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-rw-r--r--fs/ubifs/gc.c976
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diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c
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-/*
- * This file is part of UBIFS.
- *
- * Copyright (C) 2006-2008 Nokia Corporation.
- *
- * SPDX-License-Identifier: GPL-2.0
- *
- * 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 __BAREBOX__
-#include <linux/slab.h>
-#include <linux/pagemap.h>
-#include <linux/list_sort.h>
-#endif
-#include "ubifs.h"
-
-#ifndef __BAREBOX__
-/*
- * 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 __BAREBOX__
-/**
- * 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