diff options
Diffstat (limited to 'fs/reiserfs/bitmap.c')
| -rw-r--r-- | fs/reiserfs/bitmap.c | 237 |
1 files changed, 156 insertions, 81 deletions
diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c index c3de6501a5cb..70daba6fa6a5 100644 --- a/fs/reiserfs/bitmap.c +++ b/fs/reiserfs/bitmap.c @@ -50,8 +50,10 @@ static inline void get_bit_address(struct super_block *s, unsigned int *bmap_nr, unsigned int *offset) { - /* It is in the bitmap block number equal to the block - * number divided by the number of bits in a block. */ + /* + * It is in the bitmap block number equal to the block + * number divided by the number of bits in a block. + */ *bmap_nr = block >> (s->s_blocksize_bits + 3); /* Within that bitmap block it is located at bit offset *offset. */ *offset = block & ((s->s_blocksize << 3) - 1); @@ -71,8 +73,10 @@ int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value) get_bit_address(s, block, &bmap, &offset); - /* Old format filesystem? Unlikely, but the bitmaps are all up front so - * we need to account for it. */ + /* + * Old format filesystem? Unlikely, but the bitmaps are all + * up front so we need to account for it. + */ if (unlikely(test_bit(REISERFS_OLD_FORMAT, &(REISERFS_SB(s)->s_properties)))) { b_blocknr_t bmap1 = REISERFS_SB(s)->s_sbh->b_blocknr + 1; @@ -108,8 +112,11 @@ int is_reusable(struct super_block *s, b_blocknr_t block, int bit_value) return 1; } -/* searches in journal structures for a given block number (bmap, off). If block - is found in reiserfs journal it suggests next free block candidate to test. */ +/* + * Searches in journal structures for a given block number (bmap, off). + * If block is found in reiserfs journal it suggests next free block + * candidate to test. + */ static inline int is_block_in_journal(struct super_block *s, unsigned int bmap, int off, int *next) { @@ -120,7 +127,7 @@ static inline int is_block_in_journal(struct super_block *s, unsigned int bmap, *next = tmp; PROC_INFO_INC(s, scan_bitmap.in_journal_hint); } else { - (*next) = off + 1; /* inc offset to avoid looping. */ + (*next) = off + 1; /* inc offset to avoid looping. */ PROC_INFO_INC(s, scan_bitmap.in_journal_nohint); } PROC_INFO_INC(s, scan_bitmap.retry); @@ -129,8 +136,10 @@ static inline int is_block_in_journal(struct super_block *s, unsigned int bmap, return 0; } -/* it searches for a window of zero bits with given minimum and maximum lengths in one bitmap - * block; */ +/* + * Searches for a window of zero bits with given minimum and maximum + * lengths in one bitmap block + */ static int scan_bitmap_block(struct reiserfs_transaction_handle *th, unsigned int bmap_n, int *beg, int boundary, int min, int max, int unfm) @@ -146,10 +155,6 @@ static int scan_bitmap_block(struct reiserfs_transaction_handle *th, RFALSE(bmap_n >= reiserfs_bmap_count(s), "Bitmap %u is out of " "range (0..%u)", bmap_n, reiserfs_bmap_count(s) - 1); PROC_INFO_INC(s, scan_bitmap.bmap); -/* this is unclear and lacks comments, explain how journal bitmaps - work here for the reader. Convey a sense of the design here. What - is a window? */ -/* - I mean `a window of zero bits' as in description of this function - Zam. */ if (!bi) { reiserfs_error(s, "jdm-4055", "NULL bitmap info pointer " @@ -165,15 +170,18 @@ static int scan_bitmap_block(struct reiserfs_transaction_handle *th, cont: if (bi->free_count < min) { brelse(bh); - return 0; // No free blocks in this bitmap + return 0; /* No free blocks in this bitmap */ } /* search for a first zero bit -- beginning of a window */ *beg = reiserfs_find_next_zero_le_bit ((unsigned long *)(bh->b_data), boundary, *beg); - if (*beg + min > boundary) { /* search for a zero bit fails or the rest of bitmap block - * cannot contain a zero window of minimum size */ + /* + * search for a zero bit fails or the rest of bitmap block + * cannot contain a zero window of minimum size + */ + if (*beg + min > boundary) { brelse(bh); return 0; } @@ -187,37 +195,63 @@ static int scan_bitmap_block(struct reiserfs_transaction_handle *th, next = end; break; } - /* finding the other end of zero bit window requires looking into journal structures (in - * case of searching for free blocks for unformatted nodes) */ + + /* + * finding the other end of zero bit window requires + * looking into journal structures (in case of + * searching for free blocks for unformatted nodes) + */ if (unfm && is_block_in_journal(s, bmap_n, end, &next)) break; } - /* now (*beg) points to beginning of zero bits window, - * (end) points to one bit after the window end */ - if (end - *beg >= min) { /* it seems we have found window of proper size */ + /* + * now (*beg) points to beginning of zero bits window, + * (end) points to one bit after the window end + */ + + /* found window of proper size */ + if (end - *beg >= min) { int i; reiserfs_prepare_for_journal(s, bh, 1); - /* try to set all blocks used checking are they still free */ + /* + * try to set all blocks used checking are + * they still free + */ for (i = *beg; i < end; i++) { - /* It seems that we should not check in journal again. */ + /* Don't check in journal again. */ if (reiserfs_test_and_set_le_bit (i, bh->b_data)) { - /* bit was set by another process - * while we slept in prepare_for_journal() */ + /* + * bit was set by another process while + * we slept in prepare_for_journal() + */ PROC_INFO_INC(s, scan_bitmap.stolen); - if (i >= *beg + min) { /* we can continue with smaller set of allocated blocks, - * if length of this set is more or equal to `min' */ + + /* + * we can continue with smaller set + * of allocated blocks, if length of + * this set is more or equal to `min' + */ + if (i >= *beg + min) { end = i; break; } - /* otherwise we clear all bit were set ... */ + + /* + * otherwise we clear all bit + * were set ... + */ while (--i >= *beg) reiserfs_clear_le_bit (i, bh->b_data); reiserfs_restore_prepared_buffer(s, bh); *beg = org; - /* ... and search again in current block from beginning */ + + /* + * Search again in current block + * from beginning + */ goto cont; } } @@ -268,11 +302,13 @@ static inline int block_group_used(struct super_block *s, u32 id) int bm = bmap_hash_id(s, id); struct reiserfs_bitmap_info *info = &SB_AP_BITMAP(s)[bm]; - /* If we don't have cached information on this bitmap block, we're + /* + * If we don't have cached information on this bitmap block, we're * going to have to load it later anyway. Loading it here allows us * to make a better decision. This favors long-term performance gain * with a better on-disk layout vs. a short term gain of skipping the - * read and potentially having a bad placement. */ + * read and potentially having a bad placement. + */ if (info->free_count == UINT_MAX) { struct buffer_head *bh = reiserfs_read_bitmap_block(s, bm); brelse(bh); @@ -305,17 +341,16 @@ __le32 reiserfs_choose_packing(struct inode * dir) return packing; } -/* Tries to find contiguous zero bit window (given size) in given region of - * bitmap and place new blocks there. Returns number of allocated blocks. */ +/* + * Tries to find contiguous zero bit window (given size) in given region of + * bitmap and place new blocks there. Returns number of allocated blocks. + */ static int scan_bitmap(struct reiserfs_transaction_handle *th, b_blocknr_t * start, b_blocknr_t finish, int min, int max, int unfm, sector_t file_block) { int nr_allocated = 0; struct super_block *s = th->t_super; - /* find every bm and bmap and bmap_nr in this file, and change them all to bitmap_blocknr - * - Hans, it is not a block number - Zam. */ - unsigned int bm, off; unsigned int end_bm, end_off; unsigned int off_max = s->s_blocksize << 3; @@ -323,8 +358,10 @@ static int scan_bitmap(struct reiserfs_transaction_handle *th, BUG_ON(!th->t_trans_id); PROC_INFO_INC(s, scan_bitmap.call); + + /* No point in looking for more free blocks */ if (SB_FREE_BLOCKS(s) <= 0) - return 0; // No point in looking for more free blocks + return 0; get_bit_address(s, *start, &bm, &off); get_bit_address(s, finish, &end_bm, &end_off); @@ -333,7 +370,8 @@ static int scan_bitmap(struct reiserfs_transaction_handle *th, if (end_bm > reiserfs_bmap_count(s)) end_bm = reiserfs_bmap_count(s); - /* When the bitmap is more than 10% free, anyone can allocate. + /* + * When the bitmap is more than 10% free, anyone can allocate. * When it's less than 10% free, only files that already use the * bitmap are allowed. Once we pass 80% full, this restriction * is lifted. @@ -532,7 +570,8 @@ int reiserfs_parse_alloc_options(struct super_block *s, char *options) { char *this_char, *value; - REISERFS_SB(s)->s_alloc_options.bits = 0; /* clear default settings */ + /* clear default settings */ + REISERFS_SB(s)->s_alloc_options.bits = 0; while ((this_char = strsep(&options, ":")) != NULL) { if ((value = strchr(this_char, '=')) != NULL) @@ -733,7 +772,7 @@ static inline void new_hashed_relocation(reiserfs_blocknr_hint_t * hint) hash_in = (char *)&hint->key.k_dir_id; } else { if (!hint->inode) { - //hint->search_start = hint->beg; + /*hint->search_start = hint->beg;*/ hash_in = (char *)&hint->key.k_dir_id; } else if (TEST_OPTION(displace_based_on_dirid, hint->th->t_super)) @@ -786,7 +825,8 @@ static void oid_groups(reiserfs_blocknr_hint_t * hint) dirid = le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id); - /* keep the root dir and it's first set of subdirs close to + /* + * keep the root dir and it's first set of subdirs close to * the start of the disk */ if (dirid <= 2) @@ -800,7 +840,8 @@ static void oid_groups(reiserfs_blocknr_hint_t * hint) } } -/* returns 1 if it finds an indirect item and gets valid hint info +/* + * returns 1 if it finds an indirect item and gets valid hint info * from it, otherwise 0 */ static int get_left_neighbor(reiserfs_blocknr_hint_t * hint) @@ -812,8 +853,11 @@ static int get_left_neighbor(reiserfs_blocknr_hint_t * hint) __le32 *item; int ret = 0; - if (!hint->path) /* reiserfs code can call this function w/o pointer to path - * structure supplied; then we rely on supplied search_start */ + /* + * reiserfs code can call this function w/o pointer to path + * structure supplied; then we rely on supplied search_start + */ + if (!hint->path) return 0; path = hint->path; @@ -825,12 +869,13 @@ static int get_left_neighbor(reiserfs_blocknr_hint_t * hint) hint->search_start = bh->b_blocknr; + /* + * for indirect item: go to left and look for the first non-hole entry + * in the indirect item + */ if (!hint->formatted_node && is_indirect_le_ih(ih)) { - /* for indirect item: go to left and look for the first non-hole entry - in the indirect item */ if (pos_in_item == I_UNFM_NUM(ih)) pos_in_item--; -// pos_in_item = I_UNFM_NUM (ih) - 1; while (pos_in_item >= 0) { int t = get_block_num(item, pos_in_item); if (t) { @@ -846,10 +891,12 @@ static int get_left_neighbor(reiserfs_blocknr_hint_t * hint) return ret; } -/* should be, if formatted node, then try to put on first part of the device - specified as number of percent with mount option device, else try to put - on last of device. This is not to say it is good code to do so, - but the effect should be measured. */ +/* + * should be, if formatted node, then try to put on first part of the device + * specified as number of percent with mount option device, else try to put + * on last of device. This is not to say it is good code to do so, + * but the effect should be measured. + */ static inline void set_border_in_hint(struct super_block *s, reiserfs_blocknr_hint_t * hint) { @@ -975,21 +1022,27 @@ static void determine_search_start(reiserfs_blocknr_hint_t * hint, set_border_in_hint(s, hint); #ifdef DISPLACE_NEW_PACKING_LOCALITIES - /* whenever we create a new directory, we displace it. At first we will - hash for location, later we might look for a moderately empty place for - it */ + /* + * whenever we create a new directory, we displace it. At first + * we will hash for location, later we might look for a moderately + * empty place for it + */ if (displacing_new_packing_localities(s) && hint->th->displace_new_blocks) { displace_new_packing_locality(hint); - /* we do not continue determine_search_start, - * if new packing locality is being displaced */ + /* + * we do not continue determine_search_start, + * if new packing locality is being displaced + */ return; } #endif - /* all persons should feel encouraged to add more special cases here and - * test them */ + /* + * all persons should feel encouraged to add more special cases + * here and test them + */ if (displacing_large_files(s) && !hint->formatted_node && this_blocknr_allocation_would_make_it_a_large_file(hint)) { @@ -997,8 +1050,10 @@ static void determine_search_start(reiserfs_blocknr_hint_t * hint, return; } - /* if none of our special cases is relevant, use the left neighbor in the - tree order of the new node we are allocating for */ + /* + * if none of our special cases is relevant, use the left + * neighbor in the tree order of the new node we are allocating for + */ if (hint->formatted_node && TEST_OPTION(hashed_formatted_nodes, s)) { hash_formatted_node(hint); return; @@ -1006,10 +1061,13 @@ static void determine_search_start(reiserfs_blocknr_hint_t * hint, unfm_hint = get_left_neighbor(hint); - /* Mimic old block allocator behaviour, that is if VFS allowed for preallocation, - new blocks are displaced based on directory ID. Also, if suggested search_start - is less than last preallocated block, we start searching from it, assuming that - HDD dataflow is faster in forward direction */ + /* + * Mimic old block allocator behaviour, that is if VFS allowed for + * preallocation, new blocks are displaced based on directory ID. + * Also, if suggested search_start is less than last preallocated + * block, we start searching from it, assuming that HDD dataflow + * is faster in forward direction + */ if (TEST_OPTION(old_way, s)) { if (!hint->formatted_node) { if (!reiserfs_hashed_relocation(s)) @@ -1038,11 +1096,13 @@ static void determine_search_start(reiserfs_blocknr_hint_t * hint, TEST_OPTION(old_hashed_relocation, s)) { old_hashed_relocation(hint); } + /* new_hashed_relocation works with both formatted/unformatted nodes */ if ((!unfm_hint || hint->formatted_node) && TEST_OPTION(new_hashed_relocation, s)) { new_hashed_relocation(hint); } + /* dirid grouping works only on unformatted nodes */ if (!unfm_hint && !hint->formatted_node && TEST_OPTION(dirid_groups, s)) { dirid_groups(hint); @@ -1080,8 +1140,6 @@ static int determine_prealloc_size(reiserfs_blocknr_hint_t * hint) return CARRY_ON; } -/* XXX I know it could be merged with upper-level function; - but may be result function would be too complex. */ static inline int allocate_without_wrapping_disk(reiserfs_blocknr_hint_t * hint, b_blocknr_t * new_blocknrs, b_blocknr_t start, @@ -1109,7 +1167,10 @@ static inline int allocate_without_wrapping_disk(reiserfs_blocknr_hint_t * hint, /* do we have something to fill prealloc. array also ? */ if (nr_allocated > 0) { - /* it means prealloc_size was greater that 0 and we do preallocation */ + /* + * it means prealloc_size was greater that 0 and + * we do preallocation + */ list_add(&REISERFS_I(hint->inode)->i_prealloc_list, &SB_JOURNAL(hint->th->t_super)-> j_prealloc_list); @@ -1177,7 +1238,8 @@ static inline int blocknrs_and_prealloc_arrays_from_search_start start = 0; finish = hint->beg; break; - default: /* We've tried searching everywhere, not enough space */ + default: + /* We've tried searching everywhere, not enough space */ /* Free the blocks */ if (!hint->formatted_node) { #ifdef REISERQUOTA_DEBUG @@ -1262,8 +1324,11 @@ static int use_preallocated_list_if_available(reiserfs_blocknr_hint_t * hint, return amount_needed; } -int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t * hint, b_blocknr_t * new_blocknrs, int amount_needed, int reserved_by_us /* Amount of blocks we have - already reserved */ ) +int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t *hint, + b_blocknr_t *new_blocknrs, + int amount_needed, + /* Amount of blocks we have already reserved */ + int reserved_by_us) { int initial_amount_needed = amount_needed; int ret; @@ -1275,15 +1340,21 @@ int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t * hint, b_blocknr_t * new return NO_DISK_SPACE; /* should this be if !hint->inode && hint->preallocate? */ /* do you mean hint->formatted_node can be removed ? - Zam */ - /* hint->formatted_node cannot be removed because we try to access - inode information here, and there is often no inode assotiated with - metadata allocations - green */ + /* + * hint->formatted_node cannot be removed because we try to access + * inode information here, and there is often no inode associated with + * metadata allocations - green + */ if (!hint->formatted_node && hint->preallocate) { amount_needed = use_preallocated_list_if_available (hint, new_blocknrs, amount_needed); - if (amount_needed == 0) /* all blocknrs we need we got from - prealloc. list */ + + /* + * We have all the block numbers we need from the + * prealloc list + */ + if (amount_needed == 0) return CARRY_ON; new_blocknrs += (initial_amount_needed - amount_needed); } @@ -1297,10 +1368,12 @@ int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t * hint, b_blocknr_t * new ret = blocknrs_and_prealloc_arrays_from_search_start (hint, new_blocknrs, amount_needed); - /* we used prealloc. list to fill (partially) new_blocknrs array. If final allocation fails we - * need to return blocks back to prealloc. list or just free them. -- Zam (I chose second - * variant) */ - + /* + * We used prealloc. list to fill (partially) new_blocknrs array. + * If final allocation fails we need to return blocks back to + * prealloc. list or just free them. -- Zam (I chose second + * variant) + */ if (ret != CARRY_ON) { while (amount_needed++ < initial_amount_needed) { reiserfs_free_block(hint->th, hint->inode, @@ -1339,8 +1412,10 @@ struct buffer_head *reiserfs_read_bitmap_block(struct super_block *sb, struct reiserfs_bitmap_info *info = SB_AP_BITMAP(sb) + bitmap; struct buffer_head *bh; - /* Way old format filesystems had the bitmaps packed up front. - * I doubt there are any of these left, but just in case... */ + /* + * Way old format filesystems had the bitmaps packed up front. + * I doubt there are any of these left, but just in case... + */ if (unlikely(test_bit(REISERFS_OLD_FORMAT, &(REISERFS_SB(sb)->s_properties)))) block = REISERFS_SB(sb)->s_sbh->b_blocknr + 1 + bitmap; |