/*
* linux/fs/ext3/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/config.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd.h>
#include <linux/ext3_fs.h>
#include <linux/ext3_jbd.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
/*
* balloc.c contains the blocks allocation and deallocation routines
*/
/*
* 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 ext3_read_super).
*/
#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
unsigned int block_group,
struct buffer_head ** bh)
{
unsigned long group_desc;
unsigned long desc;
struct ext3_group_desc * gdp;
if (block_group >= EXT3_SB(sb)->s_groups_count) {
ext3_error (sb, "ext3_get_group_desc",
"block_group >= groups_count - "
"block_group = %d, groups_count = %lu",
block_group, EXT3_SB(sb)->s_groups_count);
return NULL;
}
group_desc = block_group / EXT3_DESC_PER_BLOCK(sb);
desc = block_group % EXT3_DESC_PER_BLOCK(sb);
if (!EXT3_SB(sb)->s_group_desc[group_desc]) {
ext3_error (sb, "ext3_get_group_desc",
"Group descriptor not loaded - "
"block_group = %d, group_desc = %lu, desc = %lu",
block_group, group_desc, desc);
return NULL;
}
gdp = (struct ext3_group_desc *)
EXT3_SB(sb)->s_group_desc[group_desc]->b_data;
if (bh)
*bh = EXT3_SB(sb)->s_group_desc[group_desc];
return gdp + desc;
}
/*
* Read the bitmap for a given block_group, reading into the specified
* slot in the superblock's bitmap cache.
*
* Return buffer_head on success or NULL in case of failure.
*/
static struct buffer_head *
read_block_bitmap(struct super_block *sb, unsigned int block_group)
{
struct ext3_group_desc * desc;
struct buffer_head * bh = NULL;
desc = ext3_get_group_desc (sb, block_group, NULL);
if (!desc)
goto error_out;
bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
if (!bh)
ext3_error (sb, "read_block_bitmap",
"Cannot read block bitmap - "
"block_group = %d, block_bitmap = %lu",
block_group, (unsigned long) desc->bg_block_bitmap);
error_out:
return bh;
}
/* Free given blocks, update quota and i_blocks field */
void ext3_free_blocks (handle_t *handle, struct inode * inode,
unsigned long block, unsigned long count)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gd_bh;
unsigned long block_group;
unsigned long bit;
unsigned long i;
unsigned long overflow;
struct super_block * sb;
struct ext3_group_desc * gdp;
struct ext3_super_block * es;
struct ext3_sb_info *sbi;
int err = 0, ret;
int dquot_freed_blocks = 0;
sb = inode->i_sb;
if (!sb) {
printk ("ext3_free_blocks: nonexistent device");
return;
}
sbi = EXT3_SB(sb);
es = EXT3_SB(sb)->s_es;
if (block < le32_to_cpu(es->s_first_data_block) ||
block + count < block ||
block + count > le32_to_cpu(es->s_blocks_count)) {
ext3_error (sb, "ext3_free_blocks",
"Freeing blocks not in datazone - "
"block = %lu, count = %lu", block, count);
goto error_return;
}
ext3_debug ("freeing block %lu\n", block);
do_more:
overflow = 0;
block_group = (block - le32_to_cpu(es->s_first_data_block)) /
EXT3_BLOCKS_PER_GROUP(sb);
bit = (block - le32_to_cpu(es->s_first_data_block)) %
EXT3_BLOCKS_PER_GROUP(sb);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
count -= overflow;
}
brelse(bitmap_bh);
bitmap_bh = read_block_bitmap(sb, block_group);
if (!bitmap_bh)
goto error_return;
gdp = ext3_get_group_desc (sb, block_group, &gd_bh);
if (!gdp)
goto error_return;
if (in_range (le32_to_cpu(gdp->bg_block_bitmap), block, count) ||
in_range (le32_to_cpu(gdp->bg_inode_bitmap), block, count) ||
in_range (block, le32_to_cpu(gdp->bg_inode_table),
EXT3_SB(sb)->s_itb_per_group) ||
in_range (block + count - 1, le32_to_cpu(gdp->bg_inode_table),
EXT3_SB(sb)->s_itb_per_group))
ext3_error (sb, "ext3_free_blocks",
"Freeing blocks in system zones - "
"Block = %lu, count = %lu",
block, count);
/*
* We are about to start releasing blocks in the bitmap,
* so we need undo access.
*/
/* @@@ check errors */
BUFFER_TRACE(bitmap_bh, "getting undo access");
err = ext3_journal_get_undo_access(handle, bitmap_bh, NULL);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext3_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
jbd_lock_bh_state(bitmap_bh);
for (i = 0; i < count; i++) {
/*
* An HJ special. This is expensive...
*/
#ifdef CONFIG_JBD_DEBUG
jbd_unlock_bh_state(bitmap_bh);
{
struct buffer_head *debug_bh;
debug_bh = sb_find_get_block(sb, block + i);
if (debug_bh) {
BUFFER_TRACE(debug_bh, "Deleted!");
if (!bh2jh(bitmap_bh)->b_committed_data)
BUFFER_TRACE(debug_bh,
"No commited data in bitmap");
BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
__brelse(debug_bh);
}
}
jbd_lock_bh_state(bitmap_bh);
#endif
/* @@@ This prevents newly-allocated data from being
* freed and then reallocated within the same
* transaction.
*
* Ideally we would want to allow that to happen, but to
* do so requires making journal_forget() capable of
* revoking the queued write of a data block, which
* implies blocking on the journal lock. *forget()
* cannot block due to truncate races.
*
* Eventually we can fix this by making journal_forget()
* return a status indicating whether or not it was able
* to revoke the buffer. On successful revoke, it is
* safe not to set the allocation bit in the committed
* bitmap, because we know that there is no outstanding
* activity on the buffer any more and so it is safe to
* reallocate it.
*/
BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
J_ASSERT_BH(bitmap_bh,
bh2jh(bitmap_bh)->b_committed_data != NULL);
ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
bh2jh(bitmap_bh)->b_committed_data);
/*
* We clear the bit in the bitmap after setting the committed
* data bit, because this is the reverse order to that which
* the allocator uses.
*/
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
bit + i, bitmap_bh->b_data)) {
jbd_unlock_bh_state(bitmap_bh);
ext3_error(sb, __FUNCTION__,
"bit already cleared for block %lu", block + i);
jbd_lock_bh_state(bitmap_bh);
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
dquot_freed_blocks++;
}
}
jbd_unlock_bh_state(bitmap_bh);
spin_lock(sb_bgl_lock(sbi, block_group));
gdp->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) +
dquot_freed_blocks);
spin_unlock(sb_bgl_lock(sbi, block_group));
percpu_counter_mod(&sbi->s_freeblocks_counter, count);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext3_journal_dirty_metadata(handle, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext3_journal_dirty_metadata(handle, gd_bh);
if (!err) err = ret;
if (overflow && !err) {
block += count;
count = overflow;
goto do_more;
}
sb->s_dirt = 1;
error_return:
brelse(bitmap_bh);
ext3_std_error(sb, err);
if (dquot_freed_blocks)
DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
return;
}
/*
* For ext3 allocations, we must not reuse any blocks which are
* allocated in the bitmap buffer's "last committed data" copy. This
* prevents deletes from freeing up the page for reuse until we have
* committed the delete transaction.
*
* If we didn't do this, then deleting something and reallocating it as
* data would allow the old block to be overwritten before the
* transaction committed (because we force data to disk before commit).
* This would lead to corruption if we crashed between overwriting the
* data and committing the delete.
*
* @@@ We may want to make this allocation behaviour conditional on
* data-writes at some point, and disable it for metadata allocations or
* sync-data inodes.
*/
static inline int ext3_test_allocatable(int nr, struct buffer_head *bh)
{
int ret;
struct journal_head *jh = bh2jh(bh);
if (ext3_test_bit(nr, bh->b_data))
return 0;
jbd_lock_bh_state(bh);
if (!jh->b_committed_data)
ret = 1;
else
ret = !ext3_test_bit(nr, jh->b_committed_data);
jbd_unlock_bh_state(bh);
return ret;
}
/*
* Find an allocatable block in a bitmap. We honour both the bitmap and
* its last-committed copy (if that exists), and perform the "most
* appropriate allocation" algorithm of looking for a free block near
* the initial goal; then for a free byte somewhere in the bitmap; then
* for any free bit in the bitmap.
*/
static int
find_next_usable_block(int start, struct buffer_head *bh, int maxblocks)
{
int here, next;
char *p, *r;
struct journal_head *jh = bh2jh(bh);
if (start > 0) {
/*
* The goal was occupied; search forward for a free
* block within the next XX blocks.
*
* end_goal is more or less random, but it has to be
* less than EXT3_BLOCKS_PER_GROUP. Aligning up to the
* next 64-bit boundary is simple..
*/
int end_goal = (start + 63) & ~63;
here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
if (here < end_goal && ext3_test_allocatable(here, bh))
return here;
ext3_debug("Bit not found near goal\n");
}
here = start;
if (here < 0)
here = 0;
p = ((char *)bh->b_data) + (here >> 3);
r = memscan(p, 0, (maxblocks - here + 7) >> 3);
next = (r - ((char *)bh->b_data)) << 3;
if (next < maxblocks && ext3_test_allocatable(next, bh))
return next;
/*
* The bitmap search --- search forward alternately through the actual
* bitmap and the last-committed copy until we find a bit free in
* both
*/
while (here < maxblocks) {
next = ext3_find_next_zero_bit(bh->b_data, maxblocks, here);
if (next >= maxblocks)
return -1;
if (ext3_test_allocatable(next, bh))
return next;
jbd_lock_bh_state(bh);
if (jh->b_committed_data)
here = ext3_find_next_zero_bit(jh->b_committed_data,
maxblocks, next);
jbd_unlock_bh_state(bh);
}
return -1;
}
/*
* We think we can allocate this block in this bitmap. Try to set the bit.
* If that succeeds then check that nobody has allocated and then freed the
* block since we saw that is was not marked in b_committed_data. If it _was_
* allocated and freed then clear the bit in the bitmap again and return
* zero (failure).
*/
static inline int
claim_block(spinlock_t *lock, int block, struct buffer_head *bh)
{
struct journal_head *jh = bh2jh(bh);
int ret;
if (ext3_set_bit_atomic(lock, block, bh->b_data))
return 0;
jbd_lock_bh_state(bh);
if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) {
ext3_clear_bit_atomic(lock, block, bh->b_data);
ret = 0;
} else {
ret = 1;
}
jbd_unlock_bh_state(bh);
return ret;
}
/*
* If we failed to allocate the desired block then we may end up crossing to a
* new bitmap. In that case we must release write access to the old one via
* ext3_journal_release_buffer(), else we'll run out of credits.
*/
static int
ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
struct buffer_head *bitmap_bh, int goal, int *errp)
{
int i;
int fatal;
int credits = 0;
*errp = 0;
/*
* Make sure we use undo access for the bitmap, because it is critical
* that we do the frozen_data COW on bitmap buffers in all cases even
* if the buffer is in BJ_Forget state in the committing transaction.
*/
BUFFER_TRACE(bitmap_bh, "get undo access for new block");
fatal = ext3_journal_get_undo_access(handle, bitmap_bh, &credits);
if (fatal) {
*errp = fatal;
goto fail;
}
repeat:
if (goal < 0 || !ext3_test_allocatable(goal, bitmap_bh)) {
goal = find_next_usable_block(goal, bitmap_bh,
EXT3_BLOCKS_PER_GROUP(sb));
if (goal < 0)
goto fail_access;
for (i = 0; i < 7 && goal > 0 &&
ext3_test_allocatable(goal - 1, bitmap_bh);
i++, goal--);
}
if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group), goal, bitmap_bh)) {
/*
* The block was allocated by another thread, or it was
* allocated and then freed by another thread
*/
goal++;
if (goal >= EXT3_BLOCKS_PER_GROUP(sb))
goto fail_access;
goto repeat;
}
BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for bitmap block");
fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
if (fatal) {
*errp = fatal;
goto fail;
}
return goal;
fail_access:
BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
ext3_journal_release_buffer(handle, bitmap_bh, credits);
fail:
return -1;
}
/*
* ext3_new_block uses a goal block to assist allocation. If the goal is
* free, or there is a free block within 32 blocks of the goal, that block
* is allocated. Otherwise a forward search is made for a free block; within
* each block group the search first looks for an entire free byte in the block
* bitmap, and then for any free bit if that fails.
* This function also updates quota and i_blocks field.
*/
int
ext3_new_block(handle_t *handle, struct inode *inode, unsigned long goal,
u32 *prealloc_count, u32 *prealloc_block, int *errp)
{
struct buffer_head *bitmap_bh = NULL; /* bh */
struct buffer_head *gdp_bh; /* bh2 */
int group_no; /* i */
int ret_block; /* j */
int bgi; /* blockgroup iteration index */
int target_block; /* tmp */
int fatal = 0, err;
int performed_allocation = 0;
int free_blocks, root_blocks;
struct super_block *sb;
struct ext3_group_desc *gdp;
struct ext3_super_block *es;
struct ext3_sb_info *sbi;
#ifdef EXT3FS_DEBUG
static int goal_hits, goal_attempts;
#endif
*errp = -ENOSPC;
sb = inode->i_sb;
if (!sb) {
printk("ext3_new_block: nonexistent device");
return 0;
}
/*
* Check quota for allocation of this block.
*/
if (DQUOT_ALLOC_BLOCK(inode, 1)) {
*errp = -EDQUOT;
return 0;
}
sbi = EXT3_SB(sb);
es = EXT3_SB(sb)->s_es;
ext3_debug("goal=%lu.\n", goal);
free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
root_blocks = le32_to_cpu(es->s_r_blocks_count);
if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
sbi->s_resuid != current->fsuid &&
(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
*errp = -ENOSPC;
goto out;
}
/*
* First, test whether the goal block is free.
*/
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= le32_to_cpu(es->s_blocks_count))
goal = le32_to_cpu(es->s_first_data_block);
group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
EXT3_BLOCKS_PER_GROUP(sb);
gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
if (!gdp)
goto io_error;
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
if (free_blocks > 0) {
ret_block = ((goal - le32_to_cpu(es->s_first_data_block)) %
EXT3_BLOCKS_PER_GROUP(sb));
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
ret_block = ext3_try_to_allocate(sb, handle, group_no,
bitmap_bh, ret_block, &fatal);
if (fatal)
goto out;
if (ret_block >= 0)
goto allocated;
}
/*
* Now search the rest of the groups. We assume that
* i and gdp correctly point to the last group visited.
*/
for (bgi = 0; bgi < EXT3_SB(sb)->s_groups_count; bgi++) {
group_no++;
if (group_no >= EXT3_SB(sb)->s_groups_count)
group_no = 0;
gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
if (!gdp) {
*errp = -EIO;
goto out;
}
free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
if (free_blocks <= 0)
continue;
brelse(bitmap_bh);
bitmap_bh = read_block_bitmap(sb, group_no);
if (!bitmap_bh)
goto io_error;
ret_block = ext3_try_to_allocate(sb, handle, group_no,
bitmap_bh, -1, &fatal);
if (fatal)
goto out;
if (ret_block >= 0)
goto allocated;
}
/* No space left on the device */
*errp = -ENOSPC;
goto out;
allocated:
ext3_debug("using block group %d(%d)\n",
group_no, gdp->bg_free_blocks_count);
BUFFER_TRACE(gdp_bh, "get_write_access");
fatal = ext3_journal_get_write_access(handle, gdp_bh);
if (fatal)
goto out;
target_block = ret_block + group_no * EXT3_BLOCKS_PER_GROUP(sb)
+ le32_to_cpu(es->s_first_data_block);
if (target_block == le32_to_cpu(gdp->bg_block_bitmap) ||
target_block == le32_to_cpu(gdp->bg_inode_bitmap) ||
in_range(target_block, le32_to_cpu(gdp->bg_inode_table),
EXT3_SB(sb)->s_itb_per_group))
ext3_error(sb, "ext3_new_block",
"Allocating block in system zone - "
"block = %u", target_block);
performed_allocation = 1;
#ifdef CONFIG_JBD_DEBUG
{
struct buffer_head *debug_bh;
/* Record bitmap buffer state in the newly allocated block */
debug_bh = sb_find_get_block(sb, target_block);
if (debug_bh) {
BUFFER_TRACE(debug_bh, "state when allocated");
BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
brelse(debug_bh);
}
}
jbd_lock_bh_state(bitmap_bh);
spin_lock(sb_bgl_lock(sbi, group_no));
if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
if (ext3_test_bit(ret_block,
bh2jh(bitmap_bh)->b_committed_data)) {
printk("%s: block was unexpectedly set in "
"b_committed_data\n", __FUNCTION__);
}
}
ext3_debug("found bit %d\n", ret_block);
spin_unlock(sb_bgl_lock(sbi, group_no));
jbd_unlock_bh_state(bitmap_bh);
#endif
/* ret_block was blockgroup-relative. Now it becomes fs-relative */
ret_block = target_block;
if (ret_block >= le32_to_cpu(es->s_blocks_count)) {
ext3_error(sb, "ext3_new_block",
"block(%d) >= blocks count(%d) - "
"block_group = %d, es == %p ", ret_block,
le32_to_cpu(es->s_blocks_count), group_no, es);
goto out;
}
/*
* It is up to the caller to add the new buffer to a journal
* list of some description. We don't know in advance whether
* the caller wants to use it as metadata or data.
*/
ext3_debug("allocating block %d. Goal hits %d of %d.\n",
ret_block, goal_hits, goal_attempts);
spin_lock(sb_bgl_lock(sbi, group_no));
gdp->bg_free_blocks_count =
cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count) - 1);
spin_unlock(sb_bgl_lock(sbi, group_no));
percpu_counter_mod(&sbi->s_freeblocks_counter, -1);
BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
err = ext3_journal_dirty_metadata(handle, gdp_bh);
if (!fatal)
fatal = err;
sb->s_dirt = 1;
if (fatal)
goto out;
*errp = 0;
brelse(bitmap_bh);
return ret_block;
io_error:
*errp = -EIO;
out:
if (fatal) {
*errp = fatal;
ext3_std_error(sb, fatal);
}
/*
* Undo the block allocation
*/
if (!performed_allocation)
DQUOT_FREE_BLOCK(inode, 1);
brelse(bitmap_bh);
return 0;
}
unsigned long ext3_count_free_blocks(struct super_block *sb)
{
unsigned long desc_count;
struct ext3_group_desc *gdp;
int i;
#ifdef EXT3FS_DEBUG
struct ext3_super_block *es;
unsigned long bitmap_count, x;
struct buffer_head *bitmap_bh = NULL;
lock_super(sb);
es = EXT3_SB(sb)->s_es;
desc_count = 0;
bitmap_count = 0;
gdp = NULL;
for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
gdp = ext3_get_group_desc(sb, i, NULL);
if (!gdp)
continue;
desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
brelse(bitmap_bh);
bitmap_bh = read_block_bitmap(sb, i);
if (bitmap_bh == NULL)
continue;
x = ext3_count_free(bitmap_bh, sb->s_blocksize);
printk("group %d: stored = %d, counted = %lu\n",
i, le16_to_cpu(gdp->bg_free_blocks_count), x);
bitmap_count += x;
}
brelse(bitmap_bh);
printk("ext3_count_free_blocks: stored = %u, computed = %lu, %lu\n",
le32_to_cpu(es->s_free_blocks_count), desc_count, bitmap_count);
unlock_super(sb);
return bitmap_count;
#else
desc_count = 0;
for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
gdp = ext3_get_group_desc(sb, i, NULL);
if (!gdp)
continue;
desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
}
return desc_count;
#endif
}
static inline int block_in_use(unsigned long block,
struct super_block * sb,
unsigned char * map)
{
return ext3_test_bit ((block -
le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
EXT3_BLOCKS_PER_GROUP(sb), map);
}
static inline int test_root(int a, int b)
{
if (a == 0)
return 1;
while (1) {
if (a == 1)
return 1;
if (a % b)
return 0;
a = a / b;
}
}
int ext3_group_sparse(int group)
{
return (test_root(group, 3) || test_root(group, 5) ||
test_root(group, 7));
}
/**
* ext3_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 ext3_bg_has_super(struct super_block *sb, int group)
{
if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
!ext3_group_sparse(group))
return 0;
return 1;
}
/**
* ext3_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 ext3_bg_num_gdb(struct super_block *sb, int group)
{
if (EXT3_HAS_RO_COMPAT_FEATURE(sb,EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)&&
!ext3_group_sparse(group))
return 0;
return EXT3_SB(sb)->s_gdb_count;
}
#ifdef CONFIG_EXT3_CHECK
/* Called at mount-time, super-block is locked */
void ext3_check_blocks_bitmap (struct super_block * sb)
{
struct ext3_super_block *es;
unsigned long desc_count, bitmap_count, x, j;
unsigned long desc_blocks;
struct buffer_head *bitmap_bh = NULL;
struct ext3_group_desc *gdp;
int i;
es = EXT3_SB(sb)->s_es;
desc_count = 0;
bitmap_count = 0;
gdp = NULL;
for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
gdp = ext3_get_group_desc (sb, i, NULL);
if (!gdp)
continue;
desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
brelse(bitmap_bh);
bitmap_bh = read_block_bitmap(sb, i);
if (bitmap_bh == NULL)
continue;
if (ext3_bg_has_super(sb, i) &&
!ext3_test_bit(0, bitmap_bh->b_data))
ext3_error(sb, __FUNCTION__,
"Superblock in group %d is marked free", i);
desc_blocks = ext3_bg_num_gdb(sb, i);
for (j = 0; j < desc_blocks; j++)
if (!ext3_test_bit(j + 1, bitmap_bh->b_data))
ext3_error(sb, __FUNCTION__,
"Descriptor block #%ld in group "
"%d is marked free", j, i);
if (!block_in_use (le32_to_cpu(gdp->bg_block_bitmap),
sb, bitmap_bh->b_data))
ext3_error (sb, "ext3_check_blocks_bitmap",
"Block bitmap for group %d is marked free",
i);
if (!block_in_use (le32_to_cpu(gdp->bg_inode_bitmap),
sb, bitmap_bh->b_data))
ext3_error (sb, "ext3_check_blocks_bitmap",
"Inode bitmap for group %d is marked free",
i);
for (j = 0; j < EXT3_SB(sb)->s_itb_per_group; j++)
if (!block_in_use (le32_to_cpu(gdp->bg_inode_table) + j,
sb, bitmap_bh->b_data))
ext3_error (sb, "ext3_check_blocks_bitmap",
"Block #%d of the inode table in "
"group %d is marked free", j, i);
x = ext3_count_free(bitmap_bh, sb->s_blocksize);
if (le16_to_cpu(gdp->bg_free_blocks_count) != x)
ext3_error (sb, "ext3_check_blocks_bitmap",
"Wrong free blocks count for group %d, "
"stored = %d, counted = %lu", i,
le16_to_cpu(gdp->bg_free_blocks_count), x);
bitmap_count += x;
}
brelse(bitmap_bh);
if (le32_to_cpu(es->s_free_blocks_count) != bitmap_count)
ext3_error (sb, "ext3_check_blocks_bitmap",
"Wrong free blocks count in super block, "
"stored = %lu, counted = %lu",
(unsigned long)le32_to_cpu(es->s_free_blocks_count),
bitmap_count);
}
#endif
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