/*
|
* 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 __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
|
