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- /*
- * linux/fs/ext2/ialloc.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)
- *
- * BSD ufs-inspired inode and directory allocation by
- * Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
- * Big-endian to little-endian byte-swapping/bitmaps by
- * David S. Miller (davem@caip.rutgers.edu), 1995
- */
- #include <linux/quotaops.h>
- #include <linux/sched.h>
- #include <linux/backing-dev.h>
- #include <linux/buffer_head.h>
- #include <linux/random.h>
- #include "ext2.h"
- #include "xattr.h"
- #include "acl.h"
- /*
- * ialloc.c contains the inodes allocation and deallocation routines
- */
- /*
- * The free inodes 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.
- */
- /*
- * Read the inode allocation bitmap for a given block_group, reading
- * into the specified slot in the superblock's bitmap cache.
- *
- * Return buffer_head of bitmap on success or NULL.
- */
- static struct buffer_head *
- read_inode_bitmap(struct super_block * sb, unsigned long block_group)
- {
- struct ext2_group_desc *desc;
- struct buffer_head *bh = NULL;
- desc = ext2_get_group_desc(sb, block_group, NULL);
- if (!desc)
- goto error_out;
- bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
- if (!bh)
- ext2_error(sb, "read_inode_bitmap",
- "Cannot read inode bitmap - "
- "block_group = %lu, inode_bitmap = %u",
- block_group, le32_to_cpu(desc->bg_inode_bitmap));
- error_out:
- return bh;
- }
- static void ext2_release_inode(struct super_block *sb, int group, int dir)
- {
- struct ext2_group_desc * desc;
- struct buffer_head *bh;
- desc = ext2_get_group_desc(sb, group, &bh);
- if (!desc) {
- ext2_error(sb, "ext2_release_inode",
- "can't get descriptor for group %d", group);
- return;
- }
- spin_lock(sb_bgl_lock(EXT2_SB(sb), group));
- le16_add_cpu(&desc->bg_free_inodes_count, 1);
- if (dir)
- le16_add_cpu(&desc->bg_used_dirs_count, -1);
- spin_unlock(sb_bgl_lock(EXT2_SB(sb), group));
- if (dir)
- percpu_counter_dec(&EXT2_SB(sb)->s_dirs_counter);
- mark_buffer_dirty(bh);
- }
- /*
- * NOTE! When we get the inode, we're the only people
- * that have access to it, and as such there are no
- * race conditions we have to worry about. The inode
- * is not on the hash-lists, and it cannot be reached
- * through the filesystem because the directory entry
- * has been deleted earlier.
- *
- * HOWEVER: we must make sure that we get no aliases,
- * which means that we have to call "clear_inode()"
- * _before_ we mark the inode not in use in the inode
- * bitmaps. Otherwise a newly created file might use
- * the same inode number (not actually the same pointer
- * though), and then we'd have two inodes sharing the
- * same inode number and space on the harddisk.
- */
- void ext2_free_inode (struct inode * inode)
- {
- struct super_block * sb = inode->i_sb;
- int is_directory;
- unsigned long ino;
- struct buffer_head *bitmap_bh;
- unsigned long block_group;
- unsigned long bit;
- struct ext2_super_block * es;
- ino = inode->i_ino;
- ext2_debug ("freeing inode %lu\n", ino);
- /*
- * Note: we must free any quota before locking the superblock,
- * as writing the quota to disk may need the lock as well.
- */
- /* Quota is already initialized in iput() */
- dquot_free_inode(inode);
- dquot_drop(inode);
- es = EXT2_SB(sb)->s_es;
- is_directory = S_ISDIR(inode->i_mode);
- if (ino < EXT2_FIRST_INO(sb) ||
- ino > le32_to_cpu(es->s_inodes_count)) {
- ext2_error (sb, "ext2_free_inode",
- "reserved or nonexistent inode %lu", ino);
- return;
- }
- block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
- bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
- bitmap_bh = read_inode_bitmap(sb, block_group);
- if (!bitmap_bh)
- return;
- /* Ok, now we can actually update the inode bitmaps.. */
- if (!ext2_clear_bit_atomic(sb_bgl_lock(EXT2_SB(sb), block_group),
- bit, (void *) bitmap_bh->b_data))
- ext2_error (sb, "ext2_free_inode",
- "bit already cleared for inode %lu", ino);
- else
- ext2_release_inode(sb, block_group, is_directory);
- mark_buffer_dirty(bitmap_bh);
- if (sb->s_flags & MS_SYNCHRONOUS)
- sync_dirty_buffer(bitmap_bh);
- brelse(bitmap_bh);
- }
- /*
- * We perform asynchronous prereading of the new inode's inode block when
- * we create the inode, in the expectation that the inode will be written
- * back soon. There are two reasons:
- *
- * - When creating a large number of files, the async prereads will be
- * nicely merged into large reads
- * - When writing out a large number of inodes, we don't need to keep on
- * stalling the writes while we read the inode block.
- *
- * FIXME: ext2_get_group_desc() needs to be simplified.
- */
- static void ext2_preread_inode(struct inode *inode)
- {
- unsigned long block_group;
- unsigned long offset;
- unsigned long block;
- struct ext2_group_desc * gdp;
- struct backing_dev_info *bdi;
- bdi = inode_to_bdi(inode);
- if (bdi_read_congested(bdi))
- return;
- if (bdi_write_congested(bdi))
- return;
- block_group = (inode->i_ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
- gdp = ext2_get_group_desc(inode->i_sb, block_group, NULL);
- if (gdp == NULL)
- return;
- /*
- * Figure out the offset within the block group inode table
- */
- offset = ((inode->i_ino - 1) % EXT2_INODES_PER_GROUP(inode->i_sb)) *
- EXT2_INODE_SIZE(inode->i_sb);
- block = le32_to_cpu(gdp->bg_inode_table) +
- (offset >> EXT2_BLOCK_SIZE_BITS(inode->i_sb));
- sb_breadahead(inode->i_sb, block);
- }
- /*
- * There are two policies for allocating an inode. If the new inode is
- * a directory, then a forward search is made for a block group with both
- * free space and a low directory-to-inode ratio; if that fails, then of
- * the groups with above-average free space, that group with the fewest
- * directories already is chosen.
- *
- * For other inodes, search forward from the parent directory\'s block
- * group to find a free inode.
- */
- static int find_group_dir(struct super_block *sb, struct inode *parent)
- {
- int ngroups = EXT2_SB(sb)->s_groups_count;
- int avefreei = ext2_count_free_inodes(sb) / ngroups;
- struct ext2_group_desc *desc, *best_desc = NULL;
- int group, best_group = -1;
- for (group = 0; group < ngroups; group++) {
- desc = ext2_get_group_desc (sb, group, NULL);
- if (!desc || !desc->bg_free_inodes_count)
- continue;
- if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
- continue;
- if (!best_desc ||
- (le16_to_cpu(desc->bg_free_blocks_count) >
- le16_to_cpu(best_desc->bg_free_blocks_count))) {
- best_group = group;
- best_desc = desc;
- }
- }
- if (!best_desc)
- return -1;
- return best_group;
- }
- /*
- * Orlov's allocator for directories.
- *
- * We always try to spread first-level directories.
- *
- * If there are blockgroups with both free inodes and free blocks counts
- * not worse than average we return one with smallest directory count.
- * Otherwise we simply return a random group.
- *
- * For the rest rules look so:
- *
- * It's OK to put directory into a group unless
- * it has too many directories already (max_dirs) or
- * it has too few free inodes left (min_inodes) or
- * it has too few free blocks left (min_blocks) or
- * it's already running too large debt (max_debt).
- * Parent's group is preferred, if it doesn't satisfy these
- * conditions we search cyclically through the rest. If none
- * of the groups look good we just look for a group with more
- * free inodes than average (starting at parent's group).
- *
- * Debt is incremented each time we allocate a directory and decremented
- * when we allocate an inode, within 0--255.
- */
- #define INODE_COST 64
- #define BLOCK_COST 256
- static int find_group_orlov(struct super_block *sb, struct inode *parent)
- {
- int parent_group = EXT2_I(parent)->i_block_group;
- struct ext2_sb_info *sbi = EXT2_SB(sb);
- struct ext2_super_block *es = sbi->s_es;
- int ngroups = sbi->s_groups_count;
- int inodes_per_group = EXT2_INODES_PER_GROUP(sb);
- int freei;
- int avefreei;
- int free_blocks;
- int avefreeb;
- int blocks_per_dir;
- int ndirs;
- int max_debt, max_dirs, min_blocks, min_inodes;
- int group = -1, i;
- struct ext2_group_desc *desc;
- freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
- avefreei = freei / ngroups;
- free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
- avefreeb = free_blocks / ngroups;
- ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
- if ((parent == d_inode(sb->s_root)) ||
- (EXT2_I(parent)->i_flags & EXT2_TOPDIR_FL)) {
- struct ext2_group_desc *best_desc = NULL;
- int best_ndir = inodes_per_group;
- int best_group = -1;
- group = prandom_u32();
- parent_group = (unsigned)group % ngroups;
- for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (!desc || !desc->bg_free_inodes_count)
- continue;
- if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
- continue;
- if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
- continue;
- if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
- continue;
- best_group = group;
- best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
- best_desc = desc;
- }
- if (best_group >= 0) {
- desc = best_desc;
- group = best_group;
- goto found;
- }
- goto fallback;
- }
- if (ndirs == 0)
- ndirs = 1; /* percpu_counters are approximate... */
- blocks_per_dir = (le32_to_cpu(es->s_blocks_count)-free_blocks) / ndirs;
- max_dirs = ndirs / ngroups + inodes_per_group / 16;
- min_inodes = avefreei - inodes_per_group / 4;
- min_blocks = avefreeb - EXT2_BLOCKS_PER_GROUP(sb) / 4;
- max_debt = EXT2_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, BLOCK_COST);
- if (max_debt * INODE_COST > inodes_per_group)
- max_debt = inodes_per_group / INODE_COST;
- if (max_debt > 255)
- max_debt = 255;
- if (max_debt == 0)
- max_debt = 1;
- for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (!desc || !desc->bg_free_inodes_count)
- continue;
- if (sbi->s_debts[group] >= max_debt)
- continue;
- if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
- continue;
- if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
- continue;
- if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
- continue;
- goto found;
- }
- fallback:
- for (i = 0; i < ngroups; i++) {
- group = (parent_group + i) % ngroups;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (!desc || !desc->bg_free_inodes_count)
- continue;
- if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
- goto found;
- }
- if (avefreei) {
- /*
- * The free-inodes counter is approximate, and for really small
- * filesystems the above test can fail to find any blockgroups
- */
- avefreei = 0;
- goto fallback;
- }
- return -1;
- found:
- return group;
- }
- static int find_group_other(struct super_block *sb, struct inode *parent)
- {
- int parent_group = EXT2_I(parent)->i_block_group;
- int ngroups = EXT2_SB(sb)->s_groups_count;
- struct ext2_group_desc *desc;
- int group, i;
- /*
- * Try to place the inode in its parent directory
- */
- group = parent_group;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
- le16_to_cpu(desc->bg_free_blocks_count))
- goto found;
- /*
- * We're going to place this inode in a different blockgroup from its
- * parent. We want to cause files in a common directory to all land in
- * the same blockgroup. But we want files which are in a different
- * directory which shares a blockgroup with our parent to land in a
- * different blockgroup.
- *
- * So add our directory's i_ino into the starting point for the hash.
- */
- group = (group + parent->i_ino) % ngroups;
- /*
- * Use a quadratic hash to find a group with a free inode and some
- * free blocks.
- */
- for (i = 1; i < ngroups; i <<= 1) {
- group += i;
- if (group >= ngroups)
- group -= ngroups;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
- le16_to_cpu(desc->bg_free_blocks_count))
- goto found;
- }
- /*
- * That failed: try linear search for a free inode, even if that group
- * has no free blocks.
- */
- group = parent_group;
- for (i = 0; i < ngroups; i++) {
- if (++group >= ngroups)
- group = 0;
- desc = ext2_get_group_desc (sb, group, NULL);
- if (desc && le16_to_cpu(desc->bg_free_inodes_count))
- goto found;
- }
- return -1;
- found:
- return group;
- }
- struct inode *ext2_new_inode(struct inode *dir, umode_t mode,
- const struct qstr *qstr)
- {
- struct super_block *sb;
- struct buffer_head *bitmap_bh = NULL;
- struct buffer_head *bh2;
- int group, i;
- ino_t ino = 0;
- struct inode * inode;
- struct ext2_group_desc *gdp;
- struct ext2_super_block *es;
- struct ext2_inode_info *ei;
- struct ext2_sb_info *sbi;
- int err;
- sb = dir->i_sb;
- inode = new_inode(sb);
- if (!inode)
- return ERR_PTR(-ENOMEM);
- ei = EXT2_I(inode);
- sbi = EXT2_SB(sb);
- es = sbi->s_es;
- if (S_ISDIR(mode)) {
- if (test_opt(sb, OLDALLOC))
- group = find_group_dir(sb, dir);
- else
- group = find_group_orlov(sb, dir);
- } else
- group = find_group_other(sb, dir);
- if (group == -1) {
- err = -ENOSPC;
- goto fail;
- }
- for (i = 0; i < sbi->s_groups_count; i++) {
- gdp = ext2_get_group_desc(sb, group, &bh2);
- brelse(bitmap_bh);
- bitmap_bh = read_inode_bitmap(sb, group);
- if (!bitmap_bh) {
- err = -EIO;
- goto fail;
- }
- ino = 0;
- repeat_in_this_group:
- ino = ext2_find_next_zero_bit((unsigned long *)bitmap_bh->b_data,
- EXT2_INODES_PER_GROUP(sb), ino);
- if (ino >= EXT2_INODES_PER_GROUP(sb)) {
- /*
- * Rare race: find_group_xx() decided that there were
- * free inodes in this group, but by the time we tried
- * to allocate one, they're all gone. This can also
- * occur because the counters which find_group_orlov()
- * uses are approximate. So just go and search the
- * next block group.
- */
- if (++group == sbi->s_groups_count)
- group = 0;
- continue;
- }
- if (ext2_set_bit_atomic(sb_bgl_lock(sbi, group),
- ino, bitmap_bh->b_data)) {
- /* we lost this inode */
- if (++ino >= EXT2_INODES_PER_GROUP(sb)) {
- /* this group is exhausted, try next group */
- if (++group == sbi->s_groups_count)
- group = 0;
- continue;
- }
- /* try to find free inode in the same group */
- goto repeat_in_this_group;
- }
- goto got;
- }
- /*
- * Scanned all blockgroups.
- */
- err = -ENOSPC;
- goto fail;
- got:
- mark_buffer_dirty(bitmap_bh);
- if (sb->s_flags & MS_SYNCHRONOUS)
- sync_dirty_buffer(bitmap_bh);
- brelse(bitmap_bh);
- ino += group * EXT2_INODES_PER_GROUP(sb) + 1;
- if (ino < EXT2_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
- ext2_error (sb, "ext2_new_inode",
- "reserved inode or inode > inodes count - "
- "block_group = %d,inode=%lu", group,
- (unsigned long) ino);
- err = -EIO;
- goto fail;
- }
- percpu_counter_add(&sbi->s_freeinodes_counter, -1);
- if (S_ISDIR(mode))
- percpu_counter_inc(&sbi->s_dirs_counter);
- spin_lock(sb_bgl_lock(sbi, group));
- le16_add_cpu(&gdp->bg_free_inodes_count, -1);
- if (S_ISDIR(mode)) {
- if (sbi->s_debts[group] < 255)
- sbi->s_debts[group]++;
- le16_add_cpu(&gdp->bg_used_dirs_count, 1);
- } else {
- if (sbi->s_debts[group])
- sbi->s_debts[group]--;
- }
- spin_unlock(sb_bgl_lock(sbi, group));
- mark_buffer_dirty(bh2);
- if (test_opt(sb, GRPID)) {
- inode->i_mode = mode;
- inode->i_uid = current_fsuid();
- inode->i_gid = dir->i_gid;
- } else
- inode_init_owner(inode, dir, mode);
- inode->i_ino = ino;
- inode->i_blocks = 0;
- inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
- memset(ei->i_data, 0, sizeof(ei->i_data));
- ei->i_flags =
- ext2_mask_flags(mode, EXT2_I(dir)->i_flags & EXT2_FL_INHERITED);
- ei->i_faddr = 0;
- ei->i_frag_no = 0;
- ei->i_frag_size = 0;
- ei->i_file_acl = 0;
- ei->i_dir_acl = 0;
- ei->i_dtime = 0;
- ei->i_block_alloc_info = NULL;
- ei->i_block_group = group;
- ei->i_dir_start_lookup = 0;
- ei->i_state = EXT2_STATE_NEW;
- ext2_set_inode_flags(inode);
- spin_lock(&sbi->s_next_gen_lock);
- inode->i_generation = sbi->s_next_generation++;
- spin_unlock(&sbi->s_next_gen_lock);
- if (insert_inode_locked(inode) < 0) {
- ext2_error(sb, "ext2_new_inode",
- "inode number already in use - inode=%lu",
- (unsigned long) ino);
- err = -EIO;
- goto fail;
- }
- err = dquot_initialize(inode);
- if (err)
- goto fail_drop;
- err = dquot_alloc_inode(inode);
- if (err)
- goto fail_drop;
- err = ext2_init_acl(inode, dir);
- if (err)
- goto fail_free_drop;
- err = ext2_init_security(inode, dir, qstr);
- if (err)
- goto fail_free_drop;
- mark_inode_dirty(inode);
- ext2_debug("allocating inode %lu\n", inode->i_ino);
- ext2_preread_inode(inode);
- return inode;
- fail_free_drop:
- dquot_free_inode(inode);
- fail_drop:
- dquot_drop(inode);
- inode->i_flags |= S_NOQUOTA;
- clear_nlink(inode);
- unlock_new_inode(inode);
- iput(inode);
- return ERR_PTR(err);
- fail:
- make_bad_inode(inode);
- iput(inode);
- return ERR_PTR(err);
- }
- unsigned long ext2_count_free_inodes (struct super_block * sb)
- {
- struct ext2_group_desc *desc;
- unsigned long desc_count = 0;
- int i;
- #ifdef EXT2FS_DEBUG
- struct ext2_super_block *es;
- unsigned long bitmap_count = 0;
- struct buffer_head *bitmap_bh = NULL;
- es = EXT2_SB(sb)->s_es;
- for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
- unsigned x;
- desc = ext2_get_group_desc (sb, i, NULL);
- if (!desc)
- continue;
- desc_count += le16_to_cpu(desc->bg_free_inodes_count);
- brelse(bitmap_bh);
- bitmap_bh = read_inode_bitmap(sb, i);
- if (!bitmap_bh)
- continue;
- x = ext2_count_free(bitmap_bh, EXT2_INODES_PER_GROUP(sb) / 8);
- printk("group %d: stored = %d, counted = %u\n",
- i, le16_to_cpu(desc->bg_free_inodes_count), x);
- bitmap_count += x;
- }
- brelse(bitmap_bh);
- printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
- (unsigned long)
- percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
- desc_count, bitmap_count);
- return desc_count;
- #else
- for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
- desc = ext2_get_group_desc (sb, i, NULL);
- if (!desc)
- continue;
- desc_count += le16_to_cpu(desc->bg_free_inodes_count);
- }
- return desc_count;
- #endif
- }
- /* Called at mount-time, super-block is locked */
- unsigned long ext2_count_dirs (struct super_block * sb)
- {
- unsigned long count = 0;
- int i;
- for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
- struct ext2_group_desc *gdp = ext2_get_group_desc (sb, i, NULL);
- if (!gdp)
- continue;
- count += le16_to_cpu(gdp->bg_used_dirs_count);
- }
- return count;
- }
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