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Diffstat (limited to 'fs/ubifs/lprops.c')
| -rw-r--r-- | fs/ubifs/lprops.c | 842 |
1 files changed, 842 insertions, 0 deletions
diff --git a/fs/ubifs/lprops.c b/fs/ubifs/lprops.c new file mode 100644 index 0000000..8ce4949 --- /dev/null +++ b/fs/ubifs/lprops.c @@ -0,0 +1,842 @@ +/* + * 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 the functions that access LEB properties and their + * categories. LEBs are categorized based on the needs of UBIFS, and the + * categories are stored as either heaps or lists to provide a fast way of + * finding a LEB in a particular category. For example, UBIFS may need to find + * an empty LEB for the journal, or a very dirty LEB for garbage collection. + */ + +#include "ubifs.h" + +/** + * get_heap_comp_val - get the LEB properties value for heap comparisons. + * @lprops: LEB properties + * @cat: LEB category + */ +static int get_heap_comp_val(struct ubifs_lprops *lprops, int cat) +{ + switch (cat) { + case LPROPS_FREE: + return lprops->free; + case LPROPS_DIRTY_IDX: + return lprops->free + lprops->dirty; + default: + return lprops->dirty; + } +} + +/** + * move_up_lpt_heap - move a new heap entry up as far as possible. + * @c: UBIFS file-system description object + * @heap: LEB category heap + * @lprops: LEB properties to move + * @cat: LEB category + * + * New entries to a heap are added at the bottom and then moved up until the + * parent's value is greater. In the case of LPT's category heaps, the value + * is either the amount of free space or the amount of dirty space, depending + * on the category. + */ +static void move_up_lpt_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, + struct ubifs_lprops *lprops, int cat) +{ + int val1, val2, hpos; + + hpos = lprops->hpos; + if (!hpos) + return; /* Already top of the heap */ + val1 = get_heap_comp_val(lprops, cat); + /* Compare to parent and, if greater, move up the heap */ + do { + int ppos = (hpos - 1) / 2; + + val2 = get_heap_comp_val(heap->arr[ppos], cat); + if (val2 >= val1) + return; + /* Greater than parent so move up */ + heap->arr[ppos]->hpos = hpos; + heap->arr[hpos] = heap->arr[ppos]; + heap->arr[ppos] = lprops; + lprops->hpos = ppos; + hpos = ppos; + } while (hpos); +} + +/** + * adjust_lpt_heap - move a changed heap entry up or down the heap. + * @c: UBIFS file-system description object + * @heap: LEB category heap + * @lprops: LEB properties to move + * @hpos: heap position of @lprops + * @cat: LEB category + * + * Changed entries in a heap are moved up or down until the parent's value is + * greater. In the case of LPT's category heaps, the value is either the amount + * of free space or the amount of dirty space, depending on the category. + */ +static void adjust_lpt_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, + struct ubifs_lprops *lprops, int hpos, int cat) +{ + int val1, val2, val3, cpos; + + val1 = get_heap_comp_val(lprops, cat); + /* Compare to parent and, if greater than parent, move up the heap */ + if (hpos) { + int ppos = (hpos - 1) / 2; + + val2 = get_heap_comp_val(heap->arr[ppos], cat); + if (val1 > val2) { + /* Greater than parent so move up */ + while (1) { + heap->arr[ppos]->hpos = hpos; + heap->arr[hpos] = heap->arr[ppos]; + heap->arr[ppos] = lprops; + lprops->hpos = ppos; + hpos = ppos; + if (!hpos) + return; + ppos = (hpos - 1) / 2; + val2 = get_heap_comp_val(heap->arr[ppos], cat); + if (val1 <= val2) + return; + /* Still greater than parent so keep going */ + } + } + } + + /* Not greater than parent, so compare to children */ + while (1) { + /* Compare to left child */ + cpos = hpos * 2 + 1; + if (cpos >= heap->cnt) + return; + val2 = get_heap_comp_val(heap->arr[cpos], cat); + if (val1 < val2) { + /* Less than left child, so promote biggest child */ + if (cpos + 1 < heap->cnt) { + val3 = get_heap_comp_val(heap->arr[cpos + 1], + cat); + if (val3 > val2) + cpos += 1; /* Right child is bigger */ + } + heap->arr[cpos]->hpos = hpos; + heap->arr[hpos] = heap->arr[cpos]; + heap->arr[cpos] = lprops; + lprops->hpos = cpos; + hpos = cpos; + continue; + } + /* Compare to right child */ + cpos += 1; + if (cpos >= heap->cnt) + return; + val3 = get_heap_comp_val(heap->arr[cpos], cat); + if (val1 < val3) { + /* Less than right child, so promote right child */ + heap->arr[cpos]->hpos = hpos; + heap->arr[hpos] = heap->arr[cpos]; + heap->arr[cpos] = lprops; + lprops->hpos = cpos; + hpos = cpos; + continue; + } + return; + } +} + +/** + * add_to_lpt_heap - add LEB properties to a LEB category heap. + * @c: UBIFS file-system description object + * @lprops: LEB properties to add + * @cat: LEB category + * + * This function returns %1 if @lprops is added to the heap for LEB category + * @cat, otherwise %0 is returned because the heap is full. + */ +static int add_to_lpt_heap(struct ubifs_info *c, struct ubifs_lprops *lprops, + int cat) +{ + struct ubifs_lpt_heap *heap = &c->lpt_heap[cat - 1]; + + if (heap->cnt >= heap->max_cnt) { + const int b = LPT_HEAP_SZ / 2 - 1; + int cpos, val1, val2; + + /* Compare to some other LEB on the bottom of heap */ + /* Pick a position kind of randomly */ + cpos = (((size_t)lprops >> 4) & b) + b; + ubifs_assert(cpos >= b); + ubifs_assert(cpos < LPT_HEAP_SZ); + ubifs_assert(cpos < heap->cnt); + + val1 = get_heap_comp_val(lprops, cat); + val2 = get_heap_comp_val(heap->arr[cpos], cat); + if (val1 > val2) { + struct ubifs_lprops *lp; + + lp = heap->arr[cpos]; + lp->flags &= ~LPROPS_CAT_MASK; + lp->flags |= LPROPS_UNCAT; + list_add(&lp->list, &c->uncat_list); + lprops->hpos = cpos; + heap->arr[cpos] = lprops; + move_up_lpt_heap(c, heap, lprops, cat); + dbg_check_heap(c, heap, cat, lprops->hpos); + return 1; /* Added to heap */ + } + dbg_check_heap(c, heap, cat, -1); + return 0; /* Not added to heap */ + } else { + lprops->hpos = heap->cnt++; + heap->arr[lprops->hpos] = lprops; + move_up_lpt_heap(c, heap, lprops, cat); + dbg_check_heap(c, heap, cat, lprops->hpos); + return 1; /* Added to heap */ + } +} + +/** + * remove_from_lpt_heap - remove LEB properties from a LEB category heap. + * @c: UBIFS file-system description object + * @lprops: LEB properties to remove + * @cat: LEB category + */ +static void remove_from_lpt_heap(struct ubifs_info *c, + struct ubifs_lprops *lprops, int cat) +{ + struct ubifs_lpt_heap *heap; + int hpos = lprops->hpos; + + heap = &c->lpt_heap[cat - 1]; + ubifs_assert(hpos >= 0 && hpos < heap->cnt); + ubifs_assert(heap->arr[hpos] == lprops); + heap->cnt -= 1; + if (hpos < heap->cnt) { + heap->arr[hpos] = heap->arr[heap->cnt]; + heap->arr[hpos]->hpos = hpos; + adjust_lpt_heap(c, heap, heap->arr[hpos], hpos, cat); + } + dbg_check_heap(c, heap, cat, -1); +} + +/** + * lpt_heap_replace - replace lprops in a category heap. + * @c: UBIFS file-system description object + * @old_lprops: LEB properties to replace + * @new_lprops: LEB properties with which to replace + * @cat: LEB category + * + * During commit it is sometimes necessary to copy a pnode (see dirty_cow_pnode) + * and the lprops that the pnode contains. When that happens, references in + * the category heaps to those lprops must be updated to point to the new + * lprops. This function does that. + */ +static void lpt_heap_replace(struct ubifs_info *c, + struct ubifs_lprops *old_lprops, + struct ubifs_lprops *new_lprops, int cat) +{ + struct ubifs_lpt_heap *heap; + int hpos = new_lprops->hpos; + + heap = &c->lpt_heap[cat - 1]; + heap->arr[hpos] = new_lprops; +} + +/** + * ubifs_add_to_cat - add LEB properties to a category list or heap. + * @c: UBIFS file-system description object + * @lprops: LEB properties to add + * @cat: LEB category to which to add + * + * LEB properties are categorized to enable fast find operations. + */ +void ubifs_add_to_cat(struct ubifs_info *c, struct ubifs_lprops *lprops, + int cat) +{ + switch (cat) { + case LPROPS_DIRTY: + case LPROPS_DIRTY_IDX: + case LPROPS_FREE: + if (add_to_lpt_heap(c, lprops, cat)) + break; + /* No more room on heap so make it uncategorized */ + cat = LPROPS_UNCAT; + /* Fall through */ + case LPROPS_UNCAT: + list_add(&lprops->list, &c->uncat_list); + break; + case LPROPS_EMPTY: + list_add(&lprops->list, &c->empty_list); + break; + case LPROPS_FREEABLE: + list_add(&lprops->list, &c->freeable_list); + c->freeable_cnt += 1; + break; + case LPROPS_FRDI_IDX: + list_add(&lprops->list, &c->frdi_idx_list); + break; + default: + ubifs_assert(0); + } + lprops->flags &= ~LPROPS_CAT_MASK; + lprops->flags |= cat; +} + +/** + * ubifs_remove_from_cat - remove LEB properties from a category list or heap. + * @c: UBIFS file-system description object + * @lprops: LEB properties to remove + * @cat: LEB category from which to remove + * + * LEB properties are categorized to enable fast find operations. + */ +static void ubifs_remove_from_cat(struct ubifs_info *c, + struct ubifs_lprops *lprops, int cat) +{ + switch (cat) { + case LPROPS_DIRTY: + case LPROPS_DIRTY_IDX: + case LPROPS_FREE: + remove_from_lpt_heap(c, lprops, cat); + break; + case LPROPS_FREEABLE: + c->freeable_cnt -= 1; + ubifs_assert(c->freeable_cnt >= 0); + /* Fall through */ + case LPROPS_UNCAT: + case LPROPS_EMPTY: + case LPROPS_FRDI_IDX: + ubifs_assert(!list_empty(&lprops->list)); + list_del(&lprops->list); + break; + default: + ubifs_assert(0); + } +} + +/** + * ubifs_replace_cat - replace lprops in a category list or heap. + * @c: UBIFS file-system description object + * @old_lprops: LEB properties to replace + * @new_lprops: LEB properties with which to replace + * + * During commit it is sometimes necessary to copy a pnode (see dirty_cow_pnode) + * and the lprops that the pnode contains. When that happens, references in + * category lists and heaps must be replaced. This function does that. + */ +void ubifs_replace_cat(struct ubifs_info *c, struct ubifs_lprops *old_lprops, + struct ubifs_lprops *new_lprops) +{ + int cat; + + cat = new_lprops->flags & LPROPS_CAT_MASK; + switch (cat) { + case LPROPS_DIRTY: + case LPROPS_DIRTY_IDX: + case LPROPS_FREE: + lpt_heap_replace(c, old_lprops, new_lprops, cat); + break; + case LPROPS_UNCAT: + case LPROPS_EMPTY: + case LPROPS_FREEABLE: + case LPROPS_FRDI_IDX: + list_replace(&old_lprops->list, &new_lprops->list); + break; + default: + ubifs_assert(0); + } +} + +/** + * ubifs_ensure_cat - ensure LEB properties are categorized. + * @c: UBIFS file-system description object + * @lprops: LEB properties + * + * A LEB may have fallen off of the bottom of a heap, and ended up as + * uncategorized even though it has enough space for us now. If that is the case + * this function will put the LEB back onto a heap. + */ +void ubifs_ensure_cat(struct ubifs_info *c, struct ubifs_lprops *lprops) +{ + int cat = lprops->flags & LPROPS_CAT_MASK; + + if (cat != LPROPS_UNCAT) + return; + cat = ubifs_categorize_lprops(c, lprops); + if (cat == LPROPS_UNCAT) + return; + ubifs_remove_from_cat(c, lprops, LPROPS_UNCAT); + ubifs_add_to_cat(c, lprops, cat); +} + +/** + * ubifs_categorize_lprops - categorize LEB properties. + * @c: UBIFS file-system description object + * @lprops: LEB properties to categorize + * + * LEB properties are categorized to enable fast find operations. This function + * returns the LEB category to which the LEB properties belong. Note however + * that if the LEB category is stored as a heap and the heap is full, the + * LEB properties may have their category changed to %LPROPS_UNCAT. + */ +int ubifs_categorize_lprops(const struct ubifs_info *c, + const struct ubifs_lprops *lprops) +{ + if (lprops->flags & LPROPS_TAKEN) + return LPROPS_UNCAT; + + if (lprops->free == c->leb_size) { + ubifs_assert(!(lprops->flags & LPROPS_INDEX)); + return LPROPS_EMPTY; + } + + if (lprops->free + lprops->dirty == c->leb_size) { + if (lprops->flags & LPROPS_INDEX) + return LPROPS_FRDI_IDX; + else + return LPROPS_FREEABLE; + } + + if (lprops->flags & LPROPS_INDEX) { + if (lprops->dirty + lprops->free >= c->min_idx_node_sz) + return LPROPS_DIRTY_IDX; + } else { + if (lprops->dirty >= c->dead_wm && + lprops->dirty > lprops->free) + return LPROPS_DIRTY; + if (lprops->free > 0) + return LPROPS_FREE; + } + + return LPROPS_UNCAT; +} + +/** + * change_category - change LEB properties category. + * @c: UBIFS file-system description object + * @lprops: LEB properties to recategorize + * + * LEB properties are categorized to enable fast find operations. When the LEB + * properties change they must be recategorized. + */ +static void change_category(struct ubifs_info *c, struct ubifs_lprops *lprops) +{ + int old_cat = lprops->flags & LPROPS_CAT_MASK; + int new_cat = ubifs_categorize_lprops(c, lprops); + + if (old_cat == new_cat) { + struct ubifs_lpt_heap *heap = &c->lpt_heap[new_cat - 1]; + + /* lprops on a heap now must be moved up or down */ + if (new_cat < 1 || new_cat > LPROPS_HEAP_CNT) + return; /* Not on a heap */ + heap = &c->lpt_heap[new_cat - 1]; + adjust_lpt_heap(c, heap, lprops, lprops->hpos, new_cat); + } else { + ubifs_remove_from_cat(c, lprops, old_cat); + ubifs_add_to_cat(c, lprops, new_cat); + } +} + +/** + * calc_dark - calculate LEB dark space size. + * @c: the UBIFS file-system description object + * @spc: amount of free and dirty space in the LEB + * + * This function calculates amount of dark space in an LEB which has @spc bytes + * of free and dirty space. Returns the calculations result. + * + * Dark space is the space which is not always usable - it depends on which + * nodes are written in which order. E.g., if an LEB has only 512 free bytes, + * it is dark space, because it cannot fit a large data node. So UBIFS cannot + * count on this LEB and treat these 512 bytes as usable because it is not true + * if, for example, only big chunks of uncompressible data will be written to + * the FS. + */ +static int calc_dark(struct ubifs_info *c, int spc) +{ + ubifs_assert(!(spc & 7)); + + if (spc < c->dark_wm) + return spc; + + /* + * If we have slightly more space then the dark space watermark, we can + * anyway safely assume it we'll be able to write a node of the + * smallest size there. + */ + if (spc - c->dark_wm < MIN_WRITE_SZ) + return spc - MIN_WRITE_SZ; + + return c->dark_wm; +} + +/** + * is_lprops_dirty - determine if LEB properties are dirty. + * @c: the UBIFS file-system description object + * @lprops: LEB properties to test + */ +static int is_lprops_dirty(struct ubifs_info *c, struct ubifs_lprops *lprops) +{ + struct ubifs_pnode *pnode; + int pos; + + pos = (lprops->lnum - c->main_first) & (UBIFS_LPT_FANOUT - 1); + pnode = (struct ubifs_pnode *)container_of(lprops - pos, + struct ubifs_pnode, + lprops[0]); + return !test_bit(COW_ZNODE, &pnode->flags) && + test_bit(DIRTY_CNODE, &pnode->flags); +} + +/** + * ubifs_change_lp - change LEB properties. + * @c: the UBIFS file-system description object + * @lp: LEB properties to change + * @free: new free space amount + * @dirty: new dirty space amount + * @flags: new flags + * @idx_gc_cnt: change to the count of idx_gc list + * + * This function changes LEB properties (@free, @dirty or @flag). However, the + * property which has the %LPROPS_NC value is not changed. Returns a pointer to + * the updated LEB properties on success and a negative error code on failure. + * + * Note, the LEB properties may have had to be copied (due to COW) and + * consequently the pointer returned may not be the same as the pointer + * passed. + */ +const struct ubifs_lprops *ubifs_change_lp(struct ubifs_info *c, + const struct ubifs_lprops *lp, + int free, int dirty, int flags, + int idx_gc_cnt) +{ + /* + * This is the only function that is allowed to change lprops, so we + * discard the const qualifier. + */ + struct ubifs_lprops *lprops = (struct ubifs_lprops *)lp; + + dbg_lp("LEB %d, free %d, dirty %d, flags %d", + lprops->lnum, free, dirty, flags); + + ubifs_assert(mutex_is_locked(&c->lp_mutex)); + ubifs_assert(c->lst.empty_lebs >= 0 && + c->lst.empty_lebs <= c->main_lebs); + ubifs_assert(c->freeable_cnt >= 0); + ubifs_assert(c->freeable_cnt <= c->main_lebs); + ubifs_assert(c->lst.taken_empty_lebs >= 0); + ubifs_assert(c->lst.taken_empty_lebs <= c->lst.empty_lebs); + ubifs_assert(!(c->lst.total_free & 7) && !(c->lst.total_dirty & 7)); + ubifs_assert(!(c->lst.total_dead & 7) && !(c->lst.total_dark & 7)); + ubifs_assert(!(c->lst.total_used & 7)); + ubifs_assert(free == LPROPS_NC || free >= 0); + ubifs_assert(dirty == LPROPS_NC || dirty >= 0); + + if (!is_lprops_dirty(c, lprops)) { + lprops = ubifs_lpt_lookup_dirty(c, lprops->lnum); + if (IS_ERR(lprops)) + return lprops; + } else + ubifs_assert(lprops == ubifs_lpt_lookup_dirty(c, lprops->lnum)); + + ubifs_assert(!(lprops->free & 7) && !(lprops->dirty & 7)); + + spin_lock(&c->space_lock); + if ((lprops->flags & LPROPS_TAKEN) && lprops->free == c->leb_size) + c->lst.taken_empty_lebs -= 1; + + if (!(lprops->flags & LPROPS_INDEX)) { + int old_spc; + + old_spc = lprops->free + lprops->dirty; + if (old_spc < c->dead_wm) + c->lst.total_dead -= old_spc; + else + c->lst.total_dark -= calc_dark(c, old_spc); + + c->lst.total_used -= c->leb_size - old_spc; + } + + if (free != LPROPS_NC) { + free = ALIGN(free, 8); + c->lst.total_free += free - lprops->free; + + /* Increase or decrease empty LEBs counter if needed */ + if (free == c->leb_size) { + if (lprops->free != c->leb_size) + c->lst.empty_lebs += 1; + } else if (lprops->free == c->leb_size) + c->lst.empty_lebs -= 1; + lprops->free = free; + } + + if (dirty != LPROPS_NC) { + dirty = ALIGN(dirty, 8); + c->lst.total_dirty += dirty - lprops->dirty; + lprops->dirty = dirty; + } + + if (flags != LPROPS_NC) { + /* Take care about indexing LEBs counter if needed */ + if ((lprops->flags & LPROPS_INDEX)) { + if (!(flags & LPROPS_INDEX)) + c->lst.idx_lebs -= 1; + } else if (flags & LPROPS_INDEX) + c->lst.idx_lebs += 1; + lprops->flags = flags; + } + + if (!(lprops->flags & LPROPS_INDEX)) { + int new_spc; + + new_spc = lprops->free + lprops->dirty; + if (new_spc < c->dead_wm) + c->lst.total_dead += new_spc; + else + c->lst.total_dark += calc_dark(c, new_spc); + + c->lst.total_used += c->leb_size - new_spc; + } + + if ((lprops->flags & LPROPS_TAKEN) && lprops->free == c->leb_size) + c->lst.taken_empty_lebs += 1; + + change_category(c, lprops); + c->idx_gc_cnt += idx_gc_cnt; + spin_unlock(&c->space_lock); + return lprops; +} + +/** + * ubifs_get_lp_stats - get lprops statistics. + * @c: UBIFS file-system description object + * @st: return statistics + */ +void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *lst) +{ + spin_lock(&c->space_lock); + memcpy(lst, &c->lst, sizeof(struct ubifs_lp_stats)); + spin_unlock(&c->space_lock); +} + +/** + * ubifs_change_one_lp - change LEB properties. + * @c: the UBIFS file-system description object + * @lnum: LEB to change properties for + * @free: amount of free space + * @dirty: amount of dirty space + * @flags_set: flags to set + * @flags_clean: flags to clean + * @idx_gc_cnt: change to the count of idx_gc list + * + * This function changes properties of LEB @lnum. It is a helper wrapper over + * 'ubifs_change_lp()' which hides lprops get/release. The arguments are the + * same as in case of 'ubifs_change_lp()'. Returns zero in case of success and + * a negative error code in case of failure. + */ +int ubifs_change_one_lp(struct ubifs_info *c, int lnum, int free, int dirty, + int flags_set, int flags_clean, int idx_gc_cnt) +{ + int err = 0, flags; + const struct ubifs_lprops *lp; + + ubifs_get_lprops(c); + + lp = ubifs_lpt_lookup_dirty(c, lnum); + if (IS_ERR(lp)) { + err = PTR_ERR(lp); + goto out; + } + + flags = (lp->flags | flags_set) & ~flags_clean; + lp = ubifs_change_lp(c, lp, free, dirty, flags, idx_gc_cnt); + if (IS_ERR(lp)) + err = PTR_ERR(lp); + +out: + ubifs_release_lprops(c); + return err; +} + +/** + * ubifs_update_one_lp - update LEB properties. + * @c: the UBIFS file-system description object + * @lnum: LEB to change properties for + * @free: amount of free space + * @dirty: amount of dirty space to add + * @flags_set: flags to set + * @flags_clean: flags to clean + * + * This function is the same as 'ubifs_change_one_lp()' but @dirty is added to + * current dirty space, not substitutes it. + */ +int ubifs_update_one_lp(struct ubifs_info *c, int lnum, int free, int dirty, + int flags_set, int flags_clean) +{ + int err = 0, flags; + const struct ubifs_lprops *lp; + + ubifs_get_lprops(c); + + lp = ubifs_lpt_lookup_dirty(c, lnum); + if (IS_ERR(lp)) { + err = PTR_ERR(lp); + goto out; + } + + flags = (lp->flags | flags_set) & ~flags_clean; + lp = ubifs_change_lp(c, lp, free, lp->dirty + dirty, flags, 0); + if (IS_ERR(lp)) + err = PTR_ERR(lp); + +out: + ubifs_release_lprops(c); + return err; +} + +/** + * ubifs_read_one_lp - read LEB properties. + * @c: the UBIFS file-system description object + * @lnum: LEB to read properties for + * @lp: where to store read properties + * + * This helper function reads properties of a LEB @lnum and stores them in @lp. + * Returns zero in case of success and a negative error code in case of + * failure. + */ +int ubifs_read_one_lp(struct ubifs_info *c, int lnum, struct ubifs_lprops *lp) +{ + int err = 0; + const struct ubifs_lprops *lpp; + + ubifs_get_lprops(c); + + lpp = ubifs_lpt_lookup(c, lnum); + if (IS_ERR(lpp)) { + err = PTR_ERR(lpp); + goto out; + } + + memcpy(lp, lpp, sizeof(struct ubifs_lprops)); + +out: + ubifs_release_lprops(c); + return err; +} + +/** + * ubifs_fast_find_free - try to find a LEB with free space quickly. + * @c: the UBIFS file-system description object + * + * This function returns LEB properties for a LEB with free space or %NULL if + * the function is unable to find a LEB quickly. + */ +const struct ubifs_lprops *ubifs_fast_find_free(struct ubifs_info *c) +{ + struct ubifs_lprops *lprops; + struct ubifs_lpt_heap *heap; + + ubifs_assert(mutex_is_locked(&c->lp_mutex)); + + heap = &c->lpt_heap[LPROPS_FREE - 1]; + if (heap->cnt == 0) + return NULL; + + lprops = heap->arr[0]; + ubifs_assert(!(lprops->flags & LPROPS_TAKEN)); + ubifs_assert(!(lprops->flags & LPROPS_INDEX)); + return lprops; +} + +/** + * ubifs_fast_find_empty - try to find an empty LEB quickly. + * @c: the UBIFS file-system description object + * + * This function returns LEB properties for an empty LEB or %NULL if the + * function is unable to find an empty LEB quickly. + */ +const struct ubifs_lprops *ubifs_fast_find_empty(struct ubifs_info *c) +{ + struct ubifs_lprops *lprops; + + ubifs_assert(mutex_is_locked(&c->lp_mutex)); + + if (list_empty(&c->empty_list)) + return NULL; + + lprops = list_entry(c->empty_list.next, struct ubifs_lprops, list); + ubifs_assert(!(lprops->flags & LPROPS_TAKEN)); + ubifs_assert(!(lprops->flags & LPROPS_INDEX)); + ubifs_assert(lprops->free == c->leb_size); + return lprops; +} + +/** + * ubifs_fast_find_freeable - try to find a freeable LEB quickly. + * @c: the UBIFS file-system description object + * + * This function returns LEB properties for a freeable LEB or %NULL if the + * function is unable to find a freeable LEB quickly. + */ +const struct ubifs_lprops *ubifs_fast_find_freeable(struct ubifs_info *c) +{ + struct ubifs_lprops *lprops; + + ubifs_assert(mutex_is_locked(&c->lp_mutex)); + + if (list_empty(&c->freeable_list)) + return NULL; + + lprops = list_entry(c->freeable_list.next, struct ubifs_lprops, list); + ubifs_assert(!(lprops->flags & LPROPS_TAKEN)); + ubifs_assert(!(lprops->flags & LPROPS_INDEX)); + ubifs_assert(lprops->free + lprops->dirty == c->leb_size); + ubifs_assert(c->freeable_cnt > 0); + return lprops; +} + +/** + * ubifs_fast_find_frdi_idx - try to find a freeable index LEB quickly. + * @c: the UBIFS file-system description object + * + * This function returns LEB properties for a freeable index LEB or %NULL if the + * function is unable to find a freeable index LEB quickly. + */ +const struct ubifs_lprops *ubifs_fast_find_frdi_idx(struct ubifs_info *c) +{ + struct ubifs_lprops *lprops; + + ubifs_assert(mutex_is_locked(&c->lp_mutex)); + + if (list_empty(&c->frdi_idx_list)) + return NULL; + + lprops = list_entry(c->frdi_idx_list.next, struct ubifs_lprops, list); + ubifs_assert(!(lprops->flags & LPROPS_TAKEN)); + ubifs_assert((lprops->flags & LPROPS_INDEX)); + ubifs_assert(lprops->free + lprops->dirty == c->leb_size); + return lprops; +} |