ext4: online defrag -- Add EXT4_IOC_MOVE_EXT ioctl and related functions.
From: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
The EXT4_IOC_MOVE_EXT exchanges the blocks between orig_fd and donor_fd,
and then write the file data of orig_fd to donor_fd.
ext4_mext_move_extent() is the main fucntion of ext4 online defrag,
and this patch includes all functions related to ext4 online defrag.
Signed-off-by: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
Signed-off-by: Takashi Sato <t-sato@xxxxxxxxxxxxx>
Signed-off-by: Kazuya Mio <k-mio@xxxxxxxxxxxxx>
---
Makefile | 2
ext4.h | 15
ext4_extents.h | 4
extents.c | 4
ioctl.c | 36 +
move_extent.c | 1296 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 1354 insertions(+), 3 deletions(-)
diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
index 8a34710..8867b2a 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -6,7 +6,7 @@ obj-$(CONFIG_EXT4_FS) += ext4.o
ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
- ext4_jbd2.o migrate.o mballoc.o block_validity.o
+ ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o
ext4-$(CONFIG_EXT4_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9f0e482..ff55657 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -354,6 +354,7 @@ struct ext4_new_group_data {
/* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
/* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
#define EXT4_IOC_ALLOC_DA_BLKS _IO('f', 12)
+#define EXT4_IOC_MOVE_EXT _IOWR('f', 15, struct move_extent)
/*
* ioctl commands in 32 bit emulation
@@ -451,6 +452,15 @@ struct ext4_inode {
__le32 i_version_hi; /* high 32 bits for 64-bit version */
};
+struct move_extent {
+ int orig_fd; /* original file descriptor */
+ int donor_fd; /* donor file descriptor */
+ __u64 orig_start; /* logical start offset in block for orig */
+ __u64 donor_start; /* logical start offset in block for donor */
+ __u64 len; /* block length to be moved */
+ __u64 moved_len; /* moved block length */
+};
+#define MAX_DEFRAG_SIZE ((1UL<<31) - 1)
#define EXT4_EPOCH_BITS 2
#define EXT4_EPOCH_MASK ((1 << EXT4_EPOCH_BITS) - 1)
@@ -1652,6 +1662,11 @@ extern int ext4_get_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, int flags);
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len);
+/* defrag.c */
+extern int ext4_mext_move_extent(struct file *o_filp, struct file *d_filp,
+ __u64 start_orig, __u64 start_donor,
+ __u64 len, __u64 *moved_len);
+
/*
* Add new method to test wether block and inode bitmaps are properly
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index f0c3ec8..20a8410 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -221,12 +221,16 @@ static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
}
extern int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks);
+extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex);
extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
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_single_extent(struct inode *inode,
int num,
struct ext4_ext_path *path);
+extern int ext4_can_extents_be_merged(struct inode *inode,
+ struct ext4_extent *ex1,
+ struct ext4_extent *ex2);
extern int ext4_ext_try_to_merge(struct inode *inode,
struct ext4_ext_path *path,
struct ext4_extent *);
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index d4e99e9..1903d9b 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -49,7 +49,7 @@
* ext_pblock:
* combine low and high parts of physical block number into ext4_fsblk_t
*/
-static ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
+ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
{
ext4_fsblk_t block;
@@ -1417,7 +1417,7 @@ static int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
return err;
}
-static int
+int
ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
struct ext4_extent *ex2)
{
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 3b7faeb..68a7ddf 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -14,6 +14,7 @@
#include <linux/compat.h>
#include <linux/smp_lock.h>
#include <linux/mount.h>
+#include <linux/file.h>
#include <asm/uaccess.h>
#include "ext4_jbd2.h"
#include "ext4.h"
@@ -224,6 +225,41 @@ setversion_out:
return err;
}
+
+ case EXT4_IOC_MOVE_EXT: {
+ struct move_extent me;
+ struct file *donor_filp;
+ int err;
+
+ if (copy_from_user(&me,
+ (struct move_extent __user *)arg, sizeof(me)))
+ return -EFAULT;
+
+ donor_filp = fget(me.donor_fd);
+ if (!donor_filp)
+ return -EBADF;
+
+ if (!capable(CAP_DAC_OVERRIDE)) {
+ if ((current->real_cred->fsuid != inode->i_uid) ||
+ !(inode->i_mode & S_IRUSR) ||
+ !(donor_filp->f_dentry->d_inode->i_mode &
+ S_IRUSR)) {
+ fput(donor_filp);
+ return -EACCES;
+ }
+ }
+
+ err = ext4_mext_move_extent(filp, donor_filp, me.orig_start,
+ me.donor_start, me.len, &me.moved_len);
+ fput(donor_filp);
+
+ if (!err)
+ if (copy_to_user((struct move_extent *)arg,
+ &me, sizeof(me)))
+ return -EFAULT;
+ return err;
+ }
+
case EXT4_IOC_GROUP_ADD: {
struct ext4_new_group_data input;
struct super_block *sb = inode->i_sb;
diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
index e69de29..5b563f2 100644
--- a/fs/ext4/move_extent.c
+++ b/fs/ext4/move_extent.c
@@ -0,0 +1,1296 @@
+/*
+ * Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
+ * Written by Takashi Sato <t-sato@xxxxxxxxxxxxx>
+ * Akira Fujita <a-fujita@xxxxxxxxxxxxx>
+ *
+ * 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 will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/quotaops.h>
+#include "ext4_jbd2.h"
+#include "ext4_extents.h"
+#include "ext4.h"
+
+#define ext4_mext_get_extpath(path, inode, block, ret) \
+ do { \
+ path = ext4_ext_find_extent(inode, block, path); \
+ if (IS_ERR(path)) { \
+ ret = PTR_ERR(path); \
+ path = NULL; \
+ } \
+ } while (0)
+
+/**
+ * ext4_mext_copy_extent_status - Copy the extent's initialization status
+ *
+ * @src: an extent for getting initialize status
+ * @dest: an extent to be set the status
+ */
+static void
+ext4_mext_copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest)
+{
+ if (ext4_ext_is_uninitialized(src))
+ ext4_ext_mark_uninitialized(dest);
+ else
+ dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest));
+}
+
+/**
+ * ext4_mext_next_extent - Search for the next extent and set it to "extent"
+ *
+ * @inode: inode which is searched
+ * @path: this will obtain data for the next extent
+ * @extent: pointer to the next extent we have just gotten
+ *
+ * Search the next extent in the array of ext4_ext_path structure (@path)
+ * and set it to ext4_extent structure (@extent). In addition, the member of
+ * @path (->p_ext) also points the next extent. Return 0 on success, 1 if
+ * ext4_ext_path structure refers to the last extent, or a negative error
+ * value on failure.
+ */
+static int
+ext4_mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
+ struct ext4_extent **extent)
+{
+ int ppos, leaf_ppos = path->p_depth;
+
+ ppos = leaf_ppos;
+ if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) {
+ /* leaf block */
+ *extent = ++path[ppos].p_ext;
+ return 0;
+ }
+
+ while (--ppos >= 0) {
+ if (EXT_LAST_INDEX(path[ppos].p_hdr) >
+ path[ppos].p_idx) {
+ int cur_ppos = ppos;
+
+ /* index block */
+ path[ppos].p_idx++;
+ path[ppos].p_block = idx_pblock(path[ppos].p_idx);
+ if (path[ppos+1].p_bh)
+ brelse(path[ppos+1].p_bh);
+ path[ppos+1].p_bh =
+ sb_bread(inode->i_sb, path[ppos].p_block);
+ if (!path[ppos+1].p_bh)
+ return -EIO;
+ path[ppos+1].p_hdr =
+ ext_block_hdr(path[ppos+1].p_bh);
+
+ /* Halfway index block */
+ while (++cur_ppos < leaf_ppos) {
+ path[cur_ppos].p_idx =
+ EXT_FIRST_INDEX(path[cur_ppos].p_hdr);
+ path[cur_ppos].p_block =
+ idx_pblock(path[cur_ppos].p_idx);
+ if (path[cur_ppos+1].p_bh)
+ brelse(path[cur_ppos+1].p_bh);
+ path[cur_ppos+1].p_bh = sb_bread(inode->i_sb,
+ path[cur_ppos].p_block);
+ if (!path[cur_ppos+1].p_bh)
+ return -EIO;
+ path[cur_ppos+1].p_hdr =
+ ext_block_hdr(path[cur_ppos+1].p_bh);
+ }
+
+ /* leaf block */
+ path[leaf_ppos].p_ext = *extent =
+ EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr);
+ return 0;
+ }
+ }
+ /* We found the last extent */
+ return 1;
+}
+
+/**
+ * ext4_mext_double_down_read - Acquire two inodes' read semaphore
+ *
+ * @orig_inode: original inode structure
+ * @donor_inode: donor inode structure
+ * Acquire read semaphore of the two inodes (orig and donor) by i_ino order.
+ */
+static void
+ext4_mext_double_down_read(struct inode *orig_inode,
+ struct inode *donor_inode)
+{
+ struct inode *first = orig_inode, *second = donor_inode;
+
+ BUG_ON(orig_inode == NULL || donor_inode == NULL);
+
+ /*
+ * Use the inode number to provide the stable locking order instead
+ * of its address, because the C language doesn't guarantee you can
+ * compare pointers that don't come from the same array.
+ */
+ if (donor_inode->i_ino < orig_inode->i_ino) {
+ first = donor_inode;
+ second = orig_inode;
+ }
+
+ down_read(&EXT4_I(first)->i_data_sem);
+ down_read(&EXT4_I(second)->i_data_sem);
+}
+
+/**
+ * ext4_mext_double_down_write - Acquire two inodes' write semaphore
+ *
+ * @orig_inode: original inode structure
+ * @donor_inode: donor inode structure
+ * Acquire write semaphore of the two inodes (orig and donor) by i_ino order.
+ */
+static void
+ext4_mext_double_down_write(struct inode *orig_inode,
+ struct inode *donor_inode)
+{
+ struct inode *first = orig_inode, *second = donor_inode;
+
+ BUG_ON(orig_inode == NULL || donor_inode == NULL);
+
+ /*
+ * Use the inode number to provide the stable locking order instead
+ * of its address, because the C language doesn't guarantee you can
+ * compare pointers that don't come from the same array.
+ */
+ if (donor_inode->i_ino < orig_inode->i_ino) {
+ first = donor_inode;
+ second = orig_inode;
+ }
+
+ down_write(&EXT4_I(first)->i_data_sem);
+ down_write(&EXT4_I(second)->i_data_sem);
+}
+
+/**
+ * ext4_mext_double_up_read - Release two inodes' read semaphore
+ *
+ * @orig_inode: original inode structure to be released its lock first
+ * @donor_inode: donor inode structure to be released its lock second
+ * Release read semaphore of two inodes (orig and donor).
+ */
+static void
+ext4_mext_double_up_read(struct inode *orig_inode, struct inode *donor_inode)
+{
+ BUG_ON(orig_inode == NULL || donor_inode == NULL);
+
+ up_read(&EXT4_I(orig_inode)->i_data_sem);
+ up_read(&EXT4_I(donor_inode)->i_data_sem);
+}
+
+/**
+ * ext4_mext_double_up_write - Release two inodes' write semaphore
+ *
+ * @orig_inode: original inode structure to be released its lock first
+ * @donor_inode: donor inode structure to be released its lock second
+ * Release write semaphore of two inodes (orig and donor).
+ */
+static void
+ext4_mext_double_up_write(struct inode *orig_inode, struct inode *donor_inode)
+{
+ BUG_ON(orig_inode == NULL || donor_inode == NULL);
+
+ up_write(&EXT4_I(orig_inode)->i_data_sem);
+ up_write(&EXT4_I(donor_inode)->i_data_sem);
+}
+
+/**
+ * ext4_mext_insert_across_blocks - Insert extents across leaf block
+ *
+ * @handle: journal handle
+ * @orig_inode: original inode
+ * @o_start: first original extent to be changed
+ * @o_end: last original extent to be changed
+ * @start_ext: first new extent to be inserted
+ * @new_ext: middle of new extent to be inserted
+ * @end_ext: last new extent to be inserted
+ *
+ * Allocate a new leaf block and insert extents into it. Return 0 on success,
+ * or a negative error value on failure.
+ */
+static int
+ext4_mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
+ struct ext4_extent *o_start, struct ext4_extent *o_end,
+ struct ext4_extent *start_ext, struct ext4_extent *new_ext,
+ struct ext4_extent *end_ext)
+{
+ struct ext4_ext_path *orig_path = NULL;
+ ext4_lblk_t eblock = 0;
+ int new_flag = 0;
+ int end_flag = 0;
+ int err = 0;
+
+ if (start_ext->ee_len && new_ext->ee_len && end_ext->ee_len) {
+ if (o_start == o_end) {
+
+ /* start_ext new_ext end_ext
+ * donor |---------|-----------|--------|
+ * orig |------------------------------|
+ */
+ end_flag = 1;
+ } else {
+
+ /* start_ext new_ext end_ext
+ * donor |---------|----------|---------|
+ * orig |---------------|--------------|
+ */
+ o_end->ee_block = end_ext->ee_block;
+ o_end->ee_len = end_ext->ee_len;
+ ext4_ext_store_pblock(o_end, ext_pblock(end_ext));
+ }
+
+ o_start->ee_len = start_ext->ee_len;
+ new_flag = 1;
+
+ } else if (start_ext->ee_len && new_ext->ee_len &&
+ !end_ext->ee_len && o_start == o_end) {
+
+ /* start_ext new_ext
+ * donor |--------------|---------------|
+ * orig |------------------------------|
+ */
+ o_start->ee_len = start_ext->ee_len;
+ new_flag = 1;
+
+ } else if (!start_ext->ee_len && new_ext->ee_len &&
+ end_ext->ee_len && o_start == o_end) {
+
+ /* new_ext end_ext
+ * donor |--------------|---------------|
+ * orig |------------------------------|
+ */
+ o_end->ee_block = end_ext->ee_block;
+ o_end->ee_len = end_ext->ee_len;
+ ext4_ext_store_pblock(o_end, ext_pblock(end_ext));
+
+ /*
+ * Set 0 to the extent block if new_ext was
+ * the first block.
+ */
+ if (new_ext->ee_block)
+ eblock = le32_to_cpu(new_ext->ee_block);
+
+ new_flag = 1;
+ } else {
+ ext4_debug("ext4 move extent: Unexpected insert case\n");
+ return -EIO;
+ }
+
+ if (new_flag) {
+ ext4_mext_get_extpath(orig_path, orig_inode, eblock, err);
+ if (orig_path == NULL)
+ goto out;
+
+ if (ext4_ext_insert_extent(handle, orig_inode,
+ orig_path, new_ext))
+ goto out;
+ }
+
+ if (end_flag) {
+ ext4_mext_get_extpath(orig_path, orig_inode,
+ le32_to_cpu(end_ext->ee_block) - 1, err);
+ if (orig_path == NULL)
+ goto out;
+
+ if (ext4_ext_insert_extent(handle, orig_inode,
+ orig_path, end_ext))
+ goto out;
+ }
+out:
+ if (orig_path) {
+ ext4_ext_drop_refs(orig_path);
+ kfree(orig_path);
+ }
+
+ return err;
+
+}
+
+/**
+ * ext4_mext_insert_inside_block - Insert new extent to the extent block
+ *
+ * @o_start: first original extent to be moved
+ * @o_end: last original extent to be moved
+ * @start_ext: first new extent to be inserted
+ * @new_ext: middle of new extent to be inserted
+ * @end_ext: last new extent to be inserted
+ * @eh: extent header of target leaf block
+ * @range_to_move: used to decide how to insert extent
+ *
+ * Insert extents into the leaf block. The extent (@o_start) is overwritten
+ * by inserted extents.
+ */
+static void
+ext4_mext_insert_inside_block(struct ext4_extent *o_start,
+ struct ext4_extent *o_end, struct ext4_extent *start_ext,
+ struct ext4_extent *new_ext, struct ext4_extent *end_ext,
+ struct ext4_extent_header *eh, int range_to_move)
+{
+ int i = 0;
+ unsigned long len;
+
+ /* Move the existing extents */
+ if (range_to_move && o_end < EXT_LAST_EXTENT(eh)) {
+ len = (unsigned long)(EXT_LAST_EXTENT(eh) + 1) -
+ (unsigned long)(o_end + 1);
+ memmove(o_end + 1 + range_to_move, o_end + 1, len);
+ }
+
+ /* Insert start entry */
+ if (start_ext->ee_len)
+ o_start[i++].ee_len = start_ext->ee_len;
+
+ /* Insert new entry */
+ if (new_ext->ee_len) {
+ o_start[i] = *new_ext;
+ ext4_ext_store_pblock(&o_start[i++], ext_pblock(new_ext));
+ }
+
+ /* Insert end entry */
+ if (end_ext->ee_len)
+ o_start[i] = *end_ext;
+
+ /* Increment the total entries counter on the extent block */
+ le16_add_cpu(&eh->eh_entries, range_to_move);
+}
+
+/**
+ * ext4_mext_insert_extents - Insert new extent
+ *
+ * @handle: journal handle
+ * @orig_inode: original inode
+ * @orig_path: path indicates first extent to be changed
+ * @o_start: first original extent to be changed
+ * @o_end: last original extent to be changed
+ * @start_ext: first new extent to be inserted
+ * @new_ext: middle of new extent to be inserted
+ * @end_ext: last new extent to be inserted
+ *
+ * Call the function to insert extents. If we cannot add more extents into
+ * the leaf block, we call ext4_mext_insert_across_blocks() to create a
+ * new leaf block. Otherwise call ext4_mext_insert_inside_block(). Return 0
+ * on success, or a negative error value on failure.
+ */
+static int
+ext4_mext_insert_extents(handle_t *handle, struct inode *orig_inode,
+ struct ext4_ext_path *orig_path, struct ext4_extent *o_start,
+ struct ext4_extent *o_end, struct ext4_extent *start_ext,
+ struct ext4_extent *new_ext, struct ext4_extent *end_ext)
+{
+ struct ext4_extent_header *eh;
+ unsigned long need_slots, slots_range;
+ int range_to_move, depth, ret;
+
+ /*
+ * The extents need to be inserted
+ * start_extent + new_extent + end_extent.
+ */
+ need_slots = (start_ext->ee_len ? 1 : 0) + (end_ext->ee_len ? 1 : 0) +
+ (new_ext->ee_len ? 1 : 0);
+
+ /* The number of slots between start and end */
+ slots_range = ((unsigned long)(o_end + 1) - (unsigned long)o_start + 1)
+ / sizeof(struct ext4_extent);
+
+ /* Range to move the end of extent */
+ range_to_move = need_slots - slots_range;
+ depth = orig_path->p_depth;
+ orig_path += depth;
+ eh = orig_path->p_hdr;
+
+ if (depth) {
+ /* Register to journal */
+ ret = ext4_journal_get_write_access(handle, orig_path->p_bh);
+ if (ret)
+ return ret;
+ }
+
+ /* Expansion */
+ if (range_to_move > 0 &&
+ (range_to_move > le16_to_cpu(eh->eh_max)
+ - le16_to_cpu(eh->eh_entries))) {
+
+ ret = ext4_mext_insert_across_blocks(handle, orig_inode,
+ o_start, o_end, start_ext, new_ext, end_ext);
+ if (ret < 0)
+ return ret;
+ } else
+ ext4_mext_insert_inside_block(o_start, o_end, start_ext,
+ new_ext, end_ext, eh, range_to_move);
+
+ if (depth) {
+ ret = ext4_handle_dirty_metadata(handle, orig_inode,
+ orig_path->p_bh);
+ if (ret)
+ return ret;
+ } else {
+ ret = ext4_mark_inode_dirty(handle, orig_inode);
+ if (ret < 0)
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * ext4_mext_leaf_block - Move one leaf extent block into the inode.
+ *
+ * @handle: journal handle
+ * @orig_inode: original inode
+ * @orig_path: path indicates first extent to be changed
+ * @dext: donor extent
+ * @from: start offset on the target file
+ *
+ * In order to insert extents into the leaf block, we must divide the extent
+ * in the leaf block into three extents. The one is located to be inserted
+ * extents, and the others are located around it.
+ *
+ * Therefore, this function creates structures to save extents of the leaf
+ * block, and inserts extents by calling ext4_mext_insert_extents() with
+ * created extents. Return 0 on success, or a negative error value on failure.
+ */
+static int
+ext4_mext_leaf_block(handle_t *handle, struct inode *orig_inode,
+ struct ext4_ext_path *orig_path, struct ext4_extent *dext,
+ ext4_lblk_t *from)
+{
+ struct ext4_extent *oext, *o_start, *o_end, *prev_ext;
+ struct ext4_extent new_ext, start_ext, end_ext;
+ ext4_lblk_t new_ext_end;
+ ext4_fsblk_t new_phys_end;
+ int oext_alen, new_ext_alen, end_ext_alen;
+ int depth = ext_depth(orig_inode);
+ int ret;
+
+ o_start = o_end = oext = orig_path[depth].p_ext;
+ oext_alen = ext4_ext_get_actual_len(oext);
+ start_ext.ee_len = end_ext.ee_len = 0;
+
+ new_ext.ee_block = cpu_to_le32(*from);
+ ext4_ext_store_pblock(&new_ext, ext_pblock(dext));
+ new_ext.ee_len = dext->ee_len;
+ new_ext_alen = ext4_ext_get_actual_len(&new_ext);
+ new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
+ new_phys_end = ext_pblock(&new_ext) + new_ext_alen - 1;
+
+ /*
+ * Case: original extent is first
+ * oext |--------|
+ * new_ext |--|
+ * start_ext |--|
+ */
+ if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) &&
+ le32_to_cpu(new_ext.ee_block) <
+ le32_to_cpu(oext->ee_block) + oext_alen) {
+ start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
+ le32_to_cpu(oext->ee_block));
+ ext4_mext_copy_extent_status(oext, &start_ext);
+ } else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
+ prev_ext = oext - 1;
+ /*
+ * We can merge new_ext into previous extent,
+ * if these are contiguous and same extent type.
+ */
+ if (ext4_can_extents_be_merged(orig_inode, prev_ext,
+ &new_ext)) {
+ o_start = prev_ext;
+ start_ext.ee_len = cpu_to_le16(
+ ext4_ext_get_actual_len(prev_ext) +
+ new_ext_alen);
+ ext4_mext_copy_extent_status(prev_ext, &start_ext);
+ new_ext.ee_len = 0;
+ }
+ }
+
+ /*
+ * Case: new_ext_end must be less than oext
+ * oext |-----------|
+ * new_ext |-------|
+ */
+ BUG_ON(le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end);
+
+ /*
+ * Case: new_ext is smaller than original extent
+ * oext |---------------|
+ * new_ext |-----------|
+ * end_ext |---|
+ */
+ if (le32_to_cpu(oext->ee_block) <= new_ext_end &&
+ new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) {
+ end_ext.ee_len =
+ cpu_to_le16(le32_to_cpu(oext->ee_block) +
+ oext_alen - 1 - new_ext_end);
+ ext4_mext_copy_extent_status(oext, &end_ext);
+ end_ext_alen = ext4_ext_get_actual_len(&end_ext);
+ ext4_ext_store_pblock(&end_ext,
+ (ext_pblock(o_end) + oext_alen - end_ext_alen));
+ end_ext.ee_block =
+ cpu_to_le32(le32_to_cpu(o_end->ee_block) +
+ oext_alen - end_ext_alen);
+ }
+
+ ret = ext4_mext_insert_extents(handle, orig_inode,
+ orig_path, o_start, o_end, &start_ext,
+ &new_ext, &end_ext);
+ return ret;
+}
+
+/**
+ * ext4_mext_get_replaced_extent - Compute extents for extent swapping.
+ *
+ * @tmp_dext: the extent that will belong to the original inode
+ * @tmp_oext: the extent that will belong to the donor inode
+ * @orig_off: block offset of original inode
+ * @donor_off: block offset of donor inode
+ * @max_count: the maximun length of extents
+ */
+static void
+ext4_mext_get_replaced_extent(struct ext4_extent *tmp_dext,
+ struct ext4_extent *tmp_oext,
+ ext4_lblk_t orig_off, ext4_lblk_t donor_off,
+ ext4_lblk_t max_count)
+{
+ ext4_lblk_t diff, orig_diff;
+ struct ext4_extent dext_old, oext_old;
+
+ dext_old = *tmp_dext;
+ oext_old = *tmp_oext;
+
+ /* When tmp_dext is too large, pick up the target range. */
+ diff = donor_off - le32_to_cpu(tmp_dext->ee_block);
+
+ ext4_ext_store_pblock(tmp_dext, ext_pblock(tmp_dext) + diff);
+ tmp_dext->ee_block =
+ cpu_to_le32(le32_to_cpu(tmp_dext->ee_block) + diff);
+ tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_dext->ee_len) - diff);
+
+ if (max_count < ext4_ext_get_actual_len(tmp_dext))
+ tmp_dext->ee_len = cpu_to_le16(max_count);
+
+ orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block);
+ ext4_ext_store_pblock(tmp_oext, ext_pblock(tmp_oext) + orig_diff);
+
+ /* Adjust extent length if donor extent is larger than orig */
+ if (ext4_ext_get_actual_len(tmp_dext) >
+ ext4_ext_get_actual_len(tmp_oext) - orig_diff)
+ tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) -
+ orig_diff);
+
+ tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext));
+
+ ext4_mext_copy_extent_status(&oext_old, tmp_dext);
+ ext4_mext_copy_extent_status(&dext_old, tmp_oext);
+}
+
+/**
+ * ext4_mext_replace_branches - Replace original extents with new extents
+ *
+ * @handle: journal handle
+ * @orig_inode: original inode
+ * @donor_inode: donor inode
+ * @from: block offset of orig_inode
+ * @count: block count to be replaced
+ *
+ * Replace original inode extents and donor inode extents page by page.
+ * We implement this replacement in the following three steps:
+ * 1. Save the block information of original and donor inodes into
+ * dummy extents.
+ * 2. Change the block information of original inode to point at the
+ * donor inode blocks.
+ * 3. Change the block information of donor inode to point at the saved
+ * original inode blocks in the dummy extents.
+ *
+ * Return 0 on success, or a negative error value on failure.
+ */
+static int
+ext4_mext_replace_branches(handle_t *handle, struct inode *orig_inode,
+ struct inode *donor_inode, ext4_lblk_t from,
+ ext4_lblk_t count)
+{
+ struct ext4_ext_path *orig_path = NULL;
+ struct ext4_ext_path *donor_path = NULL;
+ struct ext4_extent *oext, *dext;
+ struct ext4_extent tmp_dext, tmp_oext;
+ ext4_lblk_t orig_off = from, donor_off = from;
+ int err = 0;
+ int depth;
+ int replaced_count = 0;
+ int dext_alen;
+
+ ext4_mext_double_down_write(orig_inode, donor_inode);
+
+ /* Get the original extent for the block "orig_off" */
+ ext4_mext_get_extpath(orig_path, orig_inode, orig_off, err);
+ if (orig_path == NULL)
+ goto out;
+
+ /* Get the donor extent for the head */
+ ext4_mext_get_extpath(donor_path, donor_inode, donor_off, err);
+ if (donor_path == NULL)
+ goto out;
+ depth = ext_depth(orig_inode);
+ oext = orig_path[depth].p_ext;
+ tmp_oext = *oext;
+
+ depth = ext_depth(donor_inode);
+ dext = donor_path[depth].p_ext;
+ tmp_dext = *dext;
+
+ ext4_mext_get_replaced_extent(&tmp_dext, &tmp_oext, orig_off,
+ donor_off, count);
+
+ /* Loop for the donor extents */
+ while (1) {
+ /* The extent for donor must be found. */
+ BUG_ON(!dext || donor_off != le32_to_cpu(dext->ee_block));
+
+ /* Set donor extent to orig extent */
+ err = ext4_mext_leaf_block(handle, orig_inode,
+ orig_path, &tmp_dext, &orig_off);
+ if (err < 0)
+ goto out;
+
+ /* Set orig extent to donor extent */
+ err = ext4_mext_leaf_block(handle, donor_inode,
+ donor_path, &tmp_oext, &donor_off);
+ if (err < 0)
+ goto out;
+
+ dext_alen = ext4_ext_get_actual_len(&tmp_dext);
+ replaced_count += dext_alen;
+ donor_off += dext_alen;
+ orig_off += dext_alen;
+
+ /* Already moved the expected blocks */
+ if (replaced_count >= count)
+ break;
+
+ if (orig_path)
+ ext4_ext_drop_refs(orig_path);
+ ext4_mext_get_extpath(orig_path, orig_inode, orig_off, err);
+ if (orig_path == NULL)
+ goto out;
+ depth = ext_depth(orig_inode);
+ oext = orig_path[depth].p_ext;
+ if (le32_to_cpu(oext->ee_block) +
+ ext4_ext_get_actual_len(oext) <= orig_off) {
+ err = 0;
+ goto out;
+ }
+ tmp_oext = *oext;
+
+ if (donor_path)
+ ext4_ext_drop_refs(donor_path);
+ ext4_mext_get_extpath(donor_path, donor_inode,
+ donor_off, err);
+ if (donor_path == NULL)
+ goto out;
+ depth = ext_depth(donor_inode);
+ dext = donor_path[depth].p_ext;
+ if (le32_to_cpu(dext->ee_block) +
+ ext4_ext_get_actual_len(dext) <= donor_off) {
+ err = 0;
+ goto out;
+ }
+ tmp_dext = *dext;
+
+ ext4_mext_get_replaced_extent(&tmp_dext, &tmp_oext, orig_off,
+ donor_off, count - replaced_count);
+ }
+
+out:
+ if (orig_path) {
+ ext4_ext_drop_refs(orig_path);
+ kfree(orig_path);
+ }
+ if (donor_path) {
+ ext4_ext_drop_refs(donor_path);
+ kfree(donor_path);
+ }
+
+ ext4_mext_double_up_write(orig_inode, donor_inode);
+ return err;
+}
+
+/**
+ * ext4_mext_partial - Move extent data per page
+ *
+ * @o_filp: file structure of original file
+ * @donor_inode: donor inode
+ * @orig_page_offset: page index on original file
+ * @data_offset_in_page: block index where data swapping starts
+ * @block_len_in_page: the number of blocks to be swapped
+ * @uninit: orig extent is uninitialized or not
+ *
+ * Save the data in original inode blocks and replace original inode extents
+ * with donor inode extents by calling ext4_mext_replace_branches().
+ * Finally, write out the saved data in new original inode blocks. Return 0
+ * on success, or a negative error value on failure.
+ */
+static int
+ext4_mext_partial(struct file *o_filp, struct inode *donor_inode,
+ pgoff_t orig_page_offset, int data_offset_in_page,
+ int block_len_in_page, int uninit)
+{
+ struct inode *orig_inode = o_filp->f_dentry->d_inode;
+ struct address_space *mapping = orig_inode->i_mapping;
+ struct buffer_head *bh;
+ struct page *page = NULL;
+ const struct address_space_operations *a_ops = mapping->a_ops;
+ handle_t *handle;
+ ext4_lblk_t orig_blk_offset;
+ long long offs = orig_page_offset << PAGE_CACHE_SHIFT;
+ unsigned long blocksize = orig_inode->i_sb->s_blocksize;
+ unsigned int w_flags = 0;
+ unsigned int tmp_data_len, data_len;
+ void *fsdata;
+ int ret, i, jblocks;
+ int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
+
+ /*
+ * It needs twice the amount of ordinary journal buffers because
+ * inode and donor_inode may change each different metadata blocks.
+ */
+ jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
+ handle = ext4_journal_start(orig_inode, jblocks);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ return ret;
+ }
+
+ if (segment_eq(get_fs(), KERNEL_DS))
+ w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
+
+ orig_blk_offset = orig_page_offset * blocks_per_page +
+ data_offset_in_page;
+
+ /*
+ * If orig extent is uninitialized one,
+ * it's not necessary force the page into memory
+ * and then force it to be written out again.
+ * Just swap data blocks between orig and donor.
+ */
+ if (uninit) {
+ ret = ext4_mext_replace_branches(handle, orig_inode,
+ donor_inode, orig_blk_offset,
+ block_len_in_page);
+
+ /* Clear the inode cache not to refer to the old data */
+ ext4_ext_invalidate_cache(orig_inode);
+ ext4_ext_invalidate_cache(donor_inode);
+ goto out2;
+ }
+
+ offs = (long long)orig_blk_offset << orig_inode->i_blkbits;
+
+ /* Calculate data_len */
+ if ((orig_blk_offset + block_len_in_page - 1) ==
+ ((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
+ /* Replace the last block */
+ tmp_data_len = orig_inode->i_size & (blocksize - 1);
+ /*
+ * If data_len equal zero, it shows data_len is multiples of
+ * blocksize. So we set appropriate value.
+ */
+ if (tmp_data_len == 0)
+ tmp_data_len = blocksize;
+
+ data_len = tmp_data_len +
+ ((block_len_in_page - 1) << orig_inode->i_blkbits);
+ } else {
+ data_len = block_len_in_page << orig_inode->i_blkbits;
+ }
+
+ ret = a_ops->write_begin(o_filp, mapping, offs, data_len, w_flags,
+ &page, &fsdata);
+ if (unlikely(ret < 0))
+ goto out;
+
+ if (!PageUptodate(page)) {
+ mapping->a_ops->readpage(o_filp, page);
+ lock_page(page);
+ }
+
+ /*
+ * try_to_release_page() doesn't call releasepage in writeback mode.
+ * We should care about the order of writing to the same file
+ * by multiple move extent processes.
+ * It needs to call wait_on_page_writeback() to wait for the
+ * writeback of the page.
+ */
+ if (PageWriteback(page))
+ wait_on_page_writeback(page);
+
+ /* Release old bh and drop refs */
+ try_to_release_page(page, 0);
+
+ ret = ext4_mext_replace_branches(handle, orig_inode, donor_inode,
+ orig_blk_offset, block_len_in_page);
+ if (ret < 0)
+ goto out;
+
+ /* Clear the inode cache not to refer to the old data */
+ ext4_ext_invalidate_cache(orig_inode);
+ ext4_ext_invalidate_cache(donor_inode);
+
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, 1 << orig_inode->i_blkbits, 0);
+
+ bh = page_buffers(page);
+ for (i = 0; i < data_offset_in_page; i++)
+ bh = bh->b_this_page;
+
+ for (i = 0; i < block_len_in_page; i++) {
+ ret = ext4_get_block(orig_inode,
+ (sector_t)(orig_blk_offset + i), bh, 0);
+ if (ret < 0)
+ goto out;
+
+ if (bh->b_this_page != NULL)
+ bh = bh->b_this_page;
+ }
+
+ ret = a_ops->write_end(o_filp, mapping, offs, data_len, data_len, page,
+ fsdata);
+ page = NULL;
+
+out:
+ if (unlikely(page)) {
+ if (PageLocked(page))
+ unlock_page(page);
+ page_cache_release(page);
+ }
+out2:
+ ext4_journal_stop(handle);
+
+ return ret < 0 ? ret : 0;
+}
+
+/**
+ * ext4_mext_check_argumants - Check whether move extent can be done
+ *
+ * @orig_inode: original inode
+ * @donor_inode: donor inode
+ * @orig_start: logical start offset in block for orig
+ * @donor_start: logical start offset in block for donor
+ * @len: the number of blocks to be moved
+ * @moved_len: moved block length
+ *
+ * Check the arguments of ext4_mext_move_extent() whether the files can be
+ * exchanged each other.
+ * Return 0 on success, or a negative error value on failure.
+ */
+static int
+ext4_mext_check_arguments(struct inode *orig_inode,
+ struct inode *donor_inode, __u64 orig_start,
+ __u64 donor_start, __u64 len, __u64 moved_len)
+{
+ /* Regular file check */
+ if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
+ ext4_debug("ext4 move extent: The argument files should be "
+ "regular file [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ /* Ext4 move extent does not support swapfile */
+ if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
+ ext4_debug("ext4 move extent: The argument files should "
+ "not be swapfile [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ /* Files should be in the same ext4 FS */
+ if (orig_inode->i_sb != donor_inode->i_sb) {
+ ext4_debug("ext4 move extent: The argument files "
+ "should be in same FS [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ /* orig and donor should be different file */
+ if (orig_inode->i_ino == donor_inode->i_ino) {
+ ext4_debug("ext4 move extent: The argument files should not "
+ "be same file [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ /* Ext4 move extent supports only extent based file */
+ if (!(EXT4_I(orig_inode)->i_flags & EXT4_EXTENTS_FL)) {
+ ext4_debug("ext4 move extent: orig file is not extents "
+ "based file [ino:orig %lu]\n", orig_inode->i_ino);
+ return -EOPNOTSUPP;
+ } else if (!(EXT4_I(donor_inode)->i_flags & EXT4_EXTENTS_FL)) {
+ ext4_debug("ext4 move extent: donor file is not extents "
+ "based file [ino:donor %lu]\n", donor_inode->i_ino);
+ return -EOPNOTSUPP;
+ }
+
+ /* Start offset should be same */
+ if (orig_start != donor_start) {
+ ext4_debug("ext4 move extent: orig and donor's start "
+ "offset are not same [ino:orig %lu, donor %lu]\n",
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ if (moved_len) {
+ ext4_debug("ext4 move extent: moved_len should be 0 "
+ "[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
+ donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ if ((orig_start > MAX_DEFRAG_SIZE) ||
+ (donor_start > MAX_DEFRAG_SIZE) ||
+ (len > MAX_DEFRAG_SIZE) ||
+ (orig_start + len > MAX_DEFRAG_SIZE)) {
+ ext4_debug("ext4 move extent: Can't handle over [%lu] blocks "
+ "[ino:orig %lu, donor %lu]\n", MAX_DEFRAG_SIZE,
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ if (orig_inode->i_size > donor_inode->i_size) {
+ if (orig_start >= donor_inode->i_size) {
+ ext4_debug("ext4 move extent: orig start offset "
+ "[%llu] should be less than donor file size "
+ "[%lld] [ino:orig %lu, donor_inode %lu]\n",
+ orig_start, donor_inode->i_size,
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ if (orig_start + len > donor_inode->i_size) {
+ ext4_debug("ext4 move extent: End offset [%llu] should "
+ "be less than donor file size [%lld]."
+ "So adjust length from %llu to %lld "
+ "[ino:orig %lu, donor %lu]\n",
+ orig_start + len, donor_inode->i_size,
+ len, donor_inode->i_size - orig_start,
+ orig_inode->i_ino, donor_inode->i_ino);
+ len = donor_inode->i_size - orig_start;
+ }
+ } else {
+ if (orig_start >= orig_inode->i_size) {
+ ext4_debug("ext4 move extent: start offset [%llu] "
+ "should be less than original file size "
+ "[%lld] [inode:orig %lu, donor %lu]\n",
+ orig_start, orig_inode->i_size,
+ orig_inode->i_ino, donor_inode->i_ino);
+ return -EINVAL;
+ }
+
+ if (orig_start + len > orig_inode->i_size) {
+ ext4_debug("ext4 move extent: Adjust length "
+ "from %llu to %lld. Because it should be "
+ "less than original file size "
+ "[ino:orig %lu, donor %lu]\n",
+ len, orig_inode->i_size - orig_start,
+ orig_inode->i_ino, donor_inode->i_ino);
+ len = orig_inode->i_size - orig_start;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * ext4_mext_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
+ *
+ * @inode1: the inode structure
+ * @inode2: the inode structure
+ *
+ * Lock two inodes' i_mutex by i_ino order. This function is moved from
+ * fs/inode.c.
+ */
+void ext4_mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
+{
+ if (inode1 == NULL || inode2 == NULL || inode1 == inode2) {
+ if (inode1)
+ mutex_lock(&inode1->i_mutex);
+ else if (inode2)
+ mutex_lock(&inode2->i_mutex);
+ return;
+ }
+
+ if (inode1->i_ino < inode2->i_ino) {
+ mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
+ mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
+ } else {
+ mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
+ mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
+ }
+}
+
+/**
+ * ext4_mext_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
+ *
+ * @inode1: the inode that is released first
+ * @inode2: the inode that is released second
+ *
+ * This function is moved from fs/inode.c.
+ */
+
+void ext4_mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
+{
+ if (inode1)
+ mutex_unlock(&inode1->i_mutex);
+
+ if (inode2 && inode2 != inode1)
+ mutex_unlock(&inode2->i_mutex);
+}
+
+/**
+ * ext4_mext_move_extent - Exchange the specified range of a file
+ *
+ * @o_filp: file structure of the original file
+ * @d_filp: file structure of the donor file
+ * @orig_start: start offset in block for orig
+ * @donor_start: start offset in block for donor
+ * @len: the number of blocks to be moved
+ * @moved_len: moved block length
+ *
+ * This function returns 0 and moved block length is set in moved_len
+ * if succeed, otherwise returns error value.
+ *
+ * Note: ext4_mext_move_extent() proceeds the following order.
+ * 1:ext4_mext_move_extent() calculates the last block number of moving extent
+ * function by the start block number (orig_start) and the number of blocks
+ * to be moved (len) specified as arguments.
+ * If the {orig, donor}_start points a hole, the extent's start offset
+ * pointed by ext_cur (current extent), holecheck_path, orig_path are set
+ * after hole behind.
+ * 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
+ * or the ext_cur exceeds the block_end which is last logical block number.
+ * 3:To get the length of continues area, call ext4_mext_next_extent()
+ * specified with the ext_cur (initial value is holecheck_path) re-cursive,
+ * until find un-continuous extent, the start logical block number exceeds
+ * the block_end or the extent points to the last extent.
+ * 4:Exchange the original inode data with donor inode data
+ * from orig_page_offset to seq_end_page.
+ * The start indexes of data are specified as arguments.
+ * That of the original inode is orig_page_offset,
+ * and the donor inode is also orig_page_offset
+ * (To easily handle blocksize != pagesize case, the offset for the
+ * donor inode is block unit).
+ * 5:Update holecheck_path and orig_path to points a next proceeding extent,
+ * then returns to step 2.
+ * 6:Release holecheck_path, orig_path and set the len to moved_len
+ * which shows the number of moved blocks.
+ * The moved_len is useful for the command to calculate the file offset
+ * for starting next move extent ioctl.
+ * 7:Return 0 on success, or a negative error value on failure.
+ */
+int
+ext4_mext_move_extent(struct file *o_filp, struct file *d_filp,
+ __u64 orig_start, __u64 donor_start, __u64 len, __u64 *moved_len)
+{
+ struct inode *orig_inode = o_filp->f_dentry->d_inode;
+ struct inode *donor_inode = d_filp->f_dentry->d_inode;
+ struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL;
+ struct ext4_extent *ext_prev, *ext_cur, *ext_dummy;
+ ext4_lblk_t block_start = orig_start;
+ ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
+ ext4_lblk_t rest_blocks;
+ pgoff_t orig_page_offset = 0, seq_end_page;
+ int ret, depth, last_extent = 0;
+ int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
+ int data_offset_in_page;
+ int block_len_in_page;
+ int uninit;
+
+ /* protect orig and donor against a truncate */
+ ext4_mext_inode_double_lock(orig_inode, donor_inode);
+
+ ext4_mext_double_down_read(orig_inode, donor_inode);
+ /* Check the filesystem environment whether move_extent can be done */
+ ret = ext4_mext_check_arguments(orig_inode, donor_inode,
+ orig_start, donor_start, len, *moved_len);
+ ext4_mext_double_up_read(orig_inode, donor_inode);
+ if (ret)
+ goto out2;
+
+ file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
+ block_end = block_start + len - 1;
+ if (file_end < block_end)
+ len -= block_end - file_end;
+
+ ext4_mext_get_extpath(orig_path, orig_inode, block_start, ret);
+ if (orig_path == NULL)
+ goto out2;
+
+ /* Get path structure to check the hole */
+ ext4_mext_get_extpath(holecheck_path, orig_inode, block_start, ret);
+ if (holecheck_path == NULL)
+ goto out;
+
+ depth = ext_depth(orig_inode);
+ ext_cur = holecheck_path[depth].p_ext;
+ if (ext_cur == NULL)
+ goto out;
+
+ /*
+ * Get proper extent whose ee_block is beyond block_start
+ * if block_start was within the hole.
+ */
+ if (le32_to_cpu(ext_cur->ee_block) +
+ ext4_ext_get_actual_len(ext_cur) - 1 < block_start) {
+ last_extent = ext4_mext_next_extent(orig_inode,
+ holecheck_path, &ext_cur);
+ if (last_extent < 0) {
+ ret = last_extent;
+ goto out;
+ }
+ last_extent = ext4_mext_next_extent(orig_inode, orig_path,
+ &ext_dummy);
+ if (last_extent < 0) {
+ ret = last_extent;
+ goto out;
+ }
+ }
+ seq_start = block_start;
+
+ /* No blocks within the specified range. */
+ if (le32_to_cpu(ext_cur->ee_block) > block_end) {
+ ext4_debug("ext4 move extent: The specified range of file "
+ "may be the hole\n");
+ goto out;
+ }
+
+ /* Adjust start blocks */
+ add_blocks = min(le32_to_cpu(ext_cur->ee_block) +
+ ext4_ext_get_actual_len(ext_cur), block_end + 1) -
+ max(le32_to_cpu(ext_cur->ee_block), block_start);
+
+ while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) {
+ seq_blocks += add_blocks;
+
+ /* Adjust tail blocks */
+ if (seq_start + seq_blocks - 1 > block_end)
+ seq_blocks = block_end - seq_start + 1;
+
+ ext_prev = ext_cur;
+ last_extent = ext4_mext_next_extent(orig_inode,
+ holecheck_path, &ext_cur);
+ if (last_extent < 0) {
+ ret = last_extent;
+ break;
+ }
+ add_blocks = ext4_ext_get_actual_len(ext_cur);
+
+ /*
+ * Extend the length of contiguous block (seq_blocks)
+ * if extents are contiguous.
+ */
+ if (ext4_can_extents_be_merged(orig_inode,
+ ext_prev, ext_cur) &&
+ block_end >= le32_to_cpu(ext_cur->ee_block) &&
+ !last_extent)
+ continue;
+
+ /* Is original extent is uninitialized */
+ uninit = ext4_ext_is_uninitialized(ext_prev);
+
+ data_offset_in_page = seq_start % blocks_per_page;
+
+ /*
+ * Calculate data blocks count that should be swapped
+ * at the first page.
+ */
+ if (data_offset_in_page + seq_blocks > blocks_per_page) {
+ /* Swapped blocks are across pages */
+ block_len_in_page =
+ blocks_per_page - data_offset_in_page;
+ } else {
+ /* Swapped blocks are in a page */
+ block_len_in_page = seq_blocks;
+ }
+
+ orig_page_offset = seq_start >>
+ (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
+ seq_end_page = (seq_start + seq_blocks - 1) >>
+ (PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
+ seq_start = le32_to_cpu(ext_cur->ee_block);
+ rest_blocks = seq_blocks;
+
+ /* Discard preallocations of two inodes */
+ down_write(&EXT4_I(orig_inode)->i_data_sem);
+ ext4_discard_preallocations(orig_inode);
+ up_write(&EXT4_I(orig_inode)->i_data_sem);
+
+ down_write(&EXT4_I(donor_inode)->i_data_sem);
+ ext4_discard_preallocations(donor_inode);
+ up_write(&EXT4_I(donor_inode)->i_data_sem);
+
+ while (orig_page_offset <= seq_end_page) {
+
+ /* Swap original branches with new branches */
+ ret = ext4_mext_partial(o_filp, donor_inode,
+ orig_page_offset, data_offset_in_page,
+ block_len_in_page, uninit);
+ if (ret < 0)
+ goto out;
+ orig_page_offset++;
+
+ data_offset_in_page = 0;
+ rest_blocks -= block_len_in_page;
+ if (rest_blocks > blocks_per_page)
+ block_len_in_page = blocks_per_page;
+ else
+ block_len_in_page = rest_blocks;
+ }
+
+ /* Decrease buffer counter */
+ if (holecheck_path)
+ ext4_ext_drop_refs(holecheck_path);
+ ext4_mext_get_extpath(holecheck_path, orig_inode,
+ seq_start, ret);
+ if (holecheck_path == NULL)
+ break;
+ depth = holecheck_path->p_depth;
+
+ /* Decrease buffer counter */
+ if (orig_path)
+ ext4_ext_drop_refs(orig_path);
+ ext4_mext_get_extpath(orig_path, orig_inode, seq_start, ret);
+ if (orig_path == NULL)
+ break;
+
+ ext_cur = holecheck_path[depth].p_ext;
+ add_blocks = ext4_ext_get_actual_len(ext_cur);
+ seq_blocks = 0;
+
+ }
+out:
+ if (orig_path) {
+ ext4_ext_drop_refs(orig_path);
+ kfree(orig_path);
+ }
+ if (holecheck_path) {
+ ext4_ext_drop_refs(holecheck_path);
+ kfree(holecheck_path);
+ }
+out2:
+ ext4_mext_inode_double_unlock(orig_inode, donor_inode);
+
+ if (ret) {
+ *moved_len = orig_page_offset * blocks_per_page;
+ return ret;
+ }
+
+ /* Set moved block length */
+ *moved_len = len;
+
+ return 0;
+}
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