| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * 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)); |
| percpu_counter_inc(&EXT2_SB(sb)->s_freeinodes_counter); |
| 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 & SB_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; |
| |
| 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; |
| } |
| } |
| |
| 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); |
| if (!gdp) { |
| if (++group == sbi->s_groups_count) |
| group = 0; |
| continue; |
| } |
| 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. |
| */ |
| brelse(bitmap_bh); |
| err = -ENOSPC; |
| goto fail; |
| got: |
| mark_buffer_dirty(bitmap_bh); |
| if (sb->s_flags & SB_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_dec(&sbi->s_freeinodes_counter); |
| 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(&init_user_ns, inode, dir, mode); |
| |
| inode->i_ino = ino; |
| inode->i_blocks = 0; |
| inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode); |
| 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); |
| discard_new_inode(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; |
| } |
| |