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-rw-r--r--fs/ext4/migrate.c604
1 files changed, 604 insertions, 0 deletions
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
new file mode 100644
index 00000000..f39f80f8
--- /dev/null
+++ b/fs/ext4/migrate.c
@@ -0,0 +1,604 @@
+/*
+ * 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/slab.h>
+#include "ext4_jbd2.h"
+
+/*
+ * The contiguous blocks details which can be
+ * represented by a single extent
+ */
+struct migrate_struct {
+ ext4_lblk_t first_block, last_block, curr_block;
+ ext4_fsblk_t first_pblock, last_pblock;
+};
+
+static int finish_range(handle_t *handle, struct inode *inode,
+ struct migrate_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, struct migrate_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 == lb->curr_block)) {
+ lb->last_pblock = pblock;
+ lb->last_block = lb->curr_block;
+ lb->curr_block++;
+ 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 = lb->curr_block;
+ lb->curr_block++;
+ return retval;
+}
+
+static int update_ind_extent_range(handle_t *handle, struct inode *inode,
+ ext4_fsblk_t pblock,
+ struct migrate_struct *lb)
+{
+ struct buffer_head *bh;
+ __le32 *i_data;
+ int i, retval = 0;
+ unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+ 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_extent_range(handle, inode,
+ le32_to_cpu(i_data[i]), lb);
+ if (retval)
+ break;
+ } else {
+ lb->curr_block++;
+ }
+ }
+ put_bh(bh);
+ return retval;
+
+}
+
+static int update_dind_extent_range(handle_t *handle, struct inode *inode,
+ ext4_fsblk_t pblock,
+ struct migrate_struct *lb)
+{
+ struct buffer_head *bh;
+ __le32 *i_data;
+ int i, retval = 0;
+ unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+ 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]), lb);
+ if (retval)
+ break;
+ } else {
+ /* Only update the file block number */
+ lb->curr_block += max_entries;
+ }
+ }
+ put_bh(bh);
+ return retval;
+
+}
+
+static int update_tind_extent_range(handle_t *handle, struct inode *inode,
+ ext4_fsblk_t pblock,
+ struct migrate_struct *lb)
+{
+ struct buffer_head *bh;
+ __le32 *i_data;
+ int i, retval = 0;
+ unsigned long max_entries = inode->i_sb->s_blocksize >> 2;
+
+ 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]), lb);
+ if (retval)
+ break;
+ } else {
+ /* Only update the file block number */
+ lb->curr_block += max_entries * max_entries;
+ }
+ }
+ 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;
+ struct ext4_inode_info *ei;
+ struct inode *tmp_inode = NULL;
+ struct migrate_struct lb;
+ unsigned long max_entries;
+ __u32 goal;
+ uid_t owner[2];
+
+ /*
+ * 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;
+ owner[0] = inode->i_uid;
+ owner[1] = inode->i_gid;
+ tmp_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode,
+ S_IFREG, NULL, goal, owner);
+ if (IS_ERR(tmp_inode)) {
+ retval = PTR_ERR(tmp_inode);
+ 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.
+ */
+ clear_nlink(tmp_inode);
+
+ 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++) {
+ if (i_data[i]) {
+ retval = update_extent_range(handle, tmp_inode,
+ le32_to_cpu(i_data[i]), &lb);
+ if (retval)
+ goto err_out;
+ } else
+ lb.curr_block++;
+ }
+ if (i_data[EXT4_IND_BLOCK]) {
+ retval = update_ind_extent_range(handle, tmp_inode,
+ le32_to_cpu(i_data[EXT4_IND_BLOCK]), &lb);
+ if (retval)
+ goto err_out;
+ } else
+ lb.curr_block += max_entries;
+ if (i_data[EXT4_DIND_BLOCK]) {
+ retval = update_dind_extent_range(handle, tmp_inode,
+ le32_to_cpu(i_data[EXT4_DIND_BLOCK]), &lb);
+ if (retval)
+ goto err_out;
+ } else
+ lb.curr_block += 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]), &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;
+}
generated by cgit (git 2.34.1) at 2024-12-23 05:02:10 +0000