| /* |
| * linux/fs/ext3/balloc.c |
| * |
| * Copyright (C) 1992, 1993, 1994, 1995 |
| * Remy Card (card@masi.ibp.fr) |
| * Laboratoire MASI - Institut Blaise Pascal |
| * Universite Pierre et Marie Curie (Paris VI) |
| * |
| * Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993 |
| * Big-endian to little-endian byte-swapping/bitmaps by |
| * David S. Miller (davem@caip.rutgers.edu), 1995 |
| */ |
| |
| #include <linux/config.h> |
| #include <linux/time.h> |
| #include <linux/fs.h> |
| #include <linux/jbd.h> |
| #include <linux/ext3_fs.h> |
| #include <linux/ext3_jbd.h> |
| #include <linux/locks.h> |
| #include <linux/quotaops.h> |
| |
| /* |
| * balloc.c contains the blocks allocation and deallocation routines |
| */ |
| |
| /* |
| * The free blocks are managed by bitmaps. A file system contains several |
| * blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap |
| * block for inodes, N blocks for the inode table and data blocks. |
| * |
| * The file system contains group descriptors which are located after the |
| * super block. Each descriptor contains the number of the bitmap block and |
| * the free blocks count in the block. The descriptors are loaded in memory |
| * when a file system is mounted (see ext3_read_super). |
| */ |
| |
| |
| #define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1) |
| |
| struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb, |
| unsigned int block_group, |
| struct buffer_head ** bh) |
| { |
| unsigned long group_desc; |
| unsigned long desc; |
| struct ext3_group_desc * gdp; |
| |
| if (block_group >= sb->u.ext3_sb.s_groups_count) { |
| ext3_error (sb, "ext3_get_group_desc", |
| "block_group >= groups_count - " |
| "block_group = %d, groups_count = %lu", |
| block_group, sb->u.ext3_sb.s_groups_count); |
| |
| return NULL; |
| } |
| |
| group_desc = block_group / EXT3_DESC_PER_BLOCK(sb); |
| desc = block_group % EXT3_DESC_PER_BLOCK(sb); |
| if (!sb->u.ext3_sb.s_group_desc[group_desc]) { |
| ext3_error (sb, "ext3_get_group_desc", |
| "Group descriptor not loaded - " |
| "block_group = %d, group_desc = %lu, desc = %lu", |
| block_group, group_desc, desc); |
| return NULL; |
| } |
| |
| gdp = (struct ext3_group_desc *) |
| sb->u.ext3_sb.s_group_desc[group_desc]->b_data; |
| if (bh) |
| *bh = sb->u.ext3_sb.s_group_desc[group_desc]; |
| return gdp + desc; |
| } |
| |
| /* |
| * Read the bitmap for a given block_group, reading into the specified |
| * slot in the superblock's bitmap cache. |
| * |
| * Return >=0 on success or a -ve error code. |
| */ |
| |
| static int read_block_bitmap (struct super_block * sb, |
| unsigned int block_group, |
| unsigned long bitmap_nr) |
| { |
| struct ext3_group_desc * gdp; |
| struct buffer_head * bh = NULL; |
| int retval = -EIO; |
| |
| gdp = ext3_get_group_desc (sb, block_group, NULL); |
| if (!gdp) |
| goto error_out; |
| retval = 0; |
| bh = sb_bread(sb, le32_to_cpu(gdp->bg_block_bitmap)); |
| if (!bh) { |
| ext3_error (sb, "read_block_bitmap", |
| "Cannot read block bitmap - " |
| "block_group = %d, block_bitmap = %lu", |
| block_group, (unsigned long) gdp->bg_block_bitmap); |
| retval = -EIO; |
| } |
| /* |
| * On IO error, just leave a zero in the superblock's block pointer for |
| * this group. The IO will be retried next time. |
| */ |
| error_out: |
| sb->u.ext3_sb.s_block_bitmap_number[bitmap_nr] = block_group; |
| sb->u.ext3_sb.s_block_bitmap[bitmap_nr] = bh; |
| return retval; |
| } |
| |
| /* |
| * load_block_bitmap loads the block bitmap for a blocks group |
| * |
| * It maintains a cache for the last bitmaps loaded. This cache is managed |
| * with a LRU algorithm. |
| * |
| * Notes: |
| * 1/ There is one cache per mounted file system. |
| * 2/ If the file system contains less than EXT3_MAX_GROUP_LOADED groups, |
| * this function reads the bitmap without maintaining a LRU cache. |
| * |
| * Return the slot used to store the bitmap, or a -ve error code. |
| */ |
| static int __load_block_bitmap (struct super_block * sb, |
| unsigned int block_group) |
| { |
| int i, j, retval = 0; |
| unsigned long block_bitmap_number; |
| struct buffer_head * block_bitmap; |
| |
| if (block_group >= sb->u.ext3_sb.s_groups_count) |
| ext3_panic (sb, "load_block_bitmap", |
| "block_group >= groups_count - " |
| "block_group = %d, groups_count = %lu", |
| block_group, sb->u.ext3_sb.s_groups_count); |
| |
| if (sb->u.ext3_sb.s_groups_count <= EXT3_MAX_GROUP_LOADED) { |
| if (sb->u.ext3_sb.s_block_bitmap[block_group]) { |
| if (sb->u.ext3_sb.s_block_bitmap_number[block_group] == |
| block_group) |
| return block_group; |
| ext3_error (sb, "__load_block_bitmap", |
| "block_group != block_bitmap_number"); |
| } |
| retval = read_block_bitmap (sb, block_group, block_group); |
| if (retval < 0) |
| return retval; |
| return block_group; |
| } |
| |
| for (i = 0; i < sb->u.ext3_sb.s_loaded_block_bitmaps && |
| sb->u.ext3_sb.s_block_bitmap_number[i] != block_group; i++) |
| ; |
| if (i < sb->u.ext3_sb.s_loaded_block_bitmaps && |
| sb->u.ext3_sb.s_block_bitmap_number[i] == block_group) { |
| block_bitmap_number = sb->u.ext3_sb.s_block_bitmap_number[i]; |
| block_bitmap = sb->u.ext3_sb.s_block_bitmap[i]; |
| for (j = i; j > 0; j--) { |
| sb->u.ext3_sb.s_block_bitmap_number[j] = |
| sb->u.ext3_sb.s_block_bitmap_number[j - 1]; |
| sb->u.ext3_sb.s_block_bitmap[j] = |
| sb->u.ext3_sb.s_block_bitmap[j - 1]; |
| } |
| sb->u.ext3_sb.s_block_bitmap_number[0] = block_bitmap_number; |
| sb->u.ext3_sb.s_block_bitmap[0] = block_bitmap; |
| |
| /* |
| * There's still one special case here --- if block_bitmap == 0 |
| * then our last attempt to read the bitmap failed and we have |
| * just ended up caching that failure. Try again to read it. |
| */ |
| if (!block_bitmap) |
| retval = read_block_bitmap (sb, block_group, 0); |
| } else { |
| if (sb->u.ext3_sb.s_loaded_block_bitmaps<EXT3_MAX_GROUP_LOADED) |
| sb->u.ext3_sb.s_loaded_block_bitmaps++; |
| else |
| brelse (sb->u.ext3_sb.s_block_bitmap |
| [EXT3_MAX_GROUP_LOADED - 1]); |
| for (j = sb->u.ext3_sb.s_loaded_block_bitmaps - 1; |
| j > 0; j--) { |
| sb->u.ext3_sb.s_block_bitmap_number[j] = |
| sb->u.ext3_sb.s_block_bitmap_number[j - 1]; |
| sb->u.ext3_sb.s_block_bitmap[j] = |
| sb->u.ext3_sb.s_block_bitmap[j - 1]; |
| } |
| retval = read_block_bitmap (sb, block_group, 0); |
| } |
| return retval; |
| } |
| |
| /* |
| * Load the block bitmap for a given block group. First of all do a couple |
| * of fast lookups for common cases and then pass the request onto the guts |
| * of the bitmap loader. |
| * |
| * Return the slot number of the group in the superblock bitmap cache's on |
| * success, or a -ve error code. |
| * |
| * There is still one inconsistency here --- if the number of groups in this |
| * filesystems is <= EXT3_MAX_GROUP_LOADED, then we have no way of |
| * differentiating between a group for which we have never performed a bitmap |
| * IO request, and a group for which the last bitmap read request failed. |
| */ |
| static inline int load_block_bitmap (struct super_block * sb, |
| unsigned int block_group) |
| { |
| int slot; |
| |
| /* |
| * Do the lookup for the slot. First of all, check if we're asking |
| * for the same slot as last time, and did we succeed that last time? |
| */ |
| if (sb->u.ext3_sb.s_loaded_block_bitmaps > 0 && |
| sb->u.ext3_sb.s_block_bitmap_number[0] == block_group && |
| sb->u.ext3_sb.s_block_bitmap[0]) { |
| return 0; |
| } |
| /* |
| * Or can we do a fast lookup based on a loaded group on a filesystem |
| * small enough to be mapped directly into the superblock? |
| */ |
| else if (sb->u.ext3_sb.s_groups_count <= EXT3_MAX_GROUP_LOADED && |
| sb->u.ext3_sb.s_block_bitmap_number[block_group]==block_group |
| && sb->u.ext3_sb.s_block_bitmap[block_group]) { |
| slot = block_group; |
| } |
| /* |
| * If not, then do a full lookup for this block group. |
| */ |
| else { |
| slot = __load_block_bitmap (sb, block_group); |
| } |
| |
| /* |
| * <0 means we just got an error |
| */ |
| if (slot < 0) |
| return slot; |
| |
| /* |
| * If it's a valid slot, we may still have cached a previous IO error, |
| * in which case the bh in the superblock cache will be zero. |
| */ |
| if (!sb->u.ext3_sb.s_block_bitmap[slot]) |
| return -EIO; |
| |
| /* |
| * Must have been read in OK to get this far. |
| */ |
| return slot; |
| } |
| |
| /* 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 buffer_head *bitmap_bh; |
| struct buffer_head *gd_bh; |
| unsigned long block_group; |
| unsigned long bit; |
| unsigned long i; |
| int bitmap_nr; |
| unsigned long overflow; |
| struct super_block * sb; |
| struct ext3_group_desc * gdp; |
| struct ext3_super_block * es; |
| int err = 0, ret; |
| int dquot_freed_blocks = 0; |
| |
| sb = inode->i_sb; |
| if (!sb) { |
| printk ("ext3_free_blocks: nonexistent device"); |
| return; |
| } |
| lock_super (sb); |
| es = sb->u.ext3_sb.s_es; |
| if (block < le32_to_cpu(es->s_first_data_block) || |
| (block + count) > le32_to_cpu(es->s_blocks_count)) { |
| ext3_error (sb, "ext3_free_blocks", |
| "Freeing blocks not in datazone - " |
| "block = %lu, count = %lu", block, count); |
| goto error_return; |
| } |
| |
| ext3_debug ("freeing block %lu\n", block); |
| |
| do_more: |
| overflow = 0; |
| block_group = (block - le32_to_cpu(es->s_first_data_block)) / |
| EXT3_BLOCKS_PER_GROUP(sb); |
| bit = (block - le32_to_cpu(es->s_first_data_block)) % |
| EXT3_BLOCKS_PER_GROUP(sb); |
| /* |
| * Check to see if we are freeing blocks across a group |
| * boundary. |
| */ |
| if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) { |
| overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb); |
| count -= overflow; |
| } |
| bitmap_nr = load_block_bitmap (sb, block_group); |
| if (bitmap_nr < 0) |
| goto error_return; |
| |
| bitmap_bh = sb->u.ext3_sb.s_block_bitmap[bitmap_nr]; |
| gdp = ext3_get_group_desc (sb, block_group, &gd_bh); |
| if (!gdp) |
| goto error_return; |
| |
| if (in_range (le32_to_cpu(gdp->bg_block_bitmap), block, count) || |
| in_range (le32_to_cpu(gdp->bg_inode_bitmap), block, count) || |
| in_range (block, le32_to_cpu(gdp->bg_inode_table), |
| sb->u.ext3_sb.s_itb_per_group) || |
| in_range (block + count - 1, le32_to_cpu(gdp->bg_inode_table), |
| sb->u.ext3_sb.s_itb_per_group)) |
| ext3_error (sb, "ext3_free_blocks", |
| "Freeing blocks in system zones - " |
| "Block = %lu, count = %lu", |
| block, count); |
| |
| /* |
| * We are about to start releasing blocks in the bitmap, |
| * so we need undo access. |
| */ |
| /* @@@ check errors */ |
| BUFFER_TRACE(bitmap_bh, "getting undo access"); |
| err = ext3_journal_get_undo_access(handle, bitmap_bh); |
| if (err) |
| goto error_return; |
| |
| /* |
| * We are about to modify some metadata. Call the journal APIs |
| * to unshare ->b_data if a currently-committing transaction is |
| * using it |
| */ |
| BUFFER_TRACE(gd_bh, "get_write_access"); |
| err = ext3_journal_get_write_access(handle, gd_bh); |
| if (err) |
| goto error_return; |
| |
| BUFFER_TRACE(sb->u.ext3_sb.s_sbh, "get_write_access"); |
| err = ext3_journal_get_write_access(handle, sb->u.ext3_sb.s_sbh); |
| if (err) |
| goto error_return; |
| |
| for (i = 0; i < count; i++) { |
| /* |
| * An HJ special. This is expensive... |
| */ |
| #ifdef CONFIG_JBD_DEBUG |
| { |
| struct buffer_head *debug_bh; |
| debug_bh = sb_get_hash_table(sb, block + i); |
| if (debug_bh) { |
| BUFFER_TRACE(debug_bh, "Deleted!"); |
| if (!bh2jh(bitmap_bh)->b_committed_data) |
| BUFFER_TRACE(debug_bh, |
| "No commited data in bitmap"); |
| BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap"); |
| __brelse(debug_bh); |
| } |
| } |
| #endif |
| BUFFER_TRACE(bitmap_bh, "clear bit"); |
| if (!ext3_clear_bit (bit + i, bitmap_bh->b_data)) { |
| ext3_error (sb, __FUNCTION__, |
| "bit already cleared for block %lu", |
| block + i); |
| BUFFER_TRACE(bitmap_bh, "bit already cleared"); |
| } else { |
| dquot_freed_blocks++; |
| gdp->bg_free_blocks_count = |
| cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)+1); |
| es->s_free_blocks_count = |
| cpu_to_le32(le32_to_cpu(es->s_free_blocks_count)+1); |
| } |
| /* @@@ This prevents newly-allocated data from being |
| * freed and then reallocated within the same |
| * transaction. |
| * |
| * Ideally we would want to allow that to happen, but to |
| * do so requires making journal_forget() capable of |
| * revoking the queued write of a data block, which |
| * implies blocking on the journal lock. *forget() |
| * cannot block due to truncate races. |
| * |
| * Eventually we can fix this by making journal_forget() |
| * return a status indicating whether or not it was able |
| * to revoke the buffer. On successful revoke, it is |
| * safe not to set the allocation bit in the committed |
| * bitmap, because we know that there is no outstanding |
| * activity on the buffer any more and so it is safe to |
| * reallocate it. |
| */ |
| BUFFER_TRACE(bitmap_bh, "clear in b_committed_data"); |
| J_ASSERT_BH(bitmap_bh, |
| bh2jh(bitmap_bh)->b_committed_data != NULL); |
| ext3_set_bit(bit + i, bh2jh(bitmap_bh)->b_committed_data); |
| } |
| |
| /* We dirtied the bitmap block */ |
| BUFFER_TRACE(bitmap_bh, "dirtied bitmap block"); |
| err = ext3_journal_dirty_metadata(handle, bitmap_bh); |
| |
| /* And the group descriptor block */ |
| BUFFER_TRACE(gd_bh, "dirtied group descriptor block"); |
| ret = ext3_journal_dirty_metadata(handle, gd_bh); |
| if (!err) err = ret; |
| |
| /* And the superblock */ |
| BUFFER_TRACE(sb->u.ext3_sb.s_sbh, "dirtied superblock"); |
| ret = ext3_journal_dirty_metadata(handle, sb->u.ext3_sb.s_sbh); |
| if (!err) err = ret; |
| |
| if (overflow && !err) { |
| block += count; |
| count = overflow; |
| goto do_more; |
| } |
| sb->s_dirt = 1; |
| error_return: |
| ext3_std_error(sb, err); |
| unlock_super(sb); |
| if (dquot_freed_blocks) |
| DQUOT_FREE_BLOCK(inode, dquot_freed_blocks); |
| return; |
| } |
| |
| /* For ext3 allocations, we must not reuse any blocks which are |
| * allocated in the bitmap buffer's "last committed data" copy. This |
| * prevents deletes from freeing up the page for reuse until we have |
| * committed the delete transaction. |
| * |
| * If we didn't do this, then deleting something and reallocating it as |
| * data would allow the old block to be overwritten before the |
| * transaction committed (because we force data to disk before commit). |
| * This would lead to corruption if we crashed between overwriting the |
| * data and committing the delete. |
| * |
| * @@@ We may want to make this allocation behaviour conditional on |
| * data-writes at some point, and disable it for metadata allocations or |
| * sync-data inodes. |
| */ |
| static int ext3_test_allocatable(int nr, struct buffer_head *bh) |
| { |
| if (ext3_test_bit(nr, bh->b_data)) |
| return 0; |
| if (!buffer_jbd(bh) || !bh2jh(bh)->b_committed_data) |
| return 1; |
| return !ext3_test_bit(nr, bh2jh(bh)->b_committed_data); |
| } |
| |
| /* |
| * Find an allocatable block in a bitmap. We honour both the bitmap and |
| * its last-committed copy (if that exists), and perform the "most |
| * appropriate allocation" algorithm of looking for a free block near |
| * the initial goal; then for a free byte somewhere in the bitmap; then |
| * for any free bit in the bitmap. |
| */ |
| static int find_next_usable_block(int start, |
| struct buffer_head *bh, int maxblocks) |
| { |
| int here, next; |
| char *p, *r; |
| |
| if (start > 0) { |
| /* |
| * The goal was occupied; search forward for a free |
| * block within the next XX blocks. |
| * |
| * end_goal is more or less random, but it has to be |
| * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the |
| * next 64-bit boundary is simple.. |
| */ |
| int end_goal = (start + 63) & ~63; |
| here = ext3_find_next_zero_bit(bh->b_data, end_goal, start); |
| if (here < end_goal && ext3_test_allocatable(here, bh)) |
| return here; |
| |
| ext3_debug ("Bit not found near goal\n"); |
| |
| } |
| |
| here = start; |
| if (here < 0) |
| here = 0; |
| |
| /* |
| * There has been no free block found in the near vicinity of |
| * the goal: do a search forward through the block groups, |
| * searching in each group first for an entire free byte in the |
| * bitmap and then for any free bit. |
| * |
| * Search first in the remainder of the current group |
| */ |
| p = ((char *) bh->b_data) + (here >> 3); |
| r = memscan(p, 0, (maxblocks - here + 7) >> 3); |
| next = (r - ((char *) bh->b_data)) << 3; |
| |
| if (next < maxblocks && ext3_test_allocatable(next, bh)) |
| return next; |
| |
| /* The bitmap search --- search forward alternately |
| * through the actual bitmap and the last-committed copy |
| * until we find a bit free in both. */ |
| |
| while (here < maxblocks) { |
| next = ext3_find_next_zero_bit ((unsigned long *) bh->b_data, |
| maxblocks, here); |
| if (next >= maxblocks) |
| return -1; |
| if (ext3_test_allocatable(next, bh)) |
| return next; |
| |
| J_ASSERT_BH(bh, bh2jh(bh)->b_committed_data); |
| here = ext3_find_next_zero_bit |
| ((unsigned long *) bh2jh(bh)->b_committed_data, |
| maxblocks, next); |
| } |
| return -1; |
| } |
| |
| /* |
| * ext3_new_block uses a goal block to assist allocation. If the goal is |
| * free, or there is a free block within 32 blocks of the goal, that block |
| * is allocated. Otherwise a forward search is made for a free block; within |
| * each block group the search first looks for an entire free byte in the block |
| * 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) |
| { |
| struct buffer_head * bh, *bhtmp; |
| struct buffer_head * bh2; |
| #if 0 |
| char * p, * r; |
| #endif |
| int i, j, k, tmp, alloctmp; |
| int bitmap_nr; |
| int fatal = 0, err; |
| struct super_block * sb; |
| struct ext3_group_desc * gdp; |
| struct ext3_super_block * es; |
| #ifdef EXT3FS_DEBUG |
| static int goal_hits = 0, goal_attempts = 0; |
| #endif |
| *errp = -ENOSPC; |
| sb = inode->i_sb; |
| if (!sb) { |
| printk ("ext3_new_block: nonexistent device"); |
| return 0; |
| } |
| |
| /* |
| * Check quota for allocation of this block. |
| */ |
| if (DQUOT_ALLOC_BLOCK(inode, 1)) { |
| *errp = -EDQUOT; |
| return 0; |
| } |
| |
| lock_super (sb); |
| es = sb->u.ext3_sb.s_es; |
| if (le32_to_cpu(es->s_free_blocks_count) <= |
| le32_to_cpu(es->s_r_blocks_count) && |
| ((sb->u.ext3_sb.s_resuid != current->fsuid) && |
| (sb->u.ext3_sb.s_resgid == 0 || |
| !in_group_p (sb->u.ext3_sb.s_resgid)) && |
| !capable(CAP_SYS_RESOURCE))) |
| goto out; |
| |
| ext3_debug ("goal=%lu.\n", goal); |
| |
| /* |
| * First, test whether the goal block is free. |
| */ |
| if (goal < le32_to_cpu(es->s_first_data_block) || |
| goal >= le32_to_cpu(es->s_blocks_count)) |
| goal = le32_to_cpu(es->s_first_data_block); |
| i = (goal - le32_to_cpu(es->s_first_data_block)) / |
| EXT3_BLOCKS_PER_GROUP(sb); |
| gdp = ext3_get_group_desc (sb, i, &bh2); |
| if (!gdp) |
| goto io_error; |
| |
| if (le16_to_cpu(gdp->bg_free_blocks_count) > 0) { |
| j = ((goal - le32_to_cpu(es->s_first_data_block)) % |
| EXT3_BLOCKS_PER_GROUP(sb)); |
| #ifdef EXT3FS_DEBUG |
| if (j) |
| goal_attempts++; |
| #endif |
| bitmap_nr = load_block_bitmap (sb, i); |
| if (bitmap_nr < 0) |
| goto io_error; |
| |
| bh = sb->u.ext3_sb.s_block_bitmap[bitmap_nr]; |
| |
| ext3_debug ("goal is at %d:%d.\n", i, j); |
| |
| if (ext3_test_allocatable(j, bh)) { |
| #ifdef EXT3FS_DEBUG |
| goal_hits++; |
| ext3_debug ("goal bit allocated.\n"); |
| #endif |
| goto got_block; |
| } |
| |
| j = find_next_usable_block(j, bh, EXT3_BLOCKS_PER_GROUP(sb)); |
| if (j >= 0) |
| goto search_back; |
| } |
| |
| ext3_debug ("Bit not found in block group %d.\n", i); |
| |
| /* |
| * Now search the rest of the groups. We assume that |
| * i and gdp correctly point to the last group visited. |
| */ |
| for (k = 0; k < sb->u.ext3_sb.s_groups_count; k++) { |
| i++; |
| if (i >= sb->u.ext3_sb.s_groups_count) |
| i = 0; |
| gdp = ext3_get_group_desc (sb, i, &bh2); |
| if (!gdp) { |
| *errp = -EIO; |
| goto out; |
| } |
| if (le16_to_cpu(gdp->bg_free_blocks_count) > 0) { |
| bitmap_nr = load_block_bitmap (sb, i); |
| if (bitmap_nr < 0) |
| goto io_error; |
| |
| bh = sb->u.ext3_sb.s_block_bitmap[bitmap_nr]; |
| j = find_next_usable_block(-1, bh, |
| EXT3_BLOCKS_PER_GROUP(sb)); |
| if (j >= 0) |
| goto search_back; |
| } |
| } |
| |
| /* No space left on the device */ |
| unlock_super (sb); |
| return 0; |
| |
| search_back: |
| /* |
| * We have succeeded in finding a free byte in the block |
| * bitmap. Now search backwards up to 7 bits to find the |
| * start of this group of free blocks. |
| */ |
| for ( k = 0; |
| k < 7 && j > 0 && ext3_test_allocatable(j - 1, bh); |
| k++, j--) |
| ; |
| |
| got_block: |
| |
| ext3_debug ("using block group %d(%d)\n", i, gdp->bg_free_blocks_count); |
| |
| /* 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(bh, "get undo access for marking new block"); |
| fatal = ext3_journal_get_undo_access(handle, bh); |
| if (fatal) goto out; |
| |
| BUFFER_TRACE(bh2, "get_write_access"); |
| fatal = ext3_journal_get_write_access(handle, bh2); |
| if (fatal) goto out; |
| |
| BUFFER_TRACE(sb->u.ext3_sb.s_sbh, "get_write_access"); |
| fatal = ext3_journal_get_write_access(handle, sb->u.ext3_sb.s_sbh); |
| if (fatal) goto out; |
| |
| tmp = j + i * EXT3_BLOCKS_PER_GROUP(sb) |
| + le32_to_cpu(es->s_first_data_block); |
| |
| if (tmp == le32_to_cpu(gdp->bg_block_bitmap) || |
| tmp == le32_to_cpu(gdp->bg_inode_bitmap) || |
| in_range (tmp, le32_to_cpu(gdp->bg_inode_table), |
| sb->u.ext3_sb.s_itb_per_group)) |
| ext3_error (sb, "ext3_new_block", |
| "Allocating block in system zone - " |
| "block = %u", tmp); |
| |
| /* The superblock lock should guard against anybody else beating |
| * us to this point! */ |
| J_ASSERT_BH(bh, !ext3_test_bit(j, bh->b_data)); |
| BUFFER_TRACE(bh, "setting bitmap bit"); |
| ext3_set_bit(j, bh->b_data); |
| |
| #ifdef CONFIG_JBD_DEBUG |
| { |
| struct buffer_head *debug_bh; |
| |
| /* Record bitmap buffer state in the newly allocated block */ |
| debug_bh = sb_get_hash_table(sb, tmp); |
| if (debug_bh) { |
| BUFFER_TRACE(debug_bh, "state when allocated"); |
| BUFFER_TRACE2(debug_bh, bh, "bitmap state"); |
| brelse(debug_bh); |
| } |
| } |
| #endif |
| if (buffer_jbd(bh) && bh2jh(bh)->b_committed_data) |
| J_ASSERT_BH(bh, !ext3_test_bit(j, bh2jh(bh)->b_committed_data)); |
| bhtmp = bh; |
| alloctmp = j; |
| |
| ext3_debug ("found bit %d\n", j); |
| |
| /* |
| * Do block preallocation now if required. |
| */ |
| #ifdef EXT3_PREALLOCATE |
| /* |
| * akpm: this is not enabled for ext3. Need to use |
| * ext3_test_allocatable() |
| */ |
| /* Writer: ->i_prealloc* */ |
| if (prealloc_count && !*prealloc_count) { |
| int prealloc_goal; |
| unsigned long next_block = tmp + 1; |
| |
| prealloc_goal = es->s_prealloc_blocks ? |
| es->s_prealloc_blocks : EXT3_DEFAULT_PREALLOC_BLOCKS; |
| |
| *prealloc_block = next_block; |
| /* Writer: end */ |
| for (k = 1; |
| k < prealloc_goal && (j + k) < EXT3_BLOCKS_PER_GROUP(sb); |
| k++, next_block++) { |
| if (DQUOT_PREALLOC_BLOCK(inode, 1)) |
| break; |
| /* Writer: ->i_prealloc* */ |
| if (*prealloc_block + *prealloc_count != next_block || |
| ext3_set_bit (j + k, bh->b_data)) { |
| /* Writer: end */ |
| DQUOT_FREE_BLOCK(inode, 1); |
| break; |
| } |
| (*prealloc_count)++; |
| /* Writer: end */ |
| } |
| /* |
| * As soon as we go for per-group spinlocks we'll need these |
| * done inside the loop above. |
| */ |
| gdp->bg_free_blocks_count = |
| cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - |
| (k - 1)); |
| es->s_free_blocks_count = |
| cpu_to_le32(le32_to_cpu(es->s_free_blocks_count) - |
| (k - 1)); |
| ext3_debug ("Preallocated a further %lu bits.\n", |
| (k - 1)); |
| } |
| #endif |
| |
| j = tmp; |
| |
| BUFFER_TRACE(bh, "journal_dirty_metadata for bitmap block"); |
| err = ext3_journal_dirty_metadata(handle, bh); |
| if (!fatal) fatal = err; |
| |
| if (j >= le32_to_cpu(es->s_blocks_count)) { |
| ext3_error (sb, "ext3_new_block", |
| "block(%d) >= blocks count(%d) - " |
| "block_group = %d, es == %p ",j, |
| le32_to_cpu(es->s_blocks_count), i, es); |
| goto out; |
| } |
| |
| /* |
| * It is up to the caller to add the new buffer to a journal |
| * list of some description. We don't know in advance whether |
| * the caller wants to use it as metadata or data. |
| */ |
| |
| ext3_debug ("allocating block %d. " |
| "Goal hits %d of %d.\n", j, goal_hits, goal_attempts); |
| |
| gdp->bg_free_blocks_count = |
| cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - 1); |
| es->s_free_blocks_count = |
| cpu_to_le32(le32_to_cpu(es->s_free_blocks_count) - 1); |
| |
| BUFFER_TRACE(bh2, "journal_dirty_metadata for group descriptor"); |
| err = ext3_journal_dirty_metadata(handle, bh2); |
| if (!fatal) fatal = err; |
| |
| BUFFER_TRACE(bh, "journal_dirty_metadata for superblock"); |
| err = ext3_journal_dirty_metadata(handle, sb->u.ext3_sb.s_sbh); |
| if (!fatal) fatal = err; |
| |
| sb->s_dirt = 1; |
| if (fatal) |
| goto out; |
| |
| unlock_super (sb); |
| *errp = 0; |
| return j; |
| |
| io_error: |
| *errp = -EIO; |
| out: |
| if (fatal) { |
| *errp = fatal; |
| ext3_std_error(sb, fatal); |
| } |
| unlock_super (sb); |
| return 0; |
| |
| } |
| |
| unsigned long ext3_count_free_blocks (struct super_block * sb) |
| { |
| #ifdef EXT3FS_DEBUG |
| struct ext3_super_block * es; |
| unsigned long desc_count, bitmap_count, x; |
| int bitmap_nr; |
| struct ext3_group_desc * gdp; |
| int i; |
| |
| lock_super (sb); |
| es = sb->u.ext3_sb.s_es; |
| desc_count = 0; |
| bitmap_count = 0; |
| gdp = NULL; |
| for (i = 0; i < sb->u.ext3_sb.s_groups_count; i++) { |
| gdp = ext3_get_group_desc (sb, i, NULL); |
| if (!gdp) |
| continue; |
| desc_count += le16_to_cpu(gdp->bg_free_blocks_count); |
| bitmap_nr = load_block_bitmap (sb, i); |
| if (bitmap_nr < 0) |
| continue; |
| |
| x = ext3_count_free (sb->u.ext3_sb.s_block_bitmap[bitmap_nr], |
| sb->s_blocksize); |
| printk ("group %d: stored = %d, counted = %lu\n", |
| i, le16_to_cpu(gdp->bg_free_blocks_count), x); |
| bitmap_count += x; |
| } |
| printk("ext3_count_free_blocks: stored = %lu, computed = %lu, %lu\n", |
| le32_to_cpu(es->s_free_blocks_count), desc_count, bitmap_count); |
| unlock_super (sb); |
| return bitmap_count; |
| #else |
| return le32_to_cpu(sb->u.ext3_sb.s_es->s_free_blocks_count); |
| #endif |
| } |
| |
| static inline int block_in_use (unsigned long block, |
| struct super_block * sb, |
| unsigned char * map) |
| { |
| return ext3_test_bit ((block - |
| le32_to_cpu(sb->u.ext3_sb.s_es->s_first_data_block)) % |
| EXT3_BLOCKS_PER_GROUP(sb), map); |
| } |
| |
| 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 ext3_group_sparse(int group) |
| { |
| return (test_root(group, 3) || test_root(group, 5) || |
| test_root(group, 7)); |
| } |
| |
| /** |
| * ext3_bg_has_super - number of blocks used by the superblock in group |
| * @sb: superblock for filesystem |
| * @group: group number to check |
| * |
| * Return the number of blocks used by the superblock (primary or backup) |
| * in this group. Currently this will be only 0 or 1. |
| */ |
| int ext3_bg_has_super(struct super_block *sb, int group) |
| { |
| if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&& |
| !ext3_group_sparse(group)) |
| return 0; |
| return 1; |
| } |
| |
| /** |
| * ext3_bg_num_gdb - number of blocks used by the group table in group |
| * @sb: superblock for filesystem |
| * @group: group number to check |
| * |
| * Return the number of blocks used by the group descriptor table |
| * (primary or backup) in this group. In the future there may be a |
| * different number of descriptor blocks in each group. |
| */ |
| unsigned long ext3_bg_num_gdb(struct super_block *sb, int group) |
| { |
| if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&& |
| !ext3_group_sparse(group)) |
| return 0; |
| return EXT3_SB(sb)->s_gdb_count; |
| } |
| |
| #ifdef CONFIG_EXT3_CHECK |
| /* Called at mount-time, super-block is locked */ |
| void ext3_check_blocks_bitmap (struct super_block * sb) |
| { |
| struct buffer_head * bh; |
| struct ext3_super_block * es; |
| unsigned long desc_count, bitmap_count, x, j; |
| unsigned long desc_blocks; |
| int bitmap_nr; |
| struct ext3_group_desc * gdp; |
| int i; |
| |
| es = sb->u.ext3_sb.s_es; |
| desc_count = 0; |
| bitmap_count = 0; |
| gdp = NULL; |
| for (i = 0; i < sb->u.ext3_sb.s_groups_count; i++) { |
| gdp = ext3_get_group_desc (sb, i, NULL); |
| if (!gdp) |
| continue; |
| desc_count += le16_to_cpu(gdp->bg_free_blocks_count); |
| bitmap_nr = load_block_bitmap (sb, i); |
| if (bitmap_nr < 0) |
| continue; |
| |
| bh = EXT3_SB(sb)->s_block_bitmap[bitmap_nr]; |
| |
| if (ext3_bg_has_super(sb, i) && !ext3_test_bit(0, bh->b_data)) |
| ext3_error(sb, __FUNCTION__, |
| "Superblock in group %d is marked free", i); |
| |
| desc_blocks = ext3_bg_num_gdb(sb, i); |
| for (j = 0; j < desc_blocks; j++) |
| if (!ext3_test_bit(j + 1, bh->b_data)) |
| ext3_error(sb, __FUNCTION__, |
| "Descriptor block #%ld in group " |
| "%d is marked free", j, i); |
| |
| if (!block_in_use (le32_to_cpu(gdp->bg_block_bitmap), |
| sb, bh->b_data)) |
| ext3_error (sb, "ext3_check_blocks_bitmap", |
| "Block bitmap for group %d is marked free", |
| i); |
| |
| if (!block_in_use (le32_to_cpu(gdp->bg_inode_bitmap), |
| sb, bh->b_data)) |
| ext3_error (sb, "ext3_check_blocks_bitmap", |
| "Inode bitmap for group %d is marked free", |
| i); |
| |
| for (j = 0; j < sb->u.ext3_sb.s_itb_per_group; j++) |
| if (!block_in_use (le32_to_cpu(gdp->bg_inode_table) + j, |
| sb, bh->b_data)) |
| ext3_error (sb, "ext3_check_blocks_bitmap", |
| "Block #%d of the inode table in " |
| "group %d is marked free", j, i); |
| |
| x = ext3_count_free (bh, sb->s_blocksize); |
| if (le16_to_cpu(gdp->bg_free_blocks_count) != x) |
| ext3_error (sb, "ext3_check_blocks_bitmap", |
| "Wrong free blocks count for group %d, " |
| "stored = %d, counted = %lu", i, |
| le16_to_cpu(gdp->bg_free_blocks_count), x); |
| bitmap_count += x; |
| } |
| if (le32_to_cpu(es->s_free_blocks_count) != bitmap_count) |
| ext3_error (sb, "ext3_check_blocks_bitmap", |
| "Wrong free blocks count in super block, " |
| "stored = %lu, counted = %lu", |
| (unsigned long)le32_to_cpu(es->s_free_blocks_count), |
| bitmap_count); |
| } |
| #endif |