- 根目录:
- fs
- ext4
- migrate.c
/*
* Copyright IBM Corporation, 2007
* Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <linux/module.h>
#include <linux/slab.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"
/*
* The contiguous blocks details which can be
* represented by a single extent
*/
struct list_blocks_struct {
ext4_lblk_t first_block, last_block;
ext4_fsblk_t first_pblock, last_pblock;
};
static int finish_range(handle_t *handle, struct inode *inode,
struct list_blocks_struct *lb)
{
int retval = 0, needed;
struct ext4_extent newext;
struct ext4_ext_path *path;
if (lb->first_pblock == 0)
return 0;
/* Add the extent to temp inode*/
newext.ee_block = cpu_to_le32(lb->first_block);
newext.ee_len = cpu_to_le16(lb->last_block - lb->first_block + 1);
ext4_ext_store_pblock(&newext, lb->first_pblock);
path = ext4_ext_find_extent(inode, lb->first_block, NULL);
if (IS_ERR(path)) {
retval = PTR_ERR(path);
path = NULL;
goto err_out;
}
/*
* Calculate the credit needed to inserting this extent
* Since we are doing this in loop we may accumalate extra
* credit. But below we try to not accumalate too much
* of them by restarting the journal.
*/
needed = ext4_ext_calc_credits_for_single_extent(inode,
lb->last_block - lb->first_block + 1, path);
/*
* Make sure the credit we accumalated is not really high
*/
if (needed && ext4_handle_has_enough_credits(handle,
EXT4_RESERVE_TRANS_BLOCKS)) {
retval = ext4_journal_restart(handle, needed);
if (retval)
goto err_out;
} else if (needed) {
retval = ext4_journal_extend(handle, needed);
if (retval) {
/*
* IF not able to extend the journal restart the journal
*/
retval = ext4_journal_restart(handle, needed);
if (retval)
goto err_out;
}
}
retval = ext4_ext_insert_extent(handle, inode, path, &newext, 0);
err_out:
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
lb->first_pblock = 0;
return retval;
}
static int update_extent_range(handle_t *handle, struct inode *inode,
ext4_fsblk_t pblock, ext4_lblk_t blk_num,
struct list_blocks_struct *lb)
{
int retval;
/*
* See if we can add on to the existing range (if it exists)
*/
if (lb->first_pblock &&
(lb->last_pblock+1 == pblock) &&
(lb->last_block+1 == blk_num)) {
lb->last_pblock = pblock;
lb->last_block = blk_num;
return 0;
}
/*
* Start a new range.
*/
retval = finish_range(handle, inode, lb);
lb->first_pblock = lb->last_pblock = pblock;
lb->first_block = lb->last_block = blk_num;
return retval;
}
static int update_ind_extent_range(handle_t *handle, struct inode *inode,
ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
struct list_blocks_struct *lb)
{
struct buffer_head *bh;
__le32 *i_data;
int i, retval = 0;
ext4_lblk_t blk_count = *blk_nump;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
if (!pblock) {
/* Only update the file block number */
*blk_nump += max_entries;
return 0;
}
bh = sb_bread(inode->i_sb, pblock);
if (!bh)
return -EIO;
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++, blk_count++) {
if (i_data[i]) {
retval = update_extent_range(handle, inode,
le32_to_cpu(i_data[i]),
blk_count, lb);
if (retval)
break;
}
}
/* Update the file block number */
*blk_nump = blk_count;
put_bh(bh);
return retval;
}
static int update_dind_extent_range(handle_t *handle, struct inode *inode,
ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
struct list_blocks_struct *lb)
{
struct buffer_head *bh;
__le32 *i_data;
int i, retval = 0;
ext4_lblk_t blk_count = *blk_nump;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
if (!pblock) {
/* Only update the file block number */
*blk_nump += max_entries * max_entries;
return 0;
}
bh = sb_bread(inode->i_sb, pblock);
if (!bh)
return -EIO;
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
if (i_data[i]) {
retval = update_ind_extent_range(handle, inode,
le32_to_cpu(i_data[i]),
&blk_count, lb);
if (retval)
break;
} else {
/* Only update the file block number */
blk_count += max_entries;
}
}
/* Update the file block number */
*blk_nump = blk_count;
put_bh(bh);
return retval;
}
static int update_tind_extent_range(handle_t *handle, struct inode *inode,
ext4_fsblk_t pblock, ext4_lblk_t *blk_nump,
struct list_blocks_struct *lb)
{
struct buffer_head *bh;
__le32 *i_data;
int i, retval = 0;
ext4_lblk_t blk_count = *blk_nump;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
if (!pblock) {
/* Only update the file block number */
*blk_nump += max_entries * max_entries * max_entries;
return 0;
}
bh = sb_bread(inode->i_sb, pblock);
if (!bh)
return -EIO;
i_data = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
if (i_data[i]) {
retval = update_dind_extent_range(handle, inode,
le32_to_cpu(i_data[i]),
&blk_count, lb);
if (retval)
break;
} else
/* Only update the file block number */
blk_count += max_entries * max_entries;
}
/* Update the file block number */
*blk_nump = blk_count;
put_bh(bh);
return retval;
}
static int extend_credit_for_blkdel(handle_t *handle, struct inode *inode)
{
int retval = 0, needed;
if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
return 0;
/*
* We are freeing a blocks. During this we touch
* superblock, group descriptor and block bitmap.
* So allocate a credit of 3. We may update
* quota (user and group).
*/
needed = 3 + EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
if (ext4_journal_extend(handle, needed) != 0)
retval = ext4_journal_restart(handle, needed);
return retval;
}
static int free_dind_blocks(handle_t *handle,
struct inode *inode, __le32 i_data)
{
int i;
__le32 *tmp_idata;
struct buffer_head *bh;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
if (!bh)
return -EIO;
tmp_idata = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
if (tmp_idata[i]) {
extend_credit_for_blkdel(handle, inode);
ext4_free_blocks(handle, inode, NULL,
le32_to_cpu(tmp_idata[i]), 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
}
}
put_bh(bh);
extend_credit_for_blkdel(handle, inode);
ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
return 0;
}
static int free_tind_blocks(handle_t *handle,
struct inode *inode, __le32 i_data)
{
int i, retval = 0;
__le32 *tmp_idata;
struct buffer_head *bh;
unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
bh = sb_bread(inode->i_sb, le32_to_cpu(i_data));
if (!bh)
return -EIO;
tmp_idata = (__le32 *)bh->b_data;
for (i = 0; i < max_entries; i++) {
if (tmp_idata[i]) {
retval = free_dind_blocks(handle,
inode, tmp_idata[i]);
if (retval) {
put_bh(bh);
return retval;
}
}
}
put_bh(bh);
extend_credit_for_blkdel(handle, inode);
ext4_free_blocks(handle, inode, NULL, le32_to_cpu(i_data), 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
return 0;
}
static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
{
int retval;
/* ei->i_data[EXT4_IND_BLOCK] */
if (i_data[0]) {
extend_credit_for_blkdel(handle, inode);
ext4_free_blocks(handle, inode, NULL,
le32_to_cpu(i_data[0]), 1,
EXT4_FREE_BLOCKS_METADATA |
EXT4_FREE_BLOCKS_FORGET);
}
/* ei->i_data[EXT4_DIND_BLOCK] */
if (i_data[1]) {
retval = free_dind_blocks(handle, inode, i_data[1]);
if (retval)
return retval;
}
/* ei->i_data[EXT4_TIND_BLOCK] */
if (i_data[2]) {
retval = free_tind_blocks(handle, inode, i_data[2]);
if (retval)
return retval;
}
return 0;
}
static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
struct inode *tmp_inode)
{
int retval;
__le32 i_data[3];
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
/*
* One credit accounted for writing the
* i_data field of the original inode
*/
retval = ext4_journal_extend(handle, 1);
if (retval) {
retval = ext4_journal_restart(handle, 1);
if (retval)
goto err_out;
}
i_data[0] = ei->i_data[EXT4_IND_BLOCK];
i_data[1] = ei->i_data[EXT4_DIND_BLOCK];
i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
down_write(&EXT4_I(inode)->i_data_sem);
/*
* if EXT4_STATE_EXT_MIGRATE is cleared a block allocation
* happened after we started the migrate. We need to
* fail the migrate
*/
if (!ext4_test_inode_state(inode, EXT4_STATE_EXT_MIGRATE)) {
retval = -EAGAIN;
up_write(&EXT4_I(inode)->i_data_sem);
goto err_out;
} else
ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
/*
* We have the extent map build with the tmp inode.
* Now copy the i_data across
*/
ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
memcpy(ei->i_data, tmp_ei->i_data, sizeof(ei->i_data));
/*
* Update i_blocks with the new blocks that got
* allocated while adding extents for extent index
* blocks.
*
* While converting to extents we need not
* update the orignal inode i_blocks for extent blocks
* via quota APIs. The quota update happened via tmp_inode already.
*/
spin_lock(&inode->i_lock);
inode->i_blocks += tmp_inode->i_blocks;
spin_unlock(&inode->i_lock);
up_write(&EXT4_I(inode)->i_data_sem);
/*
* We mark the inode dirty after, because we decrement the
* i_blocks when freeing the indirect meta-data blocks
*/
retval = free_ind_block(handle, inode, i_data);
ext4_mark_inode_dirty(handle, inode);
err_out:
return retval;
}
static int free_ext_idx(handle_t *handle, struct inode *inode,
struct ext4_extent_idx *ix)
{
int i, retval = 0;
ext4_fsblk_t block;
struct buffer_head *bh;
struct ext4_extent_header *eh;
block = ext4_idx_pblock(ix);
bh = sb_bread(inode->i_sb, block);
if (!bh)
return -EIO;
eh = (struct ext4_extent_header *)bh->b_data;
if (eh->eh_depth != 0) {
ix = EXT_FIRST_INDEX(eh);
for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
retval = free_ext_idx(handle, inode, ix);
if (retval)
break;
}
}
put_bh(bh);
extend_credit_for_blkdel(handle, inode);
ext4_free_blocks(handle, inode, NULL, block, 1,
EXT4_FREE_BLOCKS_METADATA | EXT4_FREE_BLOCKS_FORGET);
return retval;
}
/*
* Free the extent meta data blocks only
*/
static int free_ext_block(handle_t *handle, struct inode *inode)
{
int i, retval = 0;
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_extent_header *eh = (struct ext4_extent_header *)ei->i_data;
struct ext4_extent_idx *ix;
if (eh->eh_depth == 0)
/*
* No extra blocks allocated for extent meta data
*/
return 0;
ix = EXT_FIRST_INDEX(eh);
for (i = 0; i < le16_to_cpu(eh->eh_entries); i++, ix++) {
retval = free_ext_idx(handle, inode, ix);
if (retval)
return retval;
}
return retval;
}
int ext4_ext_migrate(struct inode *inode)
{
handle_t *handle;
int retval = 0, i;
__le32 *i_data;
ext4_lblk_t blk_count = 0;
struct ext4_inode_info *ei;
struct inode *tmp_inode = NULL;
struct list_blocks_struct lb;
unsigned long max_entries;
__u32 goal;
/*
* If the filesystem does not support extents, or the inode
* already is extent-based, error out.
*/
if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
EXT4_FEATURE_INCOMPAT_EXTENTS) ||
(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return -EINVAL;
if (S_ISLNK(inode->i_mode) && inode->i_blocks == 0)
/*
* don't migrate fast symlink
*/
return retval;
handle = ext4_journal_start(inode,
EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
EXT4_MAXQUOTAS_INIT_BLOCKS(inode->i_sb)
+ 1);
if (IS_ERR(handle)) {
retval = PTR_ERR(handle);
return retval;
}
goal = (((inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb)) *
EXT4_INODES_PER_GROUP(inode->i_sb)) + 1;
tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
S_IFREG, NULL, goal);
if (IS_ERR(tmp_inode)) {
retval = -ENOMEM;
ext4_journal_stop(handle);
return retval;
}
i_size_write(tmp_inode, i_size_read(inode));
/*
* Set the i_nlink to zero so it will be deleted later
* when we drop inode reference.
*/
tmp_inode->i_nlink = 0;
ext4_ext_tree_init(handle, tmp_inode);
ext4_orphan_add(handle, tmp_inode);
ext4_journal_stop(handle);
/*
* start with one credit accounted for
* superblock modification.
*
* For the tmp_inode we already have committed the
* trascation that created the inode. Later as and
* when we add extents we extent the journal
*/
/*
* Even though we take i_mutex we can still cause block
* allocation via mmap write to holes. If we have allocated
* new blocks we fail migrate. New block allocation will
* clear EXT4_STATE_EXT_MIGRATE flag. The flag is updated
* with i_data_sem held to prevent racing with block
* allocation.
*/
down_read((&EXT4_I(inode)->i_data_sem));
ext4_set_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
up_read((&EXT4_I(inode)->i_data_sem));
handle = ext4_journal_start(inode, 1);
if (IS_ERR(handle)) {
/*
* It is impossible to update on-disk structures without
* a handle, so just rollback in-core changes and live other
* work to orphan_list_cleanup()
*/
ext4_orphan_del(NULL, tmp_inode);
retval = PTR_ERR(handle);
goto out;
}
ei = EXT4_I(inode);
i_data = ei->i_data;
memset(&lb, 0, sizeof(lb));
/* 32 bit block address 4 bytes */
max_entries = inode->i_sb->s_blocksize >> 2;
for (i = 0; i < EXT4_NDIR_BLOCKS; i++, blk_count++) {
if (i_data[i]) {
retval = update_extent_range(handle, tmp_inode,
le32_to_cpu(i_data[i]),
blk_count, &lb);
if (retval)
goto err_out;
}
}
if (i_data[EXT4_IND_BLOCK]) {
retval = update_ind_extent_range(handle, tmp_inode,
le32_to_cpu(i_data[EXT4_IND_BLOCK]),
&blk_count, &lb);
if (retval)
goto err_out;
} else
blk_count += max_entries;
if (i_data[EXT4_DIND_BLOCK]) {
retval = update_dind_extent_range(handle, tmp_inode,
le32_to_cpu(i_data[EXT4_DIND_BLOCK]),
&blk_count, &lb);
if (retval)
goto err_out;
} else
blk_count += max_entries * max_entries;
if (i_data[EXT4_TIND_BLOCK]) {
retval = update_tind_extent_range(handle, tmp_inode,
le32_to_cpu(i_data[EXT4_TIND_BLOCK]),
&blk_count, &lb);
if (retval)
goto err_out;
}
/*
* Build the last extent
*/
retval = finish_range(handle, tmp_inode, &lb);
err_out:
if (retval)
/*
* Failure case delete the extent information with the
* tmp_inode
*/
free_ext_block(handle, tmp_inode);
else {
retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
if (retval)
/*
* if we fail to swap inode data free the extent
* details of the tmp inode
*/
free_ext_block(handle, tmp_inode);
}
/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
if (ext4_journal_extend(handle, 1) != 0)
ext4_journal_restart(handle, 1);
/*
* Mark the tmp_inode as of size zero
*/
i_size_write(tmp_inode, 0);
/*
* set the i_blocks count to zero
* so that the ext4_delete_inode does the
* right job
*
* We don't need to take the i_lock because
* the inode is not visible to user space.
*/
tmp_inode->i_blocks = 0;
/* Reset the extent details */
ext4_ext_tree_init(handle, tmp_inode);
ext4_journal_stop(handle);
out:
unlock_new_inode(tmp_inode);
iput(tmp_inode);
return retval;
}