journal is too large, and the TNC becomes to big,
> + * so that the shrinker is constantly called, finds not clean znodes to free,
> + * and requests commit. Well, this may also happen if the journal is all right,
> + * but another kernel process consumes too much memory. Anyway, infinite
> + * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
> + */
> +int ubifs_garbage_collect(struct ubifs_info *c, int anyway)
> +{
> +	int i, err, ret, min_space = c->dead_wm;
> +	struct ubifs_lprops lp;
> +	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
> +
> +	ubifs_assert_cmt_locked(c);
> +	ubifs_assert(!c->ro_media && !c->ro_mount);
> +
> +	if (ubifs_gc_should_commit(c))
> +		return -EAGAIN;
> +
> +	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
> +
> +	if (c->ro_error) {
> +		ret = -EROFS;
> +		goto out_unlock;
> +	}
> +
> +	/* We expect the write-buffer to be empty on entry */
> +	ubifs_assert(!wbuf->used);
> +
> +	for (i = 0; ; i++) {
> +		int space_before, space_after;
> +
> +		cond_resched();
> +
> +		/* Give the commit an opportunity to run */
> +		if (ubifs_gc_should_commit(c)) {
> +			ret = -EAGAIN;
> +			break;
> +		}
> +
> +		if (i > SOFT_LEBS_LIMIT && !list_empty(&c->idx_gc)) {
> +			/*
> +			 * We've done enough iterations. Indexing LEBs were
> +			 * moved and will be available after the commit.
> +			 */
> +			dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
> +			ubifs_commit_required(c);
> +			ret = -EAGAIN;
> +			break;
> +		}
> +
> +		if (i > HARD_LEBS_LIMIT) {
> +			/*
> +			 * We've moved too many LEBs and have not made
> +			 * progress, give up.
> +			 */
> +			dbg_gc("hard limit, -ENOSPC");
> +			ret = -ENOSPC;
> +			break;
> +		}
> +
> +		/*
> +		 * Empty and freeable LEBs can turn up while we waited for
> +		 * the wbuf lock, or while we have been running GC. In that
> +		 * case, we should just return one of those instead of
> +		 * continuing to GC dirty LEBs. Hence we request
> +		 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
> +		 */
> +		ret = ubifs_find_dirty_leb(c, &lp, min_space, anyway ? 0 : 1);
> +		if (ret) {
> +			if (ret == -ENOSPC)
> +				dbg_gc("no more dirty LEBs");
> +			break;
> +		}
> +
> +		dbg_gc("found LEB %d: free %d, dirty %d, sum %d (min. space %d)",
> +		       lp.lnum, lp.free, lp.dirty, lp.free + lp.dirty,
> +		       min_space);
> +
> +		space_before = c->leb_size - wbuf->offs - wbuf->used;
> +		if (wbuf->lnum == -1)
> +			space_before = 0;
> +
> +		ret = ubifs_garbage_collect_leb(c, &lp);
> +		if (ret < 0) {
> +			if (ret == -EAGAIN) {
> +				/*
> +				 * This is not error, so we have to return the
> +				 * LEB to lprops. But if 'ubifs_return_leb()'
> +				 * fails, its failure code is propagated to the
> +				 * caller instead of the original '-EAGAIN'.
> +				 */
> +				err = ubifs_return_leb(c, lp.lnum);
> +				if (err)
> +					ret = err;
> +				break;
> +			}
> +			goto out;
> +		}
> +
> +		if (ret == LEB_FREED) {
> +			/* An LEB has been freed and is ready for use */
> +			dbg_gc("LEB %d freed, return", lp.lnum);
> +			ret = lp.lnum;
> +			break;
> +		}
> +
> +		if (ret == LEB_FREED_IDX) {
> +			/*
> +			 * This was an indexing LEB and it cannot be
> +			 * immediately used. And instead of requesting the
> +			 * commit straight away, we try to garbage collect some
> +			 * more.
> +			 */
> +			dbg_gc("indexing LEB %d freed, continue", lp.lnum);
> +			continue;
> +		}
> +
> +		ubifs_assert(ret == LEB_RETAINED);
> +		space_after = c->leb_size - wbuf->offs - wbuf->used;
> +		dbg_gc("LEB %d retained, freed %d bytes", lp.lnum,
> +		       space_after - space_before);
> +
> +		if (space_after > space_before) {
> +			/* GC makes progress, keep working */
> +			min_space >>= 1;
> +			if (min_space < c->dead_wm)
> +				min_space = c->dead_wm;
> +			continue;
> +		}
> +
> +		dbg_gc("did not make progress");
> +
> +		/*
> +		 * GC moved an LEB bud have not done any progress. This means
> +		 * that the previous GC head LEB contained too few free space
> +		 * and the LEB which was GC'ed contained only large nodes which
> +		 * did not fit that space.
> +		 *
> +		 * We can do 2 things:
> +		 * 1. pick another LEB in a hope it'll contain a small node
> +		 *    which will fit the space we have at the end of current GC
> +		 *    head LEB, but there is no guarantee, so we try this out
> +		 *    unless we have already been working for too long;
> +		 * 2. request an LEB with more dirty space, which will force
> +		 *    'ubifs_find_dirty_leb()' to start scanning the lprops
> +		 *    table, instead of just picking one from the heap
> +		 *    (previously it already picked the dirtiest LEB).
> +		 */
> +		if (i < SOFT_LEBS_LIMIT) {
> +			dbg_gc("try again");
> +			continue;
> +		}
> +
> +		min_space <<= 1;
> +		if (min_space > c->dark_wm)
> +			min_space = c->dark_wm;
> +		dbg_gc("set min. space to %d", min_space);
> +	}
> +
> +	if (ret == -ENOSPC && !list_empty(&c->idx_gc)) {
> +		dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
> +		ubifs_commit_required(c);
> +		ret = -EAGAIN;
> +	}
> +
> +	err = ubifs_wbuf_sync_nolock(wbuf);
> +	if (!err)
> +		err = ubifs_leb_unmap(c, c->gc_lnum);
> +	if (err) {
> +		ret = err;
> +		goto out;
> +	}
> +out_unlock:
> +	mutex_unlock(&wbuf->io_mutex);
> +	return ret;
> +
> +out:
> +	ubifs_assert(ret < 0);
> +	ubifs_assert(ret != -ENOSPC && ret != -EAGAIN);
> +	ubifs_wbuf_sync_nolock(wbuf);
> +	ubifs_ro_mode(c, ret);
> +	mutex_unlock(&wbuf->io_mutex);
> +	ubifs_return_leb(c, lp.lnum);
> +	return ret;
> +}
> +
> +/**
> + * ubifs_gc_start_commit - garbage collection at start of commit.
> + * @c: UBIFS file-system description object
> + *
> + * If a LEB has only dirty and free space, then we may safely unmap it and make
> + * it free.  Note, we cannot do this with indexing LEBs because dirty space may
> + * correspond index nodes that are required for recovery.  In that case, the
> + * LEB cannot be unmapped until after the next commit.
> + *
> + * This function returns %0 upon success and a negative error code upon failure.
> + */
> +int ubifs_gc_start_commit(struct ubifs_info *c)
> +{
> +	struct ubifs_gced_idx_leb *idx_gc;
> +	const struct ubifs_lprops *lp;
> +	int err = 0, flags;
> +
> +	ubifs_get_lprops(c);
> +
> +	/*
> +	 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
> +	 * wbufs are sync'd before this, which is done in 'do_commit()'.
> +	 */
> +	while (1) {
> +		lp = ubifs_fast_find_freeable(c);
> +		if (IS_ERR(lp)) {
> +			err = PTR_ERR(lp);
> +			goto out;
> +		}
> +		if (!lp)
> +			break;
> +		ubifs_assert(!(lp->flags & LPROPS_TAKEN));
> +		ubifs_assert(!(lp->flags & LPROPS_INDEX));
> +		err = ubifs_leb_unmap(c, lp->lnum);
> +		if (err)
> +			goto out;
> +		lp = ubifs_change_lp(c, lp, c->leb_size, 0, lp->flags, 0);
> +		if (IS_ERR(lp)) {
> +			err = PTR_ERR(lp);
> +			goto out;
> +		}
> +		ubifs_assert(!(lp->flags & LPROPS_TAKEN));
> +		ubifs_assert(!(lp->flags & LPROPS_INDEX));
> +	}
> +
> +	/* Mark GC'd index LEBs OK to unmap after this commit finishes */
> +	list_for_each_entry(idx_gc, &c->idx_gc, list)
> +		idx_gc->unmap = 1;
> +
> +	/* Record index freeable LEBs for unmapping after commit */
> +	while (1) {
> +		lp = ubifs_fast_find_frdi_idx(c);
> +		if (IS_ERR(lp)) {
> +			err = PTR_ERR(lp);
> +			goto out;
> +		}
> +		if (!lp)
> +			break;
> +		idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
> +		if (!idx_gc) {
> +			err = -ENOMEM;
> +			goto out;
> +		}
> +		ubifs_assert(!(lp->flags & LPROPS_TAKEN));
> +		ubifs_assert(lp->flags & LPROPS_INDEX);
> +		/* Don't release the LEB until after the next commit */
> +		flags = (lp->flags | LPROPS_TAKEN) ^ LPROPS_INDEX;
> +		lp = ubifs_change_lp(c, lp, c->leb_size, 0, flags, 1);
> +		if (IS_ERR(lp)) {
> +			err = PTR_ERR(lp);
> +			kfree(idx_gc);
> +			goto out;
> +		}
> +		ubifs_assert(lp->flags & LPROPS_TAKEN);
> +		ubifs_assert(!(lp->flags & LPROPS_INDEX));
> +		idx_gc->lnum = lp->lnum;
> +		idx_gc->unmap = 1;
> +		list_add(&idx_gc->list, &c->idx_gc);
> +	}
> +out:
> +	ubifs_release_lprops(c);
> +	return err;
> +}
> +
> +/**
> + * ubifs_gc_end_commit - garbage collection at end of commit.
> + * @c: UBIFS file-system description object
> + *
> + * This function completes out-of-place garbage collection of index LEBs.
> + */
> +int ubifs_gc_end_commit(struct ubifs_info *c)
> +{
> +	struct ubifs_gced_idx_leb *idx_gc, *tmp;
> +	struct ubifs_wbuf *wbuf;
> +	int err = 0;
> +
> +	wbuf = &c->jheads[GCHD].wbuf;
> +	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
> +	list_for_each_entry_safe(idx_gc, tmp, &c->idx_gc, list)
> +		if (idx_gc->unmap) {
> +			dbg_gc("LEB %d", idx_gc->lnum);
> +			err = ubifs_leb_unmap(c, idx_gc->lnum);
> +			if (err)
> +				goto out;
> +			err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
> +					  LPROPS_NC, 0, LPROPS_TAKEN, -1);
> +			if (err)
> +				goto out;
> +			list_del(&idx_gc->list);
> +			kfree(idx_gc);
> +		}
> +out:
> +	mutex_unlock(&wbuf->io_mutex);
> +	return err;
> +}
> +#endif
> +/**
> + * ubifs_destroy_idx_gc - destroy idx_gc list.
> + * @c: UBIFS file-system description object
> + *
> + * This function destroys the @c->idx_gc list. It is called when unmounting
> + * so locks are not needed. Returns zero in case of success and a negative
> + * error code in case of failure.
> + */
> +void ubifs_destroy_idx_gc(struct ubifs_info *c)
> +{
> +	while (!list_empty(&c->idx_gc)) {
> +		struct ubifs_gced_idx_leb *idx_gc;
> +
> +		idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
> +				    list);
> +		c->idx_gc_cnt -= 1;
> +		list_del(&idx_gc->list);
> +		kfree(idx_gc);
> +	}
> +}
> +#ifndef __UBOOT__
> +/**
> + * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
> + * @c: UBIFS file-system description object
> + *
> + * Called during start commit so locks are not needed.
> + */
> +int ubifs_get_idx_gc_leb(struct ubifs_info *c)
> +{
> +	struct ubifs_gced_idx_leb *idx_gc;
> +	int lnum;
> +
> +	if (list_empty(&c->idx_gc))
> +		return -ENOSPC;
> +	idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, list);
> +	lnum = idx_gc->lnum;
> +	/* c->idx_gc_cnt is updated by the caller when lprops are updated */
> +	list_del(&idx_gc->list);
> +	kfree(idx_gc);
> +	return lnum;
> +}
> +#endif
> diff --git a/fs/ubifs/replay.c b/fs/ubifs/replay.c
> index 7268b37..1064cb2 100644
> --- a/fs/ubifs/replay.c
> +++ b/fs/ubifs/replay.c
> @@ -78,7 +78,6 @@ struct bud_entry {
>   	int dirty;
>   };
>
> -#ifndef __UBOOT__
>   /**
>    * set_bud_lprops - set free and dirty space used by a bud.
>    * @c: UBIFS file-system description object
> @@ -432,7 +431,6 @@ static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
>   	list_add_tail(&r->list, &c->replay_list);
>   	return 0;
>   }
> -#endif
>
>   /**
>    * ubifs_validate_entry - validate directory or extended attribute entry node.
> @@ -466,7 +464,6 @@ int ubifs_validate_entry(struct ubifs_info *c,
>   	return 0;
>   }
>
> -#ifndef __UBOOT__
>   /**
>    * is_last_bud - check if the bud is the last in the journal head.
>    * @c: UBIFS file-system description object
> @@ -1063,4 +1060,3 @@ out:
>   	c->replaying = 0;
>   	return err;
>   }
> -#endif
> diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
> index 01d449a..10f8fff 100644
> --- a/fs/ubifs/super.c
> +++ b/fs/ubifs/super.c
> @@ -1049,7 +1049,6 @@ static void free_orphans(struct ubifs_info *c)
>   	c->orph_buf = NULL;
>   }
>
> -#ifndef __UBOOT__
>   /**
>    * free_buds - free per-bud objects.
>    * @c: UBIFS file-system description object
> @@ -1061,7 +1060,6 @@ static void free_buds(struct ubifs_info *c)
>   	rbtree_postorder_for_each_entry_safe(bud, n, &c->buds, rb)
>   		kfree(bud);
>   }
> -#endif
>
>   /**
>    * check_volume_empty - check if the UBI volume is empty.
> @@ -1242,6 +1240,7 @@ static int ubifs_parse_options(struct ubifs_info *c, char *options,
>
>   	return 0;
>   }
> +#endif
>
>   /**
>    * destroy_journal - destroy journal data structures.
> @@ -1272,7 +1271,6 @@ static void destroy_journal(struct ubifs_info *c)
>   	ubifs_tnc_close(c);
>   	free_buds(c);
>   }
> -#endif
>
>   /**
>    * bu_init - initialize bulk-read information.
> @@ -1502,11 +1500,9 @@ static int mount_ubifs(struct ubifs_info *c)
>   	if (err)
>   		goto out_lpt;
>
> -#ifndef __UBOOT__
>   	err = ubifs_replay_journal(c);
>   	if (err)
>   		goto out_journal;
> -#endif
>
>   	/* Calculate 'min_idx_lebs' after journal replay */
>   	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
> @@ -1678,10 +1674,8 @@ out_infos:
>   	spin_unlock(&ubifs_infos_lock);
>   out_orphans:
>   	free_orphans(c);
> -#ifndef __UBOOT__
>   out_journal:
>   	destroy_journal(c);
> -#endif
>   out_lpt:
>   	ubifs_lpt_free(c, 0);
>   out_master:
> diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
> index 95cae54..e20cedd 100644
> --- a/fs/ubifs/tnc.c
> +++ b/fs/ubifs/tnc.c
> @@ -2827,7 +2827,6 @@ out_unlock:
>   	return ERR_PTR(err);
>   }
>
> -#ifndef __UBOOT__
>   /**
>    * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
>    * @c: UBIFS file-system description object
> @@ -2869,7 +2868,6 @@ void ubifs_tnc_close(struct ubifs_info *c)
>   	kfree(c->ilebs);
>   	destroy_old_idx(c);
>   }
> -#endif
>
>   /**
>    * left_znode - get the znode to the left.
> diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
> index c120261..1be0864 100644
> --- a/fs/ubifs/ubifs.h
> +++ b/fs/ubifs/ubifs.h
> @@ -70,6 +70,7 @@ void iput(struct inode *inode);
>   #define atomic_long_inc(a)
>   #define atomic_long_dec(a)
>   #define	atomic_long_sub(a, b)
> +#define	atomic_long_read(a) *(a)
>
>   typedef unsigned long atomic_long_t;
>
>

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany