diff options
Diffstat (limited to 'ANDROID_3.4.5/fs/ext4/balloc.c')
| -rw-r--r-- | ANDROID_3.4.5/fs/ext4/balloc.c | 766 |
1 files changed, 0 insertions, 766 deletions
diff --git a/ANDROID_3.4.5/fs/ext4/balloc.c b/ANDROID_3.4.5/fs/ext4/balloc.c deleted file mode 100644 index 8da837be..00000000 --- a/ANDROID_3.4.5/fs/ext4/balloc.c +++ /dev/null @@ -1,766 +0,0 @@ -/* - * linux/fs/ext4/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/time.h> -#include <linux/capability.h> -#include <linux/fs.h> -#include <linux/jbd2.h> -#include <linux/quotaops.h> -#include <linux/buffer_head.h> -#include "ext4.h" -#include "ext4_jbd2.h" -#include "mballoc.h" - -#include <trace/events/ext4.h> - -static unsigned ext4_num_base_meta_clusters(struct super_block *sb, - ext4_group_t block_group); -/* - * balloc.c contains the blocks allocation and deallocation routines - */ - -/* - * Calculate the block group number and offset into the block/cluster - * allocation bitmap, given a block number - */ -void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr, - ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp) -{ - struct ext4_super_block *es = EXT4_SB(sb)->s_es; - ext4_grpblk_t offset; - - blocknr = blocknr - le32_to_cpu(es->s_first_data_block); - offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb)) >> - EXT4_SB(sb)->s_cluster_bits; - if (offsetp) - *offsetp = offset; - if (blockgrpp) - *blockgrpp = blocknr; - -} - -static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block, - ext4_group_t block_group) -{ - ext4_group_t actual_group; - ext4_get_group_no_and_offset(sb, block, &actual_group, NULL); - if (actual_group == block_group) - return 1; - return 0; -} - -/* Return the number of clusters used for file system metadata; this - * represents the overhead needed by the file system. - */ -unsigned ext4_num_overhead_clusters(struct super_block *sb, - ext4_group_t block_group, - struct ext4_group_desc *gdp) -{ - unsigned num_clusters; - int block_cluster = -1, inode_cluster = -1, itbl_cluster = -1, i, c; - ext4_fsblk_t start = ext4_group_first_block_no(sb, block_group); - ext4_fsblk_t itbl_blk; - struct ext4_sb_info *sbi = EXT4_SB(sb); - - /* This is the number of clusters used by the superblock, - * block group descriptors, and reserved block group - * descriptor blocks */ - num_clusters = ext4_num_base_meta_clusters(sb, block_group); - - /* - * For the allocation bitmaps and inode table, we first need - * to check to see if the block is in the block group. If it - * is, then check to see if the cluster is already accounted - * for in the clusters used for the base metadata cluster, or - * if we can increment the base metadata cluster to include - * that block. Otherwise, we will have to track the cluster - * used for the allocation bitmap or inode table explicitly. - * Normally all of these blocks are contiguous, so the special - * case handling shouldn't be necessary except for *very* - * unusual file system layouts. - */ - if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) { - block_cluster = EXT4_B2C(sbi, - ext4_block_bitmap(sb, gdp) - start); - if (block_cluster < num_clusters) - block_cluster = -1; - else if (block_cluster == num_clusters) { - num_clusters++; - block_cluster = -1; - } - } - - if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) { - inode_cluster = EXT4_B2C(sbi, - ext4_inode_bitmap(sb, gdp) - start); - if (inode_cluster < num_clusters) - inode_cluster = -1; - else if (inode_cluster == num_clusters) { - num_clusters++; - inode_cluster = -1; - } - } - - itbl_blk = ext4_inode_table(sb, gdp); - for (i = 0; i < sbi->s_itb_per_group; i++) { - if (ext4_block_in_group(sb, itbl_blk + i, block_group)) { - c = EXT4_B2C(sbi, itbl_blk + i - start); - if ((c < num_clusters) || (c == inode_cluster) || - (c == block_cluster) || (c == itbl_cluster)) - continue; - if (c == num_clusters) { - num_clusters++; - continue; - } - num_clusters++; - itbl_cluster = c; - } - } - - if (block_cluster != -1) - num_clusters++; - if (inode_cluster != -1) - num_clusters++; - - return num_clusters; -} - -static unsigned int num_clusters_in_group(struct super_block *sb, - ext4_group_t block_group) -{ - unsigned int blocks; - - if (block_group == ext4_get_groups_count(sb) - 1) { - /* - * Even though mke2fs always initializes the first and - * last group, just in case some other tool was used, - * we need to make sure we calculate the right free - * blocks. - */ - blocks = ext4_blocks_count(EXT4_SB(sb)->s_es) - - ext4_group_first_block_no(sb, block_group); - } else - blocks = EXT4_BLOCKS_PER_GROUP(sb); - return EXT4_NUM_B2C(EXT4_SB(sb), blocks); -} - -/* Initializes an uninitialized block bitmap */ -void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh, - ext4_group_t block_group, - struct ext4_group_desc *gdp) -{ - unsigned int bit, bit_max; - struct ext4_sb_info *sbi = EXT4_SB(sb); - ext4_fsblk_t start, tmp; - int flex_bg = 0; - - J_ASSERT_BH(bh, buffer_locked(bh)); - - /* If checksum is bad mark all blocks used to prevent allocation - * essentially implementing a per-group read-only flag. */ - if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) { - ext4_error(sb, "Checksum bad for group %u", block_group); - ext4_free_group_clusters_set(sb, gdp, 0); - ext4_free_inodes_set(sb, gdp, 0); - ext4_itable_unused_set(sb, gdp, 0); - memset(bh->b_data, 0xff, sb->s_blocksize); - return; - } - memset(bh->b_data, 0, sb->s_blocksize); - - bit_max = ext4_num_base_meta_clusters(sb, block_group); - for (bit = 0; bit < bit_max; bit++) - ext4_set_bit(bit, bh->b_data); - - start = ext4_group_first_block_no(sb, block_group); - - if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) - flex_bg = 1; - - /* Set bits for block and inode bitmaps, and inode table */ - tmp = ext4_block_bitmap(sb, gdp); - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); - - tmp = ext4_inode_bitmap(sb, gdp); - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); - - tmp = ext4_inode_table(sb, gdp); - for (; tmp < ext4_inode_table(sb, gdp) + - sbi->s_itb_per_group; tmp++) { - if (!flex_bg || ext4_block_in_group(sb, tmp, block_group)) - ext4_set_bit(EXT4_B2C(sbi, tmp - start), bh->b_data); - } - - /* - * Also if the number of blocks within the group is less than - * the blocksize * 8 ( which is the size of bitmap ), set rest - * of the block bitmap to 1 - */ - ext4_mark_bitmap_end(num_clusters_in_group(sb, block_group), - sb->s_blocksize * 8, bh->b_data); -} - -/* Return the number of free blocks in a block group. It is used when - * the block bitmap is uninitialized, so we can't just count the bits - * in the bitmap. */ -unsigned ext4_free_clusters_after_init(struct super_block *sb, - ext4_group_t block_group, - struct ext4_group_desc *gdp) -{ - return num_clusters_in_group(sb, block_group) - - ext4_num_overhead_clusters(sb, block_group, gdp); -} - -/* - * 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 ext4_fill_super). - */ - -/** - * ext4_get_group_desc() -- load group descriptor from disk - * @sb: super block - * @block_group: given block group - * @bh: pointer to the buffer head to store the block - * group descriptor - */ -struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb, - ext4_group_t block_group, - struct buffer_head **bh) -{ - unsigned int group_desc; - unsigned int offset; - ext4_group_t ngroups = ext4_get_groups_count(sb); - struct ext4_group_desc *desc; - struct ext4_sb_info *sbi = EXT4_SB(sb); - - if (block_group >= ngroups) { - ext4_error(sb, "block_group >= groups_count - block_group = %u," - " groups_count = %u", block_group, ngroups); - - return NULL; - } - - group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb); - offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1); - if (!sbi->s_group_desc[group_desc]) { - ext4_error(sb, "Group descriptor not loaded - " - "block_group = %u, group_desc = %u, desc = %u", - block_group, group_desc, offset); - return NULL; - } - - desc = (struct ext4_group_desc *)( - (__u8 *)sbi->s_group_desc[group_desc]->b_data + - offset * EXT4_DESC_SIZE(sb)); - if (bh) - *bh = sbi->s_group_desc[group_desc]; - return desc; -} - -static int ext4_valid_block_bitmap(struct super_block *sb, - struct ext4_group_desc *desc, - unsigned int block_group, - struct buffer_head *bh) -{ - ext4_grpblk_t offset; - ext4_grpblk_t next_zero_bit; - ext4_fsblk_t bitmap_blk; - ext4_fsblk_t group_first_block; - - if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) { - /* with FLEX_BG, the inode/block bitmaps and itable - * blocks may not be in the group at all - * so the bitmap validation will be skipped for those groups - * or it has to also read the block group where the bitmaps - * are located to verify they are set. - */ - return 1; - } - group_first_block = ext4_group_first_block_no(sb, block_group); - - /* check whether block bitmap block number is set */ - bitmap_blk = ext4_block_bitmap(sb, desc); - offset = bitmap_blk - group_first_block; - if (!ext4_test_bit(offset, bh->b_data)) - /* bad block bitmap */ - goto err_out; - - /* check whether the inode bitmap block number is set */ - bitmap_blk = ext4_inode_bitmap(sb, desc); - offset = bitmap_blk - group_first_block; - if (!ext4_test_bit(offset, bh->b_data)) - /* bad block bitmap */ - goto err_out; - - /* check whether the inode table block number is set */ - bitmap_blk = ext4_inode_table(sb, desc); - offset = bitmap_blk - group_first_block; - next_zero_bit = ext4_find_next_zero_bit(bh->b_data, - offset + EXT4_SB(sb)->s_itb_per_group, - offset); - if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group) - /* good bitmap for inode tables */ - return 1; - -err_out: - ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu", - block_group, bitmap_blk); - return 0; -} -/** - * ext4_read_block_bitmap() - * @sb: super block - * @block_group: given block group - * - * Read the bitmap for a given block_group,and validate the - * bits for block/inode/inode tables are set in the bitmaps - * - * Return buffer_head on success or NULL in case of failure. - */ -struct buffer_head * -ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) -{ - struct ext4_group_desc *desc; - struct buffer_head *bh; - ext4_fsblk_t bitmap_blk; - - desc = ext4_get_group_desc(sb, block_group, NULL); - if (!desc) - return NULL; - bitmap_blk = ext4_block_bitmap(sb, desc); - bh = sb_getblk(sb, bitmap_blk); - if (unlikely(!bh)) { - ext4_error(sb, "Cannot get buffer for block bitmap - " - "block_group = %u, block_bitmap = %llu", - block_group, bitmap_blk); - return NULL; - } - - if (bitmap_uptodate(bh)) - return bh; - - lock_buffer(bh); - if (bitmap_uptodate(bh)) { - unlock_buffer(bh); - return bh; - } - ext4_lock_group(sb, block_group); - if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) { - ext4_init_block_bitmap(sb, bh, block_group, desc); - set_bitmap_uptodate(bh); - set_buffer_uptodate(bh); - ext4_unlock_group(sb, block_group); - unlock_buffer(bh); - return bh; - } - ext4_unlock_group(sb, block_group); - if (buffer_uptodate(bh)) { - /* - * if not uninit if bh is uptodate, - * bitmap is also uptodate - */ - set_bitmap_uptodate(bh); - unlock_buffer(bh); - return bh; - } - /* - * submit the buffer_head for reading - */ - set_buffer_new(bh); - trace_ext4_read_block_bitmap_load(sb, block_group); - bh->b_end_io = ext4_end_bitmap_read; - get_bh(bh); - submit_bh(READ, bh); - return bh; -} - -/* Returns 0 on success, 1 on error */ -int ext4_wait_block_bitmap(struct super_block *sb, ext4_group_t block_group, - struct buffer_head *bh) -{ - struct ext4_group_desc *desc; - - if (!buffer_new(bh)) - return 0; - desc = ext4_get_group_desc(sb, block_group, NULL); - if (!desc) - return 1; - wait_on_buffer(bh); - if (!buffer_uptodate(bh)) { - ext4_error(sb, "Cannot read block bitmap - " - "block_group = %u, block_bitmap = %llu", - block_group, (unsigned long long) bh->b_blocknr); - return 1; - } - clear_buffer_new(bh); - /* Panic or remount fs read-only if block bitmap is invalid */ - ext4_valid_block_bitmap(sb, desc, block_group, bh); - return 0; -} - -struct buffer_head * -ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group) -{ - struct buffer_head *bh; - - bh = ext4_read_block_bitmap_nowait(sb, block_group); - if (ext4_wait_block_bitmap(sb, block_group, bh)) { - put_bh(bh); - return NULL; - } - return bh; -} - -/** - * ext4_has_free_clusters() - * @sbi: in-core super block structure. - * @nclusters: number of needed blocks - * @flags: flags from ext4_mb_new_blocks() - * - * Check if filesystem has nclusters free & available for allocation. - * On success return 1, return 0 on failure. - */ -static int ext4_has_free_clusters(struct ext4_sb_info *sbi, - s64 nclusters, unsigned int flags) -{ - s64 free_clusters, dirty_clusters, root_clusters; - struct percpu_counter *fcc = &sbi->s_freeclusters_counter; - struct percpu_counter *dcc = &sbi->s_dirtyclusters_counter; - - free_clusters = percpu_counter_read_positive(fcc); - dirty_clusters = percpu_counter_read_positive(dcc); - root_clusters = EXT4_B2C(sbi, ext4_r_blocks_count(sbi->s_es)); - - if (free_clusters - (nclusters + root_clusters + dirty_clusters) < - EXT4_FREECLUSTERS_WATERMARK) { - free_clusters = EXT4_C2B(sbi, percpu_counter_sum_positive(fcc)); - dirty_clusters = percpu_counter_sum_positive(dcc); - } - /* Check whether we have space after accounting for current - * dirty clusters & root reserved clusters. - */ - if (free_clusters >= ((root_clusters + nclusters) + dirty_clusters)) - return 1; - - /* Hm, nope. Are (enough) root reserved clusters available? */ - if (sbi->s_resuid == current_fsuid() || - ((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) || - capable(CAP_SYS_RESOURCE) || - (flags & EXT4_MB_USE_ROOT_BLOCKS)) { - - if (free_clusters >= (nclusters + dirty_clusters)) - return 1; - } - - return 0; -} - -int ext4_claim_free_clusters(struct ext4_sb_info *sbi, - s64 nclusters, unsigned int flags) -{ - if (ext4_has_free_clusters(sbi, nclusters, flags)) { - percpu_counter_add(&sbi->s_dirtyclusters_counter, nclusters); - return 0; - } else - return -ENOSPC; -} - -/** - * ext4_should_retry_alloc() - * @sb: super block - * @retries number of attemps has been made - * - * ext4_should_retry_alloc() is called when ENOSPC is returned, and if - * it is profitable to retry the operation, this function will wait - * for the current or committing transaction to complete, and then - * return TRUE. - * - * if the total number of retries exceed three times, return FALSE. - */ -int ext4_should_retry_alloc(struct super_block *sb, int *retries) -{ - if (!ext4_has_free_clusters(EXT4_SB(sb), 1, 0) || - (*retries)++ > 3 || - !EXT4_SB(sb)->s_journal) - return 0; - - jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id); - - return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal); -} - -/* - * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks - * - * @handle: handle to this transaction - * @inode: file inode - * @goal: given target block(filesystem wide) - * @count: pointer to total number of clusters needed - * @errp: error code - * - * Return 1st allocated block number on success, *count stores total account - * error stores in errp pointer - */ -ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode, - ext4_fsblk_t goal, unsigned int flags, - unsigned long *count, int *errp) -{ - struct ext4_allocation_request ar; - ext4_fsblk_t ret; - - memset(&ar, 0, sizeof(ar)); - /* Fill with neighbour allocated blocks */ - ar.inode = inode; - ar.goal = goal; - ar.len = count ? *count : 1; - ar.flags = flags; - - ret = ext4_mb_new_blocks(handle, &ar, errp); - if (count) - *count = ar.len; - /* - * Account for the allocated meta blocks. We will never - * fail EDQUOT for metdata, but we do account for it. - */ - if (!(*errp) && - ext4_test_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED)) { - spin_lock(&EXT4_I(inode)->i_block_reservation_lock); - EXT4_I(inode)->i_allocated_meta_blocks += ar.len; - spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); - dquot_alloc_block_nofail(inode, - EXT4_C2B(EXT4_SB(inode->i_sb), ar.len)); - } - return ret; -} - -/** - * ext4_count_free_clusters() -- count filesystem free clusters - * @sb: superblock - * - * Adds up the number of free clusters from each block group. - */ -ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) -{ - ext4_fsblk_t desc_count; - struct ext4_group_desc *gdp; - ext4_group_t i; - ext4_group_t ngroups = ext4_get_groups_count(sb); -#ifdef EXT4FS_DEBUG - struct ext4_super_block *es; - ext4_fsblk_t bitmap_count; - unsigned int x; - struct buffer_head *bitmap_bh = NULL; - - es = EXT4_SB(sb)->s_es; - desc_count = 0; - bitmap_count = 0; - gdp = NULL; - - for (i = 0; i < ngroups; i++) { - gdp = ext4_get_group_desc(sb, i, NULL); - if (!gdp) - continue; - desc_count += ext4_free_group_clusters(sb, gdp); - brelse(bitmap_bh); - bitmap_bh = ext4_read_block_bitmap(sb, i); - if (bitmap_bh == NULL) - continue; - - x = ext4_count_free(bitmap_bh, sb->s_blocksize); - printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", - i, ext4_free_group_clusters(sb, gdp), x); - bitmap_count += x; - } - brelse(bitmap_bh); - printk(KERN_DEBUG "ext4_count_free_clusters: stored = %llu" - ", computed = %llu, %llu\n", - EXT4_B2C(EXT4_SB(sb), ext4_free_blocks_count(es)), - desc_count, bitmap_count); - return bitmap_count; -#else - desc_count = 0; - for (i = 0; i < ngroups; i++) { - gdp = ext4_get_group_desc(sb, i, NULL); - if (!gdp) - continue; - desc_count += ext4_free_group_clusters(sb, gdp); - } - - return desc_count; -#endif -} - -static inline int test_root(ext4_group_t a, int b) -{ - int num = b; - - while (a > num) - num *= b; - return num == a; -} - -static int ext4_group_sparse(ext4_group_t group) -{ - if (group <= 1) - return 1; - if (!(group & 1)) - return 0; - return (test_root(group, 7) || test_root(group, 5) || - test_root(group, 3)); -} - -/** - * ext4_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 ext4_bg_has_super(struct super_block *sb, ext4_group_t group) -{ - if (EXT4_HAS_RO_COMPAT_FEATURE(sb, - EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) && - !ext4_group_sparse(group)) - return 0; - return 1; -} - -static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb, - ext4_group_t group) -{ - unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); - ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb); - ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1; - - if (group == first || group == first + 1 || group == last) - return 1; - return 0; -} - -static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb, - ext4_group_t group) -{ - if (!ext4_bg_has_super(sb, group)) - return 0; - - if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG)) - return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); - else - return EXT4_SB(sb)->s_gdb_count; -} - -/** - * ext4_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 ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group) -{ - unsigned long first_meta_bg = - le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg); - unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb); - - if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) || - metagroup < first_meta_bg) - return ext4_bg_num_gdb_nometa(sb, group); - - return ext4_bg_num_gdb_meta(sb,group); - -} - -/* - * This function returns the number of file system metadata clusters at - * the beginning of a block group, including the reserved gdt blocks. - */ -static unsigned ext4_num_base_meta_clusters(struct super_block *sb, - ext4_group_t block_group) -{ - struct ext4_sb_info *sbi = EXT4_SB(sb); - unsigned num; - - /* Check for superblock and gdt backups in this group */ - num = ext4_bg_has_super(sb, block_group); - - if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) || - block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) * - sbi->s_desc_per_block) { - if (num) { - num += ext4_bg_num_gdb(sb, block_group); - num += le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks); - } - } else { /* For META_BG_BLOCK_GROUPS */ - num += ext4_bg_num_gdb(sb, block_group); - } - return EXT4_NUM_B2C(sbi, num); -} -/** - * ext4_inode_to_goal_block - return a hint for block allocation - * @inode: inode for block allocation - * - * Return the ideal location to start allocating blocks for a - * newly created inode. - */ -ext4_fsblk_t ext4_inode_to_goal_block(struct inode *inode) -{ - struct ext4_inode_info *ei = EXT4_I(inode); - ext4_group_t block_group; - ext4_grpblk_t colour; - int flex_size = ext4_flex_bg_size(EXT4_SB(inode->i_sb)); - ext4_fsblk_t bg_start; - ext4_fsblk_t last_block; - - block_group = ei->i_block_group; - if (flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) { - /* - * If there are at least EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME - * block groups per flexgroup, reserve the first block - * group for directories and special files. Regular - * files will start at the second block group. This - * tends to speed up directory access and improves - * fsck times. - */ - block_group &= ~(flex_size-1); - if (S_ISREG(inode->i_mode)) - block_group++; - } - bg_start = ext4_group_first_block_no(inode->i_sb, block_group); - last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; - - /* - * If we are doing delayed allocation, we don't need take - * colour into account. - */ - if (test_opt(inode->i_sb, DELALLOC)) - return bg_start; - - if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) - colour = (current->pid % 16) * - (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); - else - colour = (current->pid % 16) * ((last_block - bg_start) / 16); - return bg_start + colour; -} - |