linux/fs/ext4/balloc.c
Frederic Bohe c806e68f56 ext4: fix initialization of UNINIT bitmap blocks
This fixes a bug which caused on-line resizing of filesystems with a
1k blocksize to fail.  The root cause of this bug was the fact that if
an uninitalized bitmap block gets read in by userspace (which
e2fsprogs does try to avoid, but can happen when the blocksize is less
than the pagesize and an adjacent blocks is read into memory)
ext4_read_block_bitmap() was erroneously depending on the buffer
uptodate flag to decide whether it needed to initialize the bitmap
block in memory --- i.e., to set the standard set of blocks in use by
a block group (superblock, bitmaps, inode table, etc.).  Essentially,
ext4_read_block_bitmap() assumed it was the only routine that might
try to read a block containing a block bitmap, which is simply not
true.  

To fix this, ext4_read_block_bitmap() and ext4_read_inode_bitmap()
must always initialize uninitialized bitmap blocks.  Once a block or
inode is allocated out of that bitmap, it will be marked as
initialized in the block group descriptor, so in general this won't
result any extra unnecessary work.

Signed-off-by: Frederic Bohe <frederic.bohe@bull.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2008-10-10 08:09:18 -04:00

914 lines
26 KiB
C

/*
* linux/fs/ext4/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/time.h>
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
#include <linux/quotaops.h>
#include <linux/buffer_head.h>
#include "ext4.h"
#include "ext4_jbd2.h"
#include "group.h"
/*
* balloc.c contains the blocks allocation and deallocation routines
*/
/*
* Calculate the block group number and offset, given a block number
*/
void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
{
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
ext4_grpblk_t offset;
blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));
if (offsetp)
*offsetp = offset;
if (blockgrpp)
*blockgrpp = blocknr;
}
static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
ext4_group_t block_group)
{
ext4_group_t actual_group;
ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
if (actual_group == block_group)
return 1;
return 0;
}
static int ext4_group_used_meta_blocks(struct super_block *sb,
ext4_group_t block_group)
{
ext4_fsblk_t tmp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
/* block bitmap, inode bitmap, and inode table blocks */
int used_blocks = sbi->s_itb_per_group + 2;
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
struct ext4_group_desc *gdp;
struct buffer_head *bh;
gdp = ext4_get_group_desc(sb, block_group, &bh);
if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
block_group))
used_blocks--;
if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
block_group))
used_blocks--;
tmp = ext4_inode_table(sb, gdp);
for (; tmp < ext4_inode_table(sb, gdp) +
sbi->s_itb_per_group; tmp++) {
if (!ext4_block_in_group(sb, tmp, block_group))
used_blocks -= 1;
}
}
return used_blocks;
}
/* Initializes an uninitialized block bitmap if given, and returns the
* number of blocks free in the group. */
unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
ext4_group_t block_group, struct ext4_group_desc *gdp)
{
int bit, bit_max;
unsigned free_blocks, group_blocks;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (bh) {
J_ASSERT_BH(bh, buffer_locked(bh));
/* If checksum is bad mark all blocks used to prevent allocation
* essentially implementing a per-group read-only flag. */
if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
ext4_error(sb, __func__,
"Checksum bad for group %lu\n", block_group);
gdp->bg_free_blocks_count = 0;
gdp->bg_free_inodes_count = 0;
gdp->bg_itable_unused = 0;
memset(bh->b_data, 0xff, sb->s_blocksize);
return 0;
}
memset(bh->b_data, 0, sb->s_blocksize);
}
/* Check for superblock and gdt backups in this group */
bit_max = ext4_bg_has_super(sb, block_group);
if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
sbi->s_desc_per_block) {
if (bit_max) {
bit_max += ext4_bg_num_gdb(sb, block_group);
bit_max +=
le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
}
} else { /* For META_BG_BLOCK_GROUPS */
bit_max += ext4_bg_num_gdb(sb, block_group);
}
if (block_group == sbi->s_groups_count - 1) {
/*
* Even though mke2fs always initialize first and last group
* if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need
* to make sure we calculate the right free blocks
*/
group_blocks = ext4_blocks_count(sbi->s_es) -
le32_to_cpu(sbi->s_es->s_first_data_block) -
(EXT4_BLOCKS_PER_GROUP(sb) * (sbi->s_groups_count - 1));
} else {
group_blocks = EXT4_BLOCKS_PER_GROUP(sb);
}
free_blocks = group_blocks - bit_max;
if (bh) {
ext4_fsblk_t start, tmp;
int flex_bg = 0;
for (bit = 0; bit < bit_max; bit++)
ext4_set_bit(bit, bh->b_data);
start = ext4_group_first_block_no(sb, block_group);
if (EXT4_HAS_INCOMPAT_FEATURE(sb,
EXT4_FEATURE_INCOMPAT_FLEX_BG))
flex_bg = 1;
/* Set bits for block and inode bitmaps, and inode table */
tmp = ext4_block_bitmap(sb, gdp);
if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(tmp - start, bh->b_data);
tmp = ext4_inode_bitmap(sb, gdp);
if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(tmp - start, bh->b_data);
tmp = ext4_inode_table(sb, gdp);
for (; tmp < ext4_inode_table(sb, gdp) +
sbi->s_itb_per_group; tmp++) {
if (!flex_bg ||
ext4_block_in_group(sb, tmp, block_group))
ext4_set_bit(tmp - start, bh->b_data);
}
/*
* Also if the number of blocks within the group is
* less than the blocksize * 8 ( which is the size
* of bitmap ), set rest of the block bitmap to 1
*/
mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
}
return free_blocks - ext4_group_used_meta_blocks(sb, block_group);
}
/*
* 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 ext4_fill_super).
*/
#define in_range(b, first, len) ((b) >= (first) && (b) <= (first) + (len) - 1)
/**
* ext4_get_group_desc() -- load group descriptor from disk
* @sb: super block
* @block_group: given block group
* @bh: pointer to the buffer head to store the block
* group descriptor
*/
struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
ext4_group_t block_group,
struct buffer_head **bh)
{
unsigned long group_desc;
unsigned long offset;
struct ext4_group_desc *desc;
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (block_group >= sbi->s_groups_count) {
ext4_error(sb, "ext4_get_group_desc",
"block_group >= groups_count - "
"block_group = %lu, groups_count = %lu",
block_group, sbi->s_groups_count);
return NULL;
}
smp_rmb();
group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
if (!sbi->s_group_desc[group_desc]) {
ext4_error(sb, "ext4_get_group_desc",
"Group descriptor not loaded - "
"block_group = %lu, group_desc = %lu, desc = %lu",
block_group, group_desc, offset);
return NULL;
}
desc = (struct ext4_group_desc *)(
(__u8 *)sbi->s_group_desc[group_desc]->b_data +
offset * EXT4_DESC_SIZE(sb));
if (bh)
*bh = sbi->s_group_desc[group_desc];
return desc;
}
static int ext4_valid_block_bitmap(struct super_block *sb,
struct ext4_group_desc *desc,
unsigned int block_group,
struct buffer_head *bh)
{
ext4_grpblk_t offset;
ext4_grpblk_t next_zero_bit;
ext4_fsblk_t bitmap_blk;
ext4_fsblk_t group_first_block;
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
/* with FLEX_BG, the inode/block bitmaps and itable
* blocks may not be in the group at all
* so the bitmap validation will be skipped for those groups
* or it has to also read the block group where the bitmaps
* are located to verify they are set.
*/
return 1;
}
group_first_block = ext4_group_first_block_no(sb, block_group);
/* check whether block bitmap block number is set */
bitmap_blk = ext4_block_bitmap(sb, desc);
offset = bitmap_blk - group_first_block;
if (!ext4_test_bit(offset, bh->b_data))
/* bad block bitmap */
goto err_out;
/* check whether the inode bitmap block number is set */
bitmap_blk = ext4_inode_bitmap(sb, desc);
offset = bitmap_blk - group_first_block;
if (!ext4_test_bit(offset, bh->b_data))
/* bad block bitmap */
goto err_out;
/* check whether the inode table block number is set */
bitmap_blk = ext4_inode_table(sb, desc);
offset = bitmap_blk - group_first_block;
next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
offset + EXT4_SB(sb)->s_itb_per_group,
offset);
if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group)
/* good bitmap for inode tables */
return 1;
err_out:
ext4_error(sb, __func__,
"Invalid block bitmap - "
"block_group = %d, block = %llu",
block_group, bitmap_blk);
return 0;
}
/**
* ext4_read_block_bitmap()
* @sb: super block
* @block_group: given block group
*
* Read the bitmap for a given block_group,and validate the
* bits for block/inode/inode tables are set in the bitmaps
*
* Return buffer_head on success or NULL in case of failure.
*/
struct buffer_head *
ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
{
struct ext4_group_desc *desc;
struct buffer_head *bh = NULL;
ext4_fsblk_t bitmap_blk;
desc = ext4_get_group_desc(sb, block_group, NULL);
if (!desc)
return NULL;
bitmap_blk = ext4_block_bitmap(sb, desc);
bh = sb_getblk(sb, bitmap_blk);
if (unlikely(!bh)) {
ext4_error(sb, __func__,
"Cannot read block bitmap - "
"block_group = %lu, block_bitmap = %llu",
block_group, bitmap_blk);
return NULL;
}
if (buffer_uptodate(bh) &&
!(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))
return bh;
lock_buffer(bh);
spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
ext4_init_block_bitmap(sb, bh, block_group, desc);
set_buffer_uptodate(bh);
unlock_buffer(bh);
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
return bh;
}
spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
if (bh_submit_read(bh) < 0) {
put_bh(bh);
ext4_error(sb, __func__,
"Cannot read block bitmap - "
"block_group = %lu, block_bitmap = %llu",
block_group, bitmap_blk);
return NULL;
}
ext4_valid_block_bitmap(sb, desc, block_group, bh);
/*
* file system mounted not to panic on error,
* continue with corrupt bitmap
*/
return bh;
}
/**
* ext4_free_blocks_sb() -- Free given blocks and update quota
* @handle: handle to this transaction
* @sb: super block
* @block: start physcial block to free
* @count: number of blocks to free
* @pdquot_freed_blocks: pointer to quota
*
* XXX This function is only used by the on-line resizing code, which
* should probably be fixed up to call the mballoc variant. There
* this needs to be cleaned up later; in fact, I'm not convinced this
* is 100% correct in the face of the mballoc code. The online resizing
* code needs to be fixed up to more tightly (and correctly) interlock
* with the mballoc code.
*/
void ext4_free_blocks_sb(handle_t *handle, struct super_block *sb,
ext4_fsblk_t block, unsigned long count,
unsigned long *pdquot_freed_blocks)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gd_bh;
ext4_group_t block_group;
ext4_grpblk_t bit;
unsigned long i;
unsigned long overflow;
struct ext4_group_desc *desc;
struct ext4_super_block *es;
struct ext4_sb_info *sbi;
int err = 0, ret;
ext4_grpblk_t group_freed;
*pdquot_freed_blocks = 0;
sbi = EXT4_SB(sb);
es = sbi->s_es;
if (block < le32_to_cpu(es->s_first_data_block) ||
block + count < block ||
block + count > ext4_blocks_count(es)) {
ext4_error(sb, "ext4_free_blocks",
"Freeing blocks not in datazone - "
"block = %llu, count = %lu", block, count);
goto error_return;
}
ext4_debug("freeing block(s) %llu-%llu\n", block, block + count - 1);
do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb);
count -= overflow;
}
brelse(bitmap_bh);
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (!bitmap_bh)
goto error_return;
desc = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!desc)
goto error_return;
if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
in_range(ext4_inode_bitmap(sb, desc), block, count) ||
in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, desc),
sbi->s_itb_per_group)) {
ext4_error(sb, "ext4_free_blocks",
"Freeing blocks in system zones - "
"Block = %llu, count = %lu",
block, count);
goto error_return;
}
/*
* 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 = ext4_journal_get_undo_access(handle, bitmap_bh);
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 = ext4_journal_get_write_access(handle, gd_bh);
if (err)
goto error_return;
jbd_lock_bh_state(bitmap_bh);
for (i = 0, group_freed = 0; i < count; i++) {
/*
* An HJ special. This is expensive...
*/
#ifdef CONFIG_JBD2_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
if (need_resched()) {
jbd_unlock_bh_state(bitmap_bh);
cond_resched();
jbd_lock_bh_state(bitmap_bh);
}
/* @@@ 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 jbd2_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 jbd2_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);
ext4_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 (!ext4_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
bit + i, bitmap_bh->b_data)) {
jbd_unlock_bh_state(bitmap_bh);
ext4_error(sb, __func__,
"bit already cleared for block %llu",
(ext4_fsblk_t)(block + i));
jbd_lock_bh_state(bitmap_bh);
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
group_freed++;
}
}
jbd_unlock_bh_state(bitmap_bh);
spin_lock(sb_bgl_lock(sbi, block_group));
le16_add_cpu(&desc->bg_free_blocks_count, group_freed);
desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
spin_unlock(sb_bgl_lock(sbi, block_group));
percpu_counter_add(&sbi->s_freeblocks_counter, count);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
spin_lock(sb_bgl_lock(sbi, flex_group));
sbi->s_flex_groups[flex_group].free_blocks += count;
spin_unlock(sb_bgl_lock(sbi, flex_group));
}
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_journal_dirty_metadata(handle, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_journal_dirty_metadata(handle, gd_bh);
if (!err) err = ret;
*pdquot_freed_blocks += group_freed;
if (overflow && !err) {
block += count;
count = overflow;
goto do_more;
}
sb->s_dirt = 1;
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
return;
}
/**
* ext4_free_blocks() -- Free given blocks and update quota
* @handle: handle for this transaction
* @inode: inode
* @block: start physical block to free
* @count: number of blocks to count
* @metadata: Are these metadata blocks
*/
void ext4_free_blocks(handle_t *handle, struct inode *inode,
ext4_fsblk_t block, unsigned long count,
int metadata)
{
struct super_block *sb;
unsigned long dquot_freed_blocks;
/* this isn't the right place to decide whether block is metadata
* inode.c/extents.c knows better, but for safety ... */
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
ext4_should_journal_data(inode))
metadata = 1;
sb = inode->i_sb;
ext4_mb_free_blocks(handle, inode, block, count,
metadata, &dquot_freed_blocks);
if (dquot_freed_blocks)
DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
return;
}
int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
s64 nblocks)
{
s64 free_blocks, dirty_blocks;
s64 root_blocks = 0;
struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
free_blocks = percpu_counter_read_positive(fbc);
dirty_blocks = percpu_counter_read_positive(dbc);
if (!capable(CAP_SYS_RESOURCE) &&
sbi->s_resuid != current->fsuid &&
(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
root_blocks = ext4_r_blocks_count(sbi->s_es);
if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
EXT4_FREEBLOCKS_WATERMARK) {
free_blocks = percpu_counter_sum(fbc);
dirty_blocks = percpu_counter_sum(dbc);
if (dirty_blocks < 0) {
printk(KERN_CRIT "Dirty block accounting "
"went wrong %lld\n",
dirty_blocks);
}
}
/* Check whether we have space after
* accounting for current dirty blocks
*/
if (free_blocks < ((root_blocks + nblocks) + dirty_blocks))
/* we don't have free space */
return -ENOSPC;
/* Add the blocks to nblocks */
percpu_counter_add(dbc, nblocks);
return 0;
}
/**
* ext4_has_free_blocks()
* @sbi: in-core super block structure.
* @nblocks: number of neeed blocks
*
* Check if filesystem has free blocks available for allocation.
* Return the number of blocks avaible for allocation for this request
* On success, return nblocks
*/
ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
s64 nblocks)
{
s64 free_blocks, dirty_blocks;
s64 root_blocks = 0;
struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
free_blocks = percpu_counter_read_positive(fbc);
dirty_blocks = percpu_counter_read_positive(dbc);
if (!capable(CAP_SYS_RESOURCE) &&
sbi->s_resuid != current->fsuid &&
(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
root_blocks = ext4_r_blocks_count(sbi->s_es);
if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
EXT4_FREEBLOCKS_WATERMARK) {
free_blocks = percpu_counter_sum(fbc);
dirty_blocks = percpu_counter_sum(dbc);
}
if (free_blocks <= (root_blocks + dirty_blocks))
/* we don't have free space */
return 0;
if (free_blocks - (root_blocks + dirty_blocks) < nblocks)
return free_blocks - (root_blocks + dirty_blocks);
return nblocks;
}
/**
* ext4_should_retry_alloc()
* @sb: super block
* @retries number of attemps has been made
*
* ext4_should_retry_alloc() is called when ENOSPC is returned, and if
* it is profitable to retry the operation, this function will wait
* for the current or commiting transaction to complete, and then
* return TRUE.
*
* if the total number of retries exceed three times, return FALSE.
*/
int ext4_should_retry_alloc(struct super_block *sb, int *retries)
{
if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || (*retries)++ > 3)
return 0;
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
}
#define EXT4_META_BLOCK 0x1
static ext4_fsblk_t do_blk_alloc(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock, ext4_fsblk_t goal,
unsigned long *count, int *errp, int flags)
{
struct ext4_allocation_request ar;
ext4_fsblk_t ret;
memset(&ar, 0, sizeof(ar));
/* Fill with neighbour allocated blocks */
ar.inode = inode;
ar.goal = goal;
ar.len = *count;
ar.logical = iblock;
if (S_ISREG(inode->i_mode) && !(flags & EXT4_META_BLOCK))
/* enable in-core preallocation for data block allocation */
ar.flags = EXT4_MB_HINT_DATA;
else
/* disable in-core preallocation for non-regular files */
ar.flags = 0;
ret = ext4_mb_new_blocks(handle, &ar, errp);
*count = ar.len;
return ret;
}
/*
* ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
*
* @handle: handle to this transaction
* @inode: file inode
* @goal: given target block(filesystem wide)
* @count: total number of blocks need
* @errp: error code
*
* Return 1st allocated block numberon success, *count stores total account
* error stores in errp pointer
*/
ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
ext4_fsblk_t goal, unsigned long *count, int *errp)
{
ext4_fsblk_t ret;
ret = do_blk_alloc(handle, inode, 0, goal,
count, errp, EXT4_META_BLOCK);
/*
* Account for the allocated meta blocks
*/
if (!(*errp) && EXT4_I(inode)->i_delalloc_reserved_flag) {
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
EXT4_I(inode)->i_allocated_meta_blocks += *count;
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
}
return ret;
}
/*
* ext4_new_meta_block() -- allocate block for meta data (indexing) blocks
*
* @handle: handle to this transaction
* @inode: file inode
* @goal: given target block(filesystem wide)
* @errp: error code
*
* Return allocated block number on success
*/
ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
ext4_fsblk_t goal, int *errp)
{
unsigned long count = 1;
return ext4_new_meta_blocks(handle, inode, goal, &count, errp);
}
/*
* ext4_new_blocks() -- allocate data blocks
*
* @handle: handle to this transaction
* @inode: file inode
* @goal: given target block(filesystem wide)
* @count: total number of blocks need
* @errp: error code
*
* Return 1st allocated block numberon success, *count stores total account
* error stores in errp pointer
*/
ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
ext4_lblk_t iblock, ext4_fsblk_t goal,
unsigned long *count, int *errp)
{
return do_blk_alloc(handle, inode, iblock, goal, count, errp, 0);
}
/**
* ext4_count_free_blocks() -- count filesystem free blocks
* @sb: superblock
*
* Adds up the number of free blocks from each block group.
*/
ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
{
ext4_fsblk_t desc_count;
struct ext4_group_desc *gdp;
ext4_group_t i;
ext4_group_t ngroups = EXT4_SB(sb)->s_groups_count;
#ifdef EXT4FS_DEBUG
struct ext4_super_block *es;
ext4_fsblk_t bitmap_count;
unsigned long x;
struct buffer_head *bitmap_bh = NULL;
es = EXT4_SB(sb)->s_es;
desc_count = 0;
bitmap_count = 0;
gdp = NULL;
smp_rmb();
for (i = 0; i < ngroups; i++) {
gdp = ext4_get_group_desc(sb, i, NULL);
if (!gdp)
continue;
desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
brelse(bitmap_bh);
bitmap_bh = ext4_read_block_bitmap(sb, i);
if (bitmap_bh == NULL)
continue;
x = ext4_count_free(bitmap_bh, sb->s_blocksize);
printk(KERN_DEBUG "group %lu: stored = %d, counted = %lu\n",
i, le16_to_cpu(gdp->bg_free_blocks_count), x);
bitmap_count += x;
}
brelse(bitmap_bh);
printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu"
", computed = %llu, %llu\n", ext4_free_blocks_count(es),
desc_count, bitmap_count);
return bitmap_count;
#else
desc_count = 0;
smp_rmb();
for (i = 0; i < ngroups; i++) {
gdp = ext4_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 test_root(ext4_group_t a, int b)
{
int num = b;
while (a > num)
num *= b;
return num == a;
}
static int ext4_group_sparse(ext4_group_t group)
{
if (group <= 1)
return 1;
if (!(group & 1))
return 0;
return (test_root(group, 7) || test_root(group, 5) ||
test_root(group, 3));
}
/**
* ext4_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 ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
{
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
!ext4_group_sparse(group))
return 0;
return 1;
}
static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
ext4_group_t group)
{
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
if (group == first || group == first + 1 || group == last)
return 1;
return 0;
}
static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
ext4_group_t group)
{
return ext4_bg_has_super(sb, group) ? EXT4_SB(sb)->s_gdb_count : 0;
}
/**
* ext4_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 ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
{
unsigned long first_meta_bg =
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
metagroup < first_meta_bg)
return ext4_bg_num_gdb_nometa(sb, group);
return ext4_bg_num_gdb_meta(sb,group);
}