Re: [PATCH 36/49] ext4: Add EXT4_IOC_MIGRATE ioctl

Aneesh Kumar K.V
2008-01-24T05:57:17Z

On Wed, Jan 23, 2008 at 02:07:16PM -0800, Andrew Morton wrote:
> > On Mon, 21 Jan 2008 22:02:15 -0500 "Theodore Ts'o" <tytso@MIT.EDU> wrote:
> > The below patch add ioctl for migrating ext3 indirect block mapped inode
> > to ext4 extent mapped inode.
>
> This patch adds lots of weird and inexplicable single- and double-newlines
> in inappropriate places. However it frequently forgets to add newlines
> between end-of-locals and start-of-code, which is usual practice.
>
>
> +struct list_blocks_struct {
> + ext4_lblk_t first_block, last_block;
> + ext4_fsblk_t first_pblock, last_pblock;
> +};
>

Updated patch

commit c4786b67cdc5b24d2548a69b62774fb54f8f1575
Author: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Tue Jan 22 09:28:55 2008 +0530

ext4: Add EXT4_IOC_MIGRATE ioctl

The below patch add ioctl for migrating ext3 indirect block mapped inode
to ext4 extent mapped inode.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index ae6e7e5..d5fd80b 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_EXT4DEV_FS) += ext4dev.o

ext4dev-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
- ext4_jbd2.o
+ ext4_jbd2.o migrate.o

ext4dev-$(CONFIG_EXT4DEV_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext4dev-$(CONFIG_EXT4DEV_FS_POSIX_ACL) += acl.o
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 03d1bbb..323cd76 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -75,7 +75,7 @@ static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
* stores a large physical block number into an extent struct,
* breaking it into parts
*/
-static void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
+void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
{
ex->ee_start_lo = cpu_to_le32((unsigned long) (pb & 0xffffffff));
ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index c0e5b8c..2ed7c37 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -254,6 +254,9 @@ flags_err:
return err;
}

+ case EXT4_IOC_MIGRATE:
+ return ext4_ext_migrate(inode, filp, cmd, arg);
+
default:
return -ENOTTY;
}
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
new file mode 100644
index 0000000..deb2327
--- /dev/null
+++ b/fs/ext4/migrate.c
@@ -0,0 +1,588 @@
+/*
+ * 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/ext4_jbd2.h>
+#include <linux/ext4_fs_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);
+ 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_insert(inode, path);
+
+ /*
+ * Make sure the credit we accumalated is not really high
+ */
+ if (needed && handle->h_buffer_credits >= EXT4_RESERVE_TRANS_BLOCKS) {
+
+ retval = ext4_journal_restart(handle, needed);
+ if (retval)
+ goto err_out;
+ }
+ if (needed) {
+ retval = ext4_journal_extend(handle, needed);
+ if (retval != 0) {
+ /*
+ * 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);
+
+err_out:
+ 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;
+ brelse(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;
+ brelse(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;
+ brelse(bh);
+ 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]) {
+ ext4_free_blocks(handle, inode,
+ le32_to_cpu(tmp_idata[i]), 1);
+ }
+ }
+ brelse(bh);
+ ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1);
+ 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) {
+ brelse(bh);
+ return retval;
+ }
+ }
+ }
+ brelse(bh);
+ ext4_free_blocks(handle, inode, le32_to_cpu(i_data), 1);
+ return 0;
+}
+
+static int free_ind_block(handle_t *handle, struct inode *inode)
+{
+ int retval;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ if (ei->i_data[EXT4_IND_BLOCK]) {
+ ext4_free_blocks(handle, inode,
+ le32_to_cpu(ei->i_data[EXT4_IND_BLOCK]), 1);
+ }
+
+ if (ei->i_data[EXT4_DIND_BLOCK]) {
+ retval = free_dind_blocks(handle, inode,
+ ei->i_data[EXT4_DIND_BLOCK]);
+ if (retval)
+ return retval;
+ }
+
+ if (ei->i_data[EXT4_TIND_BLOCK]) {
+ retval = free_tind_blocks(handle, inode,
+ ei->i_data[EXT4_TIND_BLOCK]);
+ 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)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct ext4_inode_info *tmp_ei = EXT4_I(tmp_inode);
+
+ retval = free_ind_block(handle, inode);
+ if (retval)
+ goto err_out;
+
+ /*
+ * One credit accounted for writing the
+ * i_data field of the original inode
+ */
+ retval = ext4_journal_extend(handle, 1);
+ if (retval != 0) {
+ retval = ext4_journal_restart(handle, 1);
+ if (retval)
+ goto err_out;
+ }
+
+ /*
+ * We have the extent map build with the tmp inode.
+ * Now copy the i_data across
+ */
+ ei->i_flags |= EXT4_EXTENTS_FL;
+ 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);
+
+ ext4_mark_inode_dirty(handle, inode);
+err_out:
+ return retval;
+}
+
+/* Will go away */
+static ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
+{
+ ext4_fsblk_t block;
+
+ block = le32_to_cpu(ix->ei_leaf_lo);
+ block |= ((ext4_fsblk_t) le16_to_cpu(ix->ei_leaf_hi) << 31) << 1;
+ return block;
+}
+
+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 = 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) {
+ brelse(bh);
+ ext4_free_blocks(handle, inode, block, 1);
+ } else {
+ 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;
+}
+
+/*
+ * 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, struct file *filp,
+ unsigned int cmd, unsigned long arg)
+{
+ 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;
+
+ if (!test_opt(inode->i_sb, EXTENTS)) {
+ /*
+ * if mounted with noextents
+ * we don't allow the migrate
+ */
+ return -EINVAL;
+ }
+
+ if ((EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ return -EINVAL;
+
+ down_write(&EXT4_I(inode)->i_data_sem);
+ handle = ext4_journal_start(inode,
+ EXT4_DATA_TRANS_BLOCKS(inode->i_sb) +
+ EXT4_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+ 2 * EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)
+ + 1);
+ if (IS_ERR(handle)) {
+ retval = PTR_ERR(handle);
+ goto err_out;
+ }
+ tmp_inode = ext4_new_inode(handle,
+ inode->i_sb->s_root->d_inode,
+ S_IFREG);
+ if (IS_ERR(tmp_inode)) {
+ retval = -ENOMEM;
+ ext4_journal_stop(handle);
+ tmp_inode = NULL;
+ goto err_out;
+ }
+ i_size_write(tmp_inode, i_size_read(inode));
+ /*
+ * We don't want the inode to be reclaimed
+ * if we got interrupted in between. We have
+ * this tmp inode carrying reference to the
+ * data blocks of the original file. We set
+ * the i_nlink to zero at the last stage after
+ * switching the original file to extent format
+ */
+ tmp_inode->i_nlink = 1;
+
+ ext4_ext_tree_init(handle, tmp_inode);
+ ext4_orphan_add(handle, tmp_inode);
+ ext4_journal_stop(handle);
+
+ 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;
+
+ /*
+ * start with one credit accounted for
+ * superblock modification.
+ *
+ * For the tmp_inode we already have commited the
+ * trascation that created the inode. Later as and
+ * when we add extents we extent the journal
+ */
+ handle = ext4_journal_start(inode, 1);
+ 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:
+ /*
+ * We are either freeing extent information or indirect
+ * blocks. During this we touch superblock, group descriptor
+ * and block bitmap. Later we mark the tmp_inode dirty
+ * via ext4_ext_tree_init. So allocate a credit of 4
+ * We may update quota (user and group).
+ *
+ * FIXME!! we may be touching bitmaps in different block groups.
+ */
+ if (ext4_journal_extend(handle,
+ 4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)) != 0) {
+
+ ext4_journal_restart(handle,
+ 4 + 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
+ }
+ 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, retval);
+ }
+
+ /*
+ * 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);
+
+ /*
+ * Set the i_nlink to zero so that
+ * generic_drop_inode really deletes the
+ * inode
+ */
+ tmp_inode->i_nlink = 0;
+
+ ext4_journal_stop(handle);
+
+ up_write(&EXT4_I(inode)->i_data_sem);
+
+ if (tmp_inode)
+ iput(tmp_inode);
+
+ return retval;
+}
diff --git a/include/linux/ext4_fs.h b/include/linux/ext4_fs.h
index b609294..213974f 100644
--- a/include/linux/ext4_fs.h
+++ b/include/linux/ext4_fs.h
@@ -243,6 +243,7 @@ struct ext4_new_group_data {
#endif
#define EXT4_IOC_GETRSVSZ _IOR('f', 5, long)
#define EXT4_IOC_SETRSVSZ _IOW('f', 6, long)
+#define EXT4_IOC_MIGRATE _IO('f', 7)

/*
* ioctl commands in 32 bit emulation
@@ -983,6 +984,9 @@ extern int ext4_ioctl (struct inode *, struct file *, unsigned int,
unsigned long);
extern long ext4_compat_ioctl (struct file *, unsigned int, unsigned long);

+/* migrate.c */
+extern int ext4_ext_migrate(struct inode *, struct file *, unsigned int,
+ unsigned long);
/* namei.c */
extern int ext4_orphan_add(handle_t *, struct inode *);
extern int ext4_orphan_del(handle_t *, struct inode *);
diff --git a/include/linux/ext4_fs_extents.h b/include/linux/ext4_fs_extents.h
index 023683b..db64509 100644
--- a/include/linux/ext4_fs_extents.h
+++ b/include/linux/ext4_fs_extents.h
@@ -212,6 +212,7 @@ static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
}

+extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
extern int ext4_extent_tree_init(handle_t *, struct inode *);
extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
extern int ext4_ext_try_to_merge(struct inode *inode,