/* * 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; }Lines 1–500 of 678. Load more
/* * 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; }