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Diffstat (limited to 'fs/ubifs/gc.c')
-rw-r--r-- | fs/ubifs/gc.c | 976 |
1 files changed, 0 insertions, 976 deletions
diff --git a/fs/ubifs/gc.c b/fs/ubifs/gc.c deleted file mode 100644 index 39f749dc82..0000000000 --- a/fs/ubifs/gc.c +++ /dev/null @@ -1,976 +0,0 @@ -/* - * 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 |