X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fext3%2Fballoc.c;h=ff6c799c7fbe5df201f801a691df352e863be7de;hb=6a77f38946aaee1cd85eeec6cf4229b204c15071;hp=bc2a9b82564b504f835f1c841f21d853c97cefb0;hpb=87fc8d1bb10cd459024a742c6a10961fefcef18f;p=linux-2.6.git diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c index bc2a9b825..ff6c799c7 100644 --- a/fs/ext3/balloc.c +++ b/fs/ext3/balloc.c @@ -19,7 +19,6 @@ #include #include #include -#include #include /* @@ -56,9 +55,10 @@ struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb, return NULL; } + smp_rmb(); - group_desc = block_group / EXT3_DESC_PER_BLOCK(sb); - desc = block_group % EXT3_DESC_PER_BLOCK(sb); + group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb); + desc = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1); if (!EXT3_SB(sb)->s_group_desc[group_desc]) { ext3_error (sb, "ext3_get_group_desc", "Group descriptor not loaded - " @@ -98,10 +98,186 @@ read_block_bitmap(struct super_block *sb, unsigned int block_group) error_out: return bh; } +/* + * The reservation window structure operations + * -------------------------------------------- + * Operations include: + * dump, find, add, remove, is_empty, find_next_reservable_window, etc. + * + * We use sorted double linked list for the per-filesystem reservation + * window list. (like in vm_region). + * + * Initially, we keep those small operations in the abstract functions, + * so later if we need a better searching tree than double linked-list, + * we could easily switch to that without changing too much + * code. + */ +#if 0 +static void __rsv_window_dump(struct rb_root *root, int verbose, + const char *fn) +{ + struct rb_node *n; + struct ext3_reserve_window_node *rsv, *prev; + int bad; + +restart: + n = rb_first(root); + bad = 0; + prev = NULL; + + printk("Block Allocation Reservation Windows Map (%s):\n", fn); + while (n) { + rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node); + if (verbose) + printk("reservation window 0x%p " + "start: %d, end: %d\n", + rsv, rsv->rsv_start, rsv->rsv_end); + if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) { + printk("Bad reservation %p (start >= end)\n", + rsv); + bad = 1; + } + if (prev && prev->rsv_end >= rsv->rsv_start) { + printk("Bad reservation %p (prev->end >= start)\n", + rsv); + bad = 1; + } + if (bad) { + if (!verbose) { + printk("Restarting reservation walk in verbose mode\n"); + verbose = 1; + goto restart; + } + } + n = rb_next(n); + prev = rsv; + } + printk("Window map complete.\n"); + if (bad) + BUG(); +} +#define rsv_window_dump(root, verbose) \ + __rsv_window_dump((root), (verbose), __FUNCTION__) +#else +#define rsv_window_dump(root, verbose) do {} while (0) +#endif + +static int +goal_in_my_reservation(struct ext3_reserve_window *rsv, int goal, + unsigned int group, struct super_block * sb) +{ + unsigned long group_first_block, group_last_block; + + group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) + + group * EXT3_BLOCKS_PER_GROUP(sb); + group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; + + if ((rsv->_rsv_start > group_last_block) || + (rsv->_rsv_end < group_first_block)) + return 0; + if ((goal >= 0) && ((goal + group_first_block < rsv->_rsv_start) + || (goal + group_first_block > rsv->_rsv_end))) + return 0; + return 1; +} + +/* + * Find the reserved window which includes the goal, or the previous one + * if the goal is not in any window. + * Returns NULL if there are no windows or if all windows start after the goal. + */ +static struct ext3_reserve_window_node * +search_reserve_window(struct rb_root *root, unsigned long goal) +{ + struct rb_node *n = root->rb_node; + struct ext3_reserve_window_node *rsv; + + if (!n) + return NULL; + + do { + rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node); + + if (goal < rsv->rsv_start) + n = n->rb_left; + else if (goal > rsv->rsv_end) + n = n->rb_right; + else + return rsv; + } while (n); + /* + * We've fallen off the end of the tree: the goal wasn't inside + * any particular node. OK, the previous node must be to one + * side of the interval containing the goal. If it's the RHS, + * we need to back up one. + */ + if (rsv->rsv_start > goal) { + n = rb_prev(&rsv->rsv_node); + rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node); + } + return rsv; +} + +void ext3_rsv_window_add(struct super_block *sb, + struct ext3_reserve_window_node *rsv) +{ + struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root; + struct rb_node *node = &rsv->rsv_node; + unsigned int start = rsv->rsv_start; + + struct rb_node ** p = &root->rb_node; + struct rb_node * parent = NULL; + struct ext3_reserve_window_node *this; + + while (*p) + { + parent = *p; + this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node); + + if (start < this->rsv_start) + p = &(*p)->rb_left; + else if (start > this->rsv_end) + p = &(*p)->rb_right; + else + BUG(); + } + + rb_link_node(node, parent, p); + rb_insert_color(node, root); +} + +static void rsv_window_remove(struct super_block *sb, + struct ext3_reserve_window_node *rsv) +{ + rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; + rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED; + atomic_set(&rsv->rsv_alloc_hit, 0); + rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root); +} + +static inline int rsv_is_empty(struct ext3_reserve_window *rsv) +{ + /* a valid reservation end block could not be 0 */ + return (rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED); +} + +void ext3_discard_reservation(struct inode *inode) +{ + struct ext3_inode_info *ei = EXT3_I(inode); + struct ext3_reserve_window_node *rsv = &ei->i_rsv_window; + spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock; + + if (!rsv_is_empty(&rsv->rsv_window)) { + spin_lock(rsv_lock); + rsv_window_remove(inode->i_sb, rsv); + spin_unlock(rsv_lock); + } +} /* Free given blocks, update quota and i_blocks field */ -void ext3_free_blocks (handle_t *handle, struct inode * inode, - unsigned long block, unsigned long count) +void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb, + unsigned long block, unsigned long count, + int *pdquot_freed_blocks) { struct buffer_head *bitmap_bh = NULL; struct buffer_head *gd_bh; @@ -109,18 +285,12 @@ void ext3_free_blocks (handle_t *handle, struct inode * inode, unsigned long bit; unsigned long i; unsigned long overflow; - struct super_block * sb; struct ext3_group_desc * gdp; struct ext3_super_block * es; struct ext3_sb_info *sbi; int err = 0, ret; - int dquot_freed_blocks = 0; - sb = inode->i_sb; - if (!sb) { - printk ("ext3_free_blocks: nonexistent device"); - return; - } + *pdquot_freed_blocks = 0; sbi = EXT3_SB(sb); es = EXT3_SB(sb)->s_es; if (block < le32_to_cpu(es->s_first_data_block) || @@ -209,6 +379,11 @@ do_more: } jbd_lock_bh_state(bitmap_bh); #endif + if (need_resched()) { + jbd_unlock_bh_state(bitmap_bh); + cond_resched(); + jbd_lock_bh_state(bitmap_bh); + } /* @@@ This prevents newly-allocated data from being * freed and then reallocated within the same * transaction. @@ -247,7 +422,7 @@ do_more: jbd_lock_bh_state(bitmap_bh); BUFFER_TRACE(bitmap_bh, "bit already cleared"); } else { - dquot_freed_blocks++; + (*pdquot_freed_blocks)++; } } jbd_unlock_bh_state(bitmap_bh); @@ -255,7 +430,7 @@ do_more: spin_lock(sb_bgl_lock(sbi, block_group)); gdp->bg_free_blocks_count = cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) + - dquot_freed_blocks); + *pdquot_freed_blocks); spin_unlock(sb_bgl_lock(sbi, block_group)); percpu_counter_mod(&sbi->s_freeblocks_counter, count); @@ -277,6 +452,22 @@ do_more: error_return: brelse(bitmap_bh); ext3_std_error(sb, err); + return; +} + +/* Free given blocks, update quota and i_blocks field */ +void ext3_free_blocks(handle_t *handle, struct inode *inode, + unsigned long block, unsigned long count) +{ + struct super_block * sb; + int dquot_freed_blocks; + + sb = inode->i_sb; + if (!sb) { + printk ("ext3_free_blocks: nonexistent device"); + return; + } + ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks); if (dquot_freed_blocks) { DLIMIT_FREE_BLOCK(sb, inode->i_xid, dquot_freed_blocks); DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); @@ -300,7 +491,7 @@ error_return: * data-writes at some point, and disable it for metadata allocations or * sync-data inodes. */ -static inline int ext3_test_allocatable(int nr, struct buffer_head *bh) +static int ext3_test_allocatable(int nr, struct buffer_head *bh) { int ret; struct journal_head *jh = bh2jh(bh); @@ -317,6 +508,33 @@ static inline int ext3_test_allocatable(int nr, struct buffer_head *bh) return ret; } +static int +bitmap_search_next_usable_block(int start, struct buffer_head *bh, + int maxblocks) +{ + int next; + struct journal_head *jh = bh2jh(bh); + + /* + * The bitmap search --- search forward alternately through the actual + * bitmap and the last-committed copy until we find a bit free in + * both + */ + while (start < maxblocks) { + next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start); + if (next >= maxblocks) + return -1; + if (ext3_test_allocatable(next, bh)) + return next; + jbd_lock_bh_state(bh); + if (jh->b_committed_data) + start = ext3_find_next_zero_bit(jh->b_committed_data, + maxblocks, next); + jbd_unlock_bh_state(bh); + } + return -1; +} + /* * Find an allocatable block in a bitmap. We honour both the bitmap and * its last-committed copy (if that exists), and perform the "most @@ -329,7 +547,6 @@ find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) { int here, next; char *p, *r; - struct journal_head *jh = bh2jh(bh); if (start > 0) { /* @@ -341,6 +558,8 @@ find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) * next 64-bit boundary is simple.. */ int end_goal = (start + 63) & ~63; + if (end_goal > maxblocks) + end_goal = maxblocks; here = ext3_find_next_zero_bit(bh->b_data, end_goal, start); if (here < end_goal && ext3_test_allocatable(here, bh)) return here; @@ -355,7 +574,7 @@ find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) r = memscan(p, 0, (maxblocks - here + 7) >> 3); next = (r - ((char *)bh->b_data)) << 3; - if (next < maxblocks && ext3_test_allocatable(next, bh)) + if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh)) return next; /* @@ -363,19 +582,8 @@ find_next_usable_block(int start, struct buffer_head *bh, int maxblocks) * bitmap and the last-committed copy until we find a bit free in * both */ - while (here < maxblocks) { - next = ext3_find_next_zero_bit(bh->b_data, maxblocks, here); - if (next >= maxblocks) - return -1; - if (ext3_test_allocatable(next, bh)) - return next; - jbd_lock_bh_state(bh); - if (jh->b_committed_data) - here = ext3_find_next_zero_bit(jh->b_committed_data, - maxblocks, next); - jbd_unlock_bh_state(bh); - } - return -1; + here = bitmap_search_next_usable_block(here, bh, maxblocks); + return here; } /* @@ -411,62 +619,484 @@ claim_block(spinlock_t *lock, int block, struct buffer_head *bh) */ static int ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group, - struct buffer_head *bitmap_bh, int goal, int *errp) + struct buffer_head *bitmap_bh, int goal, struct ext3_reserve_window *my_rsv) { - int i; - int fatal; - int credits = 0; - - *errp = 0; - - /* - * Make sure we use undo access for the bitmap, because it is critical - * that we do the frozen_data COW on bitmap buffers in all cases even - * if the buffer is in BJ_Forget state in the committing transaction. - */ - BUFFER_TRACE(bitmap_bh, "get undo access for new block"); - fatal = ext3_journal_get_undo_access(handle, bitmap_bh, &credits); - if (fatal) { - *errp = fatal; - goto fail; + int group_first_block, start, end; + + /* we do allocation within the reservation window if we have a window */ + if (my_rsv) { + group_first_block = + le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) + + group * EXT3_BLOCKS_PER_GROUP(sb); + if (my_rsv->_rsv_start >= group_first_block) + start = my_rsv->_rsv_start - group_first_block; + else + /* reservation window cross group boundary */ + start = 0; + end = my_rsv->_rsv_end - group_first_block + 1; + if (end > EXT3_BLOCKS_PER_GROUP(sb)) + /* reservation window crosses group boundary */ + end = EXT3_BLOCKS_PER_GROUP(sb); + if ((start <= goal) && (goal < end)) + start = goal; + else + goal = -1; + } else { + if (goal > 0) + start = goal; + else + start = 0; + end = EXT3_BLOCKS_PER_GROUP(sb); } + BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb)); + repeat: if (goal < 0 || !ext3_test_allocatable(goal, bitmap_bh)) { - goal = find_next_usable_block(goal, bitmap_bh, - EXT3_BLOCKS_PER_GROUP(sb)); + goal = find_next_usable_block(start, bitmap_bh, end); if (goal < 0) goto fail_access; - - for (i = 0; i < 7 && goal > 0 && - ext3_test_allocatable(goal - 1, bitmap_bh); - i++, goal--); + if (!my_rsv) { + int i; + + for (i = 0; i < 7 && goal > start && + ext3_test_allocatable(goal - 1, + bitmap_bh); + i++, goal--) + ; + } } + start = goal; if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) { /* * The block was allocated by another thread, or it was * allocated and then freed by another thread */ + start++; goal++; - if (goal >= EXT3_BLOCKS_PER_GROUP(sb)) + if (start >= end) goto fail_access; goto repeat; } + return goal; +fail_access: + return -1; +} - BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for bitmap block"); - fatal = ext3_journal_dirty_metadata(handle, bitmap_bh); +/** + * find_next_reservable_window(): + * find a reservable space within the given range. + * It does not allocate the reservation window for now: + * alloc_new_reservation() will do the work later. + * + * @search_head: the head of the searching list; + * This is not necessarily the list head of the whole filesystem + * + * We have both head and start_block to assist the search + * for the reservable space. The list starts from head, + * but we will shift to the place where start_block is, + * then start from there, when looking for a reservable space. + * + * @size: the target new reservation window size + * + * @group_first_block: the first block we consider to start + * the real search from + * + * @last_block: + * the maximum block number that our goal reservable space + * could start from. This is normally the last block in this + * group. The search will end when we found the start of next + * possible reservable space is out of this boundary. + * This could handle the cross boundary reservation window + * request. + * + * basically we search from the given range, rather than the whole + * reservation double linked list, (start_block, last_block) + * to find a free region that is of my size and has not + * been reserved. + * + * on succeed, it returns the reservation window to be appended to. + * failed, return NULL. + */ +static struct ext3_reserve_window_node *find_next_reservable_window( + struct ext3_reserve_window_node *search_head, + unsigned long size, int *start_block, + int last_block) +{ + struct rb_node *next; + struct ext3_reserve_window_node *rsv, *prev; + int cur; + + /* TODO: make the start of the reservation window byte-aligned */ + /* cur = *start_block & ~7;*/ + cur = *start_block; + rsv = search_head; + if (!rsv) + return NULL; + + while (1) { + if (cur <= rsv->rsv_end) + cur = rsv->rsv_end + 1; + + /* TODO? + * in the case we could not find a reservable space + * that is what is expected, during the re-search, we could + * remember what's the largest reservable space we could have + * and return that one. + * + * For now it will fail if we could not find the reservable + * space with expected-size (or more)... + */ + if (cur > last_block) + return NULL; /* fail */ + + prev = rsv; + next = rb_next(&rsv->rsv_node); + rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node); + + /* + * Reached the last reservation, we can just append to the + * previous one. + */ + if (!next) + break; + + if (cur + size <= rsv->rsv_start) { + /* + * Found a reserveable space big enough. We could + * have a reservation across the group boundary here + */ + break; + } + } + /* + * we come here either : + * when we reach the end of the whole list, + * and there is empty reservable space after last entry in the list. + * append it to the end of the list. + * + * or we found one reservable space in the middle of the list, + * return the reservation window that we could append to. + * succeed. + */ + *start_block = cur; + return prev; +} + +/** + * alloc_new_reservation()--allocate a new reservation window + * + * To make a new reservation, we search part of the filesystem + * reservation list (the list that inside the group). We try to + * allocate a new reservation window near the allocation goal, + * or the beginning of the group, if there is no goal. + * + * We first find a reservable space after the goal, then from + * there, we check the bitmap for the first free block after + * it. If there is no free block until the end of group, then the + * whole group is full, we failed. Otherwise, check if the free + * block is inside the expected reservable space, if so, we + * succeed. + * If the first free block is outside the reservable space, then + * start from the first free block, we search for next available + * space, and go on. + * + * on succeed, a new reservation will be found and inserted into the list + * It contains at least one free block, and it does not overlap with other + * reservation windows. + * + * failed: we failed to find a reservation window in this group + * + * @rsv: the reservation + * + * @goal: The goal (group-relative). It is where the search for a + * free reservable space should start from. + * if we have a goal(goal >0 ), then start from there, + * no goal(goal = -1), we start from the first block + * of the group. + * + * @sb: the super block + * @group: the group we are trying to allocate in + * @bitmap_bh: the block group block bitmap + */ +static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv, + int goal, struct super_block *sb, + unsigned int group, struct buffer_head *bitmap_bh) +{ + struct ext3_reserve_window_node *search_head; + int group_first_block, group_end_block, start_block; + int first_free_block; + int reservable_space_start; + struct ext3_reserve_window_node *prev_rsv; + struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root; + unsigned long size; + + group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) + + group * EXT3_BLOCKS_PER_GROUP(sb); + group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; + + if (goal < 0) + start_block = group_first_block; + else + start_block = goal + group_first_block; + + size = atomic_read(&my_rsv->rsv_goal_size); + if (!rsv_is_empty(&my_rsv->rsv_window)) { + /* + * if the old reservation is cross group boundary + * and if the goal is inside the old reservation window, + * we will come here when we just failed to allocate from + * the first part of the window. We still have another part + * that belongs to the next group. In this case, there is no + * point to discard our window and try to allocate a new one + * in this group(which will fail). we should + * keep the reservation window, just simply move on. + * + * Maybe we could shift the start block of the reservation + * window to the first block of next group. + */ + + if ((my_rsv->rsv_start <= group_end_block) && + (my_rsv->rsv_end > group_end_block) && + (start_block >= my_rsv->rsv_start)) + return -1; + + if ((atomic_read(&my_rsv->rsv_alloc_hit) > + (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) { + /* + * if we previously allocation hit ration is greater than half + * we double the size of reservation window next time + * otherwise keep the same + */ + size = size * 2; + if (size > EXT3_MAX_RESERVE_BLOCKS) + size = EXT3_MAX_RESERVE_BLOCKS; + atomic_set(&my_rsv->rsv_goal_size, size); + } + } + /* + * shift the search start to the window near the goal block + */ + search_head = search_reserve_window(fs_rsv_root, start_block); + + /* + * find_next_reservable_window() simply finds a reservable window + * inside the given range(start_block, group_end_block). + * + * To make sure the reservation window has a free bit inside it, we + * need to check the bitmap after we found a reservable window. + */ +retry: + prev_rsv = find_next_reservable_window(search_head, size, + &start_block, group_end_block); + if (prev_rsv == NULL) + goto failed; + reservable_space_start = start_block; + /* + * On success, find_next_reservable_window() returns the + * reservation window where there is a reservable space after it. + * Before we reserve this reservable space, we need + * to make sure there is at least a free block inside this region. + * + * searching the first free bit on the block bitmap and copy of + * last committed bitmap alternatively, until we found a allocatable + * block. Search start from the start block of the reservable space + * we just found. + */ + first_free_block = bitmap_search_next_usable_block( + reservable_space_start - group_first_block, + bitmap_bh, group_end_block - group_first_block + 1); + + if (first_free_block < 0) { + /* + * no free block left on the bitmap, no point + * to reserve the space. return failed. + */ + goto failed; + } + start_block = first_free_block + group_first_block; + /* + * check if the first free block is within the + * free space we just found + */ + if ((start_block >= reservable_space_start) && + (start_block < reservable_space_start + size)) + goto found_rsv_window; + /* + * if the first free bit we found is out of the reservable space + * this means there is no free block on the reservable space + * we should continue search for next reservable space, + * start from where the free block is, + * we also shift the list head to where we stopped last time + */ + search_head = prev_rsv; + goto retry; + +found_rsv_window: + /* + * great! the reservable space contains some free blocks. + * if the search returns that we should add the new + * window just next to where the old window, we don't + * need to remove the old window first then add it to the + * same place, just update the new start and new end. + */ + if (my_rsv != prev_rsv) { + if (!rsv_is_empty(&my_rsv->rsv_window)) + rsv_window_remove(sb, my_rsv); + } + my_rsv->rsv_start = reservable_space_start; + my_rsv->rsv_end = my_rsv->rsv_start + size - 1; + atomic_set(&my_rsv->rsv_alloc_hit, 0); + if (my_rsv != prev_rsv) { + ext3_rsv_window_add(sb, my_rsv); + } + return 0; /* succeed */ +failed: + /* + * failed to find a new reservation window in the current + * group, remove the current(stale) reservation window + * if there is any + */ + if (!rsv_is_empty(&my_rsv->rsv_window)) + rsv_window_remove(sb, my_rsv); + return -1; /* failed */ +} + +/* + * This is the main function used to allocate a new block and its reservation + * window. + * + * Each time when a new block allocation is need, first try to allocate from + * its own reservation. If it does not have a reservation window, instead of + * looking for a free bit on bitmap first, then look up the reservation list to + * see if it is inside somebody else's reservation window, we try to allocate a + * reservation window for it starting from the goal first. Then do the block + * allocation within the reservation window. + * + * This will avoid keeping on searching the reservation list again and + * again when someboday is looking for a free block (without + * reservation), and there are lots of free blocks, but they are all + * being reserved. + * + * We use a sorted double linked list for the per-filesystem reservation list. + * The insert, remove and find a free space(non-reserved) operations for the + * sorted double linked list should be fast. + * + */ +static int +ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle, + unsigned int group, struct buffer_head *bitmap_bh, + int goal, struct ext3_reserve_window_node * my_rsv, + int *errp) +{ + spinlock_t *rsv_lock; + unsigned long group_first_block; + int ret = 0; + int fatal; + int credits = 0; + + *errp = 0; + + /* + * Make sure we use undo access for the bitmap, because it is critical + * that we do the frozen_data COW on bitmap buffers in all cases even + * if the buffer is in BJ_Forget state in the committing transaction. + */ + BUFFER_TRACE(bitmap_bh, "get undo access for new block"); + fatal = ext3_journal_get_undo_access(handle, bitmap_bh, &credits); if (fatal) { *errp = fatal; - goto fail; + return -1; + } + + /* + * we don't deal with reservation when + * filesystem is mounted without reservation + * or the file is not a regular file + * or last attempt to allocate a block with reservation turned on failed + */ + if (my_rsv == NULL ) { + ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal, NULL); + goto out; + } + rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock; + /* + * goal is a group relative block number (if there is a goal) + * 0 < goal < EXT3_BLOCKS_PER_GROUP(sb) + * first block is a filesystem wide block number + * first block is the block number of the first block in this group + */ + group_first_block = le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block) + + group * EXT3_BLOCKS_PER_GROUP(sb); + + /* + * Basically we will allocate a new block from inode's reservation + * window. + * + * We need to allocate a new reservation window, if: + * a) inode does not have a reservation window; or + * b) last attempt to allocate a block from existing reservation + * failed; or + * c) we come here with a goal and with a reservation window + * + * We do not need to allocate a new reservation window if we come here + * at the beginning with a goal and the goal is inside the window, or + * we don't have a goal but already have a reservation window. + * then we could go to allocate from the reservation window directly. + */ + while (1) { + struct ext3_reserve_window rsv_copy; + unsigned int seq; + + do { + seq = read_seqbegin(&my_rsv->rsv_seqlock); + rsv_copy._rsv_start = my_rsv->rsv_start; + rsv_copy._rsv_end = my_rsv->rsv_end; + } while (read_seqretry(&my_rsv->rsv_seqlock, seq)); + + if (rsv_is_empty(&rsv_copy) || (ret < 0) || + !goal_in_my_reservation(&rsv_copy, goal, group, sb)) { + spin_lock(rsv_lock); + write_seqlock(&my_rsv->rsv_seqlock); + ret = alloc_new_reservation(my_rsv, goal, sb, + group, bitmap_bh); + rsv_copy._rsv_start = my_rsv->rsv_start; + rsv_copy._rsv_end = my_rsv->rsv_end; + write_sequnlock(&my_rsv->rsv_seqlock); + spin_unlock(rsv_lock); + if (ret < 0) + break; /* failed */ + + if (!goal_in_my_reservation(&rsv_copy, goal, group, sb)) + goal = -1; + } + if ((rsv_copy._rsv_start >= group_first_block + EXT3_BLOCKS_PER_GROUP(sb)) + || (rsv_copy._rsv_end < group_first_block)) + BUG(); + ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh, goal, + &rsv_copy); + if (ret >= 0) { + if (!read_seqretry(&my_rsv->rsv_seqlock, seq)) + atomic_inc(&my_rsv->rsv_alloc_hit); + break; /* succeed */ + } + } +out: + if (ret >= 0) { + BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for " + "bitmap block"); + fatal = ext3_journal_dirty_metadata(handle, bitmap_bh); + if (fatal) { + *errp = fatal; + return -1; + } + return ret; } - return goal; -fail_access: BUFFER_TRACE(bitmap_bh, "journal_release_buffer"); ext3_journal_release_buffer(handle, bitmap_bh, credits); -fail: - return -1; + return ret; } static int ext3_has_free_blocks(struct super_block *sb) @@ -521,16 +1151,16 @@ int ext3_should_retry_alloc(struct super_block *sb, int *retries) * bitmap, and then for any free bit if that fails. * This function also updates quota and i_blocks field. */ -int -ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, - u32 *prealloc_count, u32 *prealloc_block, int *errp) +int ext3_new_block(handle_t *handle, struct inode *inode, + unsigned long goal, int *errp) { - struct buffer_head *bitmap_bh = NULL; /* bh */ - struct buffer_head *gdp_bh; /* bh2 */ - int group_no; /* i */ - int ret_block; /* j */ - int bgi; /* blockgroup iteration index */ - int target_block; /* tmp */ + struct buffer_head *bitmap_bh = NULL; + struct buffer_head *gdp_bh; + int group_no; + int goal_group; + int ret_block; + int bgi; /* blockgroup iteration index */ + int target_block; int fatal = 0, err; int performed_allocation = 0; int free_blocks; @@ -538,9 +1168,14 @@ ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, struct ext3_group_desc *gdp; struct ext3_super_block *es; struct ext3_sb_info *sbi; + struct ext3_reserve_window_node *my_rsv = NULL; + struct ext3_reserve_window_node *rsv = &EXT3_I(inode)->i_rsv_window; + unsigned short windowsz = 0; #ifdef EXT3FS_DEBUG static int goal_hits, goal_attempts; #endif + unsigned long ngroups; + *errp = -ENOSPC; sb = inode->i_sb; if (!sb) { @@ -561,7 +1196,18 @@ ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, sbi = EXT3_SB(sb); es = EXT3_SB(sb)->s_es; ext3_debug("goal=%lu.\n", goal); - + /* + * Allocate a block from reservation only when + * filesystem is mounted with reservation(default,-o reservation), and + * it's a regular file, and + * the desired window size is greater than 0 (One could use ioctl + * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off + * reservation on that particular file) + */ + windowsz = atomic_read(&rsv->rsv_goal_size); + if (test_opt(sb, RESERVATION) && + S_ISREG(inode->i_mode) && (windowsz > 0)) + my_rsv = rsv; if (!ext3_has_free_blocks(sb)) { *errp = -ENOSPC; goto out; @@ -579,6 +1225,8 @@ ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, if (!gdp) goto io_error; + goal_group = group_no; +retry: free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); if (free_blocks > 0) { ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) % @@ -586,21 +1234,24 @@ ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, bitmap_bh = read_block_bitmap(sb, group_no); if (!bitmap_bh) goto io_error; - ret_block = ext3_try_to_allocate(sb, handle, group_no, - bitmap_bh, ret_block, &fatal); + ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no, + bitmap_bh, ret_block, my_rsv, &fatal); if (fatal) goto out; if (ret_block >= 0) goto allocated; } + ngroups = EXT3_SB(sb)->s_groups_count; + smp_rmb(); + /* * Now search the rest of the groups. We assume that * i and gdp correctly point to the last group visited. */ - for (bgi = 0; bgi < EXT3_SB(sb)->s_groups_count; bgi++) { + for (bgi = 0; bgi < ngroups; bgi++) { group_no++; - if (group_no >= EXT3_SB(sb)->s_groups_count) + if (group_no >= ngroups) group_no = 0; gdp = ext3_get_group_desc(sb, group_no, &gdp_bh); if (!gdp) { @@ -608,21 +1259,37 @@ ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal, goto out; } free_blocks = le16_to_cpu(gdp->bg_free_blocks_count); - if (free_blocks <= 0) + /* + * skip this group if the number of + * free blocks is less than half of the reservation + * window size. + */ + if (free_blocks <= (windowsz/2)) continue; brelse(bitmap_bh); bitmap_bh = read_block_bitmap(sb, group_no); if (!bitmap_bh) goto io_error; - ret_block = ext3_try_to_allocate(sb, handle, group_no, - bitmap_bh, -1, &fatal); + ret_block = ext3_try_to_allocate_with_rsv(sb, handle, group_no, + bitmap_bh, -1, my_rsv, &fatal); if (fatal) goto out; if (ret_block >= 0) goto allocated; } - + /* + * We may end up a bogus ealier ENOSPC error due to + * filesystem is "full" of reservations, but + * there maybe indeed free blocks avaliable on disk + * In this case, we just forget about the reservations + * just do block allocation as without reservations. + */ + if (my_rsv) { + my_rsv = NULL; + group_no = goal_group; + goto retry; + } /* No space left on the device */ *errp = -ENOSPC; goto out; @@ -738,6 +1405,7 @@ unsigned long ext3_count_free_blocks(struct super_block *sb) unsigned long desc_count; struct ext3_group_desc *gdp; int i; + unsigned long ngroups; #ifdef EXT3FS_DEBUG struct ext3_super_block *es; unsigned long bitmap_count, x; @@ -770,7 +1438,9 @@ unsigned long ext3_count_free_blocks(struct super_block *sb) return bitmap_count; #else desc_count = 0; - for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) { + ngroups = EXT3_SB(sb)->s_groups_count; + smp_rmb(); + for (i = 0; i < ngroups; i++) { gdp = ext3_get_group_desc(sb, i, NULL); if (!gdp) continue; @@ -792,19 +1462,17 @@ static inline int block_in_use(unsigned long block, static inline int test_root(int a, int b) { - if (a == 0) - return 1; - while (1) { - if (a == 1) - return 1; - if (a % b) - return 0; - a = a / b; - } + int num = b; + + while (a > num) + num *= b; + return num == a; } -int ext3_group_sparse(int group) +static int ext3_group_sparse(int group) { + if (group <= 1) + return 1; return (test_root(group, 3) || test_root(group, 5) || test_root(group, 7)); }