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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/config.h>
#include <linux/fs.h>
#include <linux/ext2_fs.h>
#include <linux/locks.h>
#include <linux/quotaops.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. The descriptors are loaded in memory
* when a file system is mounted (see ext2_read_super).
*/
/*
* 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 = %lu",
block_group, (unsigned long) desc->bg_inode_bitmap);
error_out:
return bh;
}
/*
* load_inode_bitmap loads the inode bitmap for a blocks group
*
* It maintains a cache for the last bitmaps loaded. This cache is managed
* with a LRU algorithm.
*
* Notes:
* 1/ There is one cache per mounted file system.
* 2/ If the file system contains less than EXT2_MAX_GROUP_LOADED groups,
* this function reads the bitmap without maintaining a LRU cache.
*
* Return the buffer_head of the bitmap or the ERR_PTR(error)
*/
static struct buffer_head *load_inode_bitmap (struct super_block * sb,
unsigned int block_group)
{
int i, slot = 0;
struct ext2_sb_info *sbi = &sb->u.ext2_sb;
struct buffer_head *bh = sbi->s_inode_bitmap[0];
if (block_group >= sbi->s_groups_count)
ext2_panic (sb, "load_inode_bitmap",
"block_group >= groups_count - "
"block_group = %d, groups_count = %lu",
block_group, sbi->s_groups_count);
if (sbi->s_loaded_inode_bitmaps > 0 &&
sbi->s_inode_bitmap_number[0] == block_group && bh)
goto found;
if (sbi->s_groups_count <= EXT2_MAX_GROUP_LOADED) {
slot = block_group;
bh = sbi->s_inode_bitmap[slot];
if (!bh)
goto read_it;
if (sbi->s_inode_bitmap_number[slot] == slot)
goto found;
ext2_panic (sb, "load_inode_bitmap",
"block_group != inode_bitmap_number");
}
bh = NULL;
for (i = 0; i < sbi->s_loaded_inode_bitmaps &&
sbi->s_inode_bitmap_number[i] != block_group;
i++)
;
if (i < sbi->s_loaded_inode_bitmaps)
bh = sbi->s_inode_bitmap[i];
else if (sbi->s_loaded_inode_bitmaps < EXT2_MAX_GROUP_LOADED)
sbi->s_loaded_inode_bitmaps++;
else
brelse (sbi->s_inode_bitmap[--i]);
while (i--) {
sbi->s_inode_bitmap_number[i+1] = sbi->s_inode_bitmap_number[i];
sbi->s_inode_bitmap[i+1] = sbi->s_inode_bitmap[i];
}
read_it:
if (!bh)
bh = read_inode_bitmap (sb, block_group);
sbi->s_inode_bitmap_number[slot] = block_group;
sbi->s_inode_bitmap[slot] = bh;
if (!bh)
return ERR_PTR(-EIO);
found:
return 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 * bh;
struct buffer_head * bh2;
unsigned long block_group;
unsigned long bit;
struct ext2_group_desc * desc;
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.
*/
if (!is_bad_inode(inode)) {
/* Quota is already initialized in iput() */
DQUOT_FREE_INODE(inode);
DQUOT_DROP(inode);
}
lock_super (sb);
es = sb->u.ext2_sb.s_es;
is_directory = S_ISDIR(inode->i_mode);
/* Do this BEFORE marking the inode not in use or returning an error */
clear_inode (inode);
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);
goto error_return;
}
block_group = (ino - 1) / EXT2_INODES_PER_GROUP(sb);
bit = (ino - 1) % EXT2_INODES_PER_GROUP(sb);
bh = load_inode_bitmap (sb, block_group);
if (IS_ERR(bh))
goto error_return;
/* Ok, now we can actually update the inode bitmaps.. */
if (!ext2_clear_bit (bit, bh->b_data))
ext2_error (sb, "ext2_free_inode",
"bit already cleared for inode %lu", ino);
else {
desc = ext2_get_group_desc (sb, block_group, &bh2);
if (desc) {
desc->bg_free_inodes_count =
cpu_to_le16(le16_to_cpu(desc->bg_free_inodes_count) + 1);
if (is_directory)
desc->bg_used_dirs_count =
cpu_to_le16(le16_to_cpu(desc->bg_used_dirs_count) - 1);
}
mark_buffer_dirty(bh2);
es->s_free_inodes_count =
cpu_to_le32(le32_to_cpu(es->s_free_inodes_count) + 1);
mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
}
mark_buffer_dirty(bh);
if (sb->s_flags & MS_SYNCHRONOUS) {
ll_rw_block (WRITE, 1, &bh);
wait_on_buffer (bh);
}
sb->s_dirt = 1;
error_return:
unlock_super (sb);
}
/*
* 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, int parent_group)
{
struct ext2_super_block * es = sb->u.ext2_sb.s_es;
int ngroups = sb->u.ext2_sb.s_groups_count;
int avefreei = le32_to_cpu(es->s_free_inodes_count) / ngroups;
struct ext2_group_desc *desc, *best_desc = NULL;
struct buffer_head *bh, *best_bh = NULL;
int group, best_group = -1;
for (group = 0; group < ngroups; group++) {
desc = ext2_get_group_desc (sb, group, &bh);
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;
best_bh = bh;
}
}
if (!best_desc)
return -1;
best_desc->bg_free_inodes_count =
cpu_to_le16(le16_to_cpu(best_desc->bg_free_inodes_count) - 1);
best_desc->bg_used_dirs_count =
cpu_to_le16(le16_to_cpu(best_desc->bg_used_dirs_count) + 1);
mark_buffer_dirty(best_bh);
return best_group;
}
static int find_group_other(struct super_block *sb, int parent_group)
{
int ngroups = sb->u.ext2_sb.s_groups_count;
struct ext2_group_desc *desc;
struct buffer_head *bh;
int group, i;
/*
* Try to place the inode in its parent directory
*/
group = parent_group;
desc = ext2_get_group_desc (sb, group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count))
goto found;
/*
* Use a quadratic hash to find a group with a
* free inode
*/
for (i = 1; i < ngroups; i <<= 1) {
group += i;
if (group >= ngroups)
group -= ngroups;
desc = ext2_get_group_desc (sb, group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count))
goto found;
}
/*
* That failed: try linear search for a free inode
*/
group = parent_group + 1;
for (i = 2; i < ngroups; i++) {
if (++group >= ngroups)
group = 0;
desc = ext2_get_group_desc (sb, group, &bh);
if (desc && le16_to_cpu(desc->bg_free_inodes_count))
goto found;
}
return -1;
found:
desc->bg_free_inodes_count =
cpu_to_le16(le16_to_cpu(desc->bg_free_inodes_count) - 1);
mark_buffer_dirty(bh);
return group;
}
struct inode * ext2_new_inode (const struct inode * dir, int mode)
{
struct super_block * sb;
struct buffer_head * bh;
struct buffer_head * bh2;
int group, i;
ino_t ino;
struct inode * inode;
struct ext2_group_desc * desc;
struct ext2_super_block * es;
int err;
sb = dir->i_sb;
inode = new_inode(sb);
if (!inode)
return ERR_PTR(-ENOMEM);
lock_super (sb);
es = sb->u.ext2_sb.s_es;
repeat:
if (S_ISDIR(mode))
group = find_group_dir(sb, dir->u.ext2_i.i_block_group);
else
group = find_group_other(sb, dir->u.ext2_i.i_block_group);
err = -ENOSPC;
if (group == -1)
goto fail;
err = -EIO;
bh = load_inode_bitmap (sb, group);
if (IS_ERR(bh))
goto fail2;
i = ext2_find_first_zero_bit ((unsigned long *) bh->b_data,
EXT2_INODES_PER_GROUP(sb));
if (i >= EXT2_INODES_PER_GROUP(sb))
goto bad_count;
ext2_set_bit (i, bh->b_data);
mark_buffer_dirty(bh);
if (sb->s_flags & MS_SYNCHRONOUS) {
ll_rw_block (WRITE, 1, &bh);
wait_on_buffer (bh);
}
ino = group * EXT2_INODES_PER_GROUP(sb) + i + 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=%ld", group, ino);
err = -EIO;
goto fail2;
}
es->s_free_inodes_count =
cpu_to_le32(le32_to_cpu(es->s_free_inodes_count) - 1);
mark_buffer_dirty(sb->u.ext2_sb.s_sbh);
sb->s_dirt = 1;
inode->i_uid = current->fsuid;
if (test_opt (sb, GRPID))
inode->i_gid = dir->i_gid;
else if (dir->i_mode & S_ISGID) {
inode->i_gid = dir->i_gid;
if (S_ISDIR(mode))
mode |= S_ISGID;
} else
inode->i_gid = current->fsgid;
inode->i_mode = mode;
inode->i_ino = ino;
inode->i_blksize = PAGE_SIZE; /* This is the optimal IO size (for stat), not the fs block size */
inode->i_blocks = 0;
inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
inode->u.ext2_i.i_new_inode = 1;
inode->u.ext2_i.i_flags = dir->u.ext2_i.i_flags;
if (S_ISLNK(mode))
inode->u.ext2_i.i_flags &= ~(EXT2_IMMUTABLE_FL|EXT2_APPEND_FL);
inode->u.ext2_i.i_block_group = group;
if (inode->u.ext2_i.i_flags & EXT2_SYNC_FL)
inode->i_flags |= S_SYNC;
insert_inode_hash(inode);
inode->i_generation = event++;
mark_inode_dirty(inode);
unlock_super (sb);
if(DQUOT_ALLOC_INODE(inode)) {
DQUOT_DROP(inode);
inode->i_flags |= S_NOQUOTA;
inode->i_nlink = 0;
iput(inode);
return ERR_PTR(-EDQUOT);
}
ext2_debug ("allocating inode %lu\n", inode->i_ino);
return inode;
fail2:
desc = ext2_get_group_desc (sb, group, &bh2);
desc->bg_free_inodes_count =
cpu_to_le16(le16_to_cpu(desc->bg_free_inodes_count) + 1);
if (S_ISDIR(mode))
desc->bg_used_dirs_count =
cpu_to_le16(le16_to_cpu(desc->bg_used_dirs_count) - 1);
mark_buffer_dirty(bh2);
fail:
unlock_super(sb);
make_bad_inode(inode);
iput(inode);
return ERR_PTR(err);
bad_count:
ext2_error (sb, "ext2_new_inode",
"Free inodes count corrupted in group %d",
group);
/* Is it really ENOSPC? */
err = -ENOSPC;
if (sb->s_flags & MS_RDONLY)
goto fail;
desc = ext2_get_group_desc (sb, group, &bh2);
desc->bg_free_inodes_count = 0;
mark_buffer_dirty(bh2);
goto repeat;
}
unsigned long ext2_count_free_inodes (struct super_block * sb)
{
#ifdef EXT2FS_DEBUG
struct ext2_super_block * es;
unsigned long desc_count = 0, bitmap_count = 0;
int i;
lock_super (sb);
es = sb->u.ext2_sb.s_es;
for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
struct ext2_group_desc *desc = ext2_get_group_desc (sb, i, NULL);
struct buffer_head *bh;
unsigned x;
if (!desc)
continue;
desc_count += le16_to_cpu(desc->bg_free_inodes_count);
bh = load_inode_bitmap (sb, i);
if (IS_ERR(bh))
continue;
x = ext2_count_free (bh, EXT2_INODES_PER_GROUP(sb) / 8);
printk ("group %d: stored = %d, counted = %lu\n",
i, le16_to_cpu(desc->bg_free_inodes_count), x);
bitmap_count += x;
}
printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
unlock_super (sb);
return desc_count;
#else
return le32_to_cpu(sb->u.ext2_sb.s_es->s_free_inodes_count);
#endif
}
#ifdef CONFIG_EXT2_CHECK
/* Called at mount-time, super-block is locked */
void ext2_check_inodes_bitmap (struct super_block * sb)
{
struct ext2_super_block * es = sb->u.ext2_sb.s_es;
unsigned long desc_count = 0, bitmap_count = 0;
int i;
for (i = 0; i < sb->u.ext2_sb.s_groups_count; i++) {
struct ext2_group_desc *desc = ext2_get_group_desc(sb, i, NULL);
struct buffer_head *bh;
unsigned x;
if (!desc)
continue;
desc_count += le16_to_cpu(desc->bg_free_inodes_count);
bh = load_inode_bitmap (sb, i);
if (IS_ERR(bh))
continue;
x = ext2_count_free (bh, EXT2_INODES_PER_GROUP(sb) / 8);
if (le16_to_cpu(desc->bg_free_inodes_count) != x)
ext2_error (sb, "ext2_check_inodes_bitmap",
"Wrong free inodes count in group %d, "
"stored = %d, counted = %lu", i,
le16_to_cpu(desc->bg_free_inodes_count), x);
bitmap_count += x;
}
if (le32_to_cpu(es->s_free_inodes_count) != bitmap_count)
ext2_error (sb, "ext2_check_inodes_bitmap",
"Wrong free inodes count in super block, "
"stored = %lu, counted = %lu",
(unsigned long)le32_to_cpu(es->s_free_inodes_count),
bitmap_count);
}
#endif
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