/* * 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 #include #include #include #include #include #include #include /* * 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_bitmapsu.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