ext4: online defrag-- Check the free space fragmentation (-f mode)
From: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
Check the free space fragmentation in the block group
where target file is located.
Signed-off-by: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
Signed-off-by: Takashi Sato <t-sato@xxxxxxxxxxxxx>
---
fs/ext4/balloc.c | 2 +-
fs/ext4/defrag.c | 270 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/ext4.h | 34 +++++++
fs/ext4/ioctl.c | 5 +-
4 files changed, 309 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 999f9e2..49b099c 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -869,7 +869,7 @@ static int ext4_test_allocatable(ext4_grpblk_t nr, struct buffer_head *bh)
* bitmap on disk and the last-committed copy in journal, until we find a
* bit free in both bitmaps.
*/
-static ext4_grpblk_t
+ext4_grpblk_t
bitmap_search_next_usable_block(ext4_grpblk_t start, struct buffer_head *bh,
ext4_grpblk_t maxblocks)
{
diff --git a/fs/ext4/defrag.c b/fs/ext4/defrag.c
index 847f708..6b6b873 100644
--- a/fs/ext4/defrag.c
+++ b/fs/ext4/defrag.c
@@ -20,6 +20,12 @@
#include "ext4_extents.h"
#include "group.h"
+#define EXT_SET_EXTENT_DATA(src, dest) do { \
+ dest.block = le32_to_cpu(src->ee_block); \
+ dest.start = ext_pblock(src); \
+ dest.len = le16_to_cpu(src->ee_len); \
+ } while (0)
+
/**
* ext4_defrag_next_extent - Search for the next extent and set it to "extent"
*
@@ -89,6 +95,224 @@ ext4_defrag_next_extent(struct inode *inode,
return 1;
}
+/**
+ * ext4_defrag_extents_info - Get extents information
+ *
+ * @sb: for ext4_iget()
+ * @ext_info: pointer to ext4_extents_info
+ * @ext_info->ino describe an inode which is used to get
+ * extent information
+ * @ext_info->max_entries: defined by DEFRAG_MAX_ENT
+ * @ext_info->entries: amount of extents (output)
+ * @ext_info->ext[]: array of extent (output)
+ * @ext_info->offset: starting block offset of targeted extent
+ * (file relative)
+ *
+ * This function returns 0 if the next extent(s) exists,
+ * or returns 1 if the next extent doesn't exist,
+ * otherwise returns error value.
+ */
+static int ext4_defrag_extents_info(struct super_block *sb,
+ struct ext4_extents_info *ext_info)
+{
+ struct ext4_ext_path *path = NULL;
+ struct ext4_extent *ext = NULL;
+ struct inode *inode = NULL;
+ ext4_lblk_t offset = ext_info->f_offset;
+ int max_entries = ext_info->max_entries;
+ int depth = 0;
+ int entries = 0;
+ int err = 0;
+ int ret = 0;
+
+ inode = ext4_iget(sb, ext_info->ino);
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+
+ down_write(&EXT4_I(inode)->i_data_sem);
+
+ /* Return -ENOENT if a file does not exist */
+ if ((!inode->i_nlink) || (inode->i_ino < 11) ||
+ !S_ISREG(inode->i_mode)) {
+ ext_info->entries = 0;
+ err = -ENOENT;
+ goto out;
+ }
+
+ path = ext4_ext_find_extent(inode, offset, NULL);
+ if (IS_ERR(path)) {
+ err = PTR_ERR(path);
+ path = NULL;
+ goto out;
+ }
+ depth = ext_depth(inode);
+
+ /* Skip the 0 size file */
+ if (path[depth].p_ext == NULL) {
+ ext_info->entries = 0;
+ goto out;
+ }
+ ext = path[depth].p_ext;
+ EXT_SET_EXTENT_DATA(ext, ext_info->ext[entries]);
+ entries = 1;
+
+ /*
+ * The ioctl repeats this loop 'max_entries' times.
+ * So we have to call this function again if @inode had
+ * more the number of extents than 'max_entries'.
+ */
+ while (entries < max_entries) {
+ ret = ext4_defrag_next_extent(inode, path, &ext);
+ if (ret == 0) {
+ /* Found the next extent (it means not the last one) */
+ EXT_SET_EXTENT_DATA(ext, ext_info->ext[entries]);
+ entries++;
+
+ /*
+ * In case @inode has > 'max_entries' extents,
+ * we must call this function again and restart from
+ * 'max_entries * n + 1'th extent.
+ * 'n' is the number of calling this function
+ * at the same @inode.
+ */
+ if (entries == max_entries) {
+ ext_info->f_offset =
+ le32_to_cpu(ext->ee_block) +
+ le16_to_cpu(ext->ee_len);
+ /* Check the extent is the last one or not */
+ ret =
+ ext4_defrag_next_extent(inode, path, &ext);
+ if (ret == 1) {
+ err = ret;
+ } else if (ret < 0) {
+ /* Failed to get the next extent */
+ err = ret;
+ goto out;
+ }
+ break;
+ }
+
+ } else if (ret == 1) {
+ /* The extent is the last one */
+ ext_info->f_offset = 0;
+ err = ret;
+ break;
+ } else {
+ /* Failed to get the next extent */
+ err = ret;
+ goto out;
+ }
+ }
+
+ ext_info->entries = entries;
+
+out:
+ if (path) {
+ ext4_ext_drop_refs(path);
+ kfree(path);
+ }
+ up_write(&EXT4_I(inode)->i_data_sem);
+ iput(inode);
+ return err;
+}
+
+/**
+ * ext4_defrag_fblocks_distribution - Search free blocks distribution
+ *
+ * @inode target file
+ * @ext_info ext4_extents_info
+ *
+ * This function returns 0 if succeeded, otherwise
+ * returns error value.
+ */
+static int ext4_defrag_fblocks_distribution(struct inode *inode,
+ struct ext4_extents_info *ext_info)
+{
+ struct buffer_head *bitmap_bh = NULL;
+ struct super_block *sb = inode->i_sb;
+ handle_t *handle;
+ ext4_group_t group_no;
+ ext4_grpblk_t start, end;
+ ext4_fsblk_t start_block = 0;
+ int num = 0;
+ int len = 0;
+ int i = 0;
+ int err = 0;
+ int block_set = 0;
+ int extra_block = 0;
+
+ if (!sb) {
+ printk(KERN_ERR "ext4 defrag: Non-existent device\n");
+ return -ENOSPC;
+ }
+
+ group_no = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(sb);
+ start = ext_info->g_offset;
+ end = EXT4_BLOCKS_PER_GROUP(sb) - 1;
+
+ /* We consider about the boot block if bs = 1k */
+ if (sb->s_blocksize == 1024)
+ extra_block = 1;
+
+ handle = ext4_journal_start(inode, 1);
+ if (IS_ERR(handle)) {
+ err = PTR_ERR(handle);
+ return err;
+ }
+
+ bitmap_bh = read_block_bitmap(sb, group_no);
+ if (!bitmap_bh) {
+ err = -EIO;
+ goto out;
+ }
+
+ BUFFER_TRACE(bitmap_bh, "get undo access for new block");
+ err = ext4_journal_get_undo_access(handle, bitmap_bh);
+ if (err)
+ goto out;
+
+ for (i = start; i <= end ; i++) {
+ if (bitmap_search_next_usable_block(i, bitmap_bh, i + 1) >= 0) {
+ len++;
+ /*
+ * Reset start_block if the free block is
+ * the head of region.
+ */
+ if (!block_set) {
+ start_block =
+ i + group_no * EXT4_BLOCKS_PER_GROUP(sb) +
+ extra_block;
+ block_set = 1;
+ }
+ } else if (len) {
+ ext_info->ext[num].start = start_block;
+ ext_info->ext[num].len = len;
+ num++;
+ len = 0;
+ block_set = 0;
+ if (num == ext_info->max_entries) {
+ ext_info->g_offset = i + 1;
+ break;
+ }
+ }
+ if ((i == end) && len) {
+ ext_info->ext[num].start = start_block;
+ ext_info->ext[num].len = len;
+ num++;
+ }
+ }
+
+ ext_info->entries = num;
+out:
+ ext4_journal_release_buffer(handle, bitmap_bh);
+ brelse(bitmap_bh);
+
+ if (handle)
+ ext4_journal_stop(handle);
+
+ return err;
+}
+
int ext4_defrag_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
unsigned long arg)
{
@@ -109,6 +333,52 @@ int ext4_defrag_ioctl(struct inode *inode, struct file *filp, unsigned int cmd,
block = ext4_bmap(mapping, block);
return put_user(block, p);
+ } else if (cmd == EXT4_IOC_GROUP_INFO) {
+ struct ext4_group_data_info grp_data;
+
+ if (copy_from_user(&grp_data,
+ (struct ext4_group_data_info __user *)arg,
+ sizeof(grp_data)))
+ return -EFAULT;
+
+ grp_data.s_blocks_per_group =
+ EXT4_BLOCKS_PER_GROUP(inode->i_sb);
+ grp_data.s_inodes_per_group =
+ EXT4_INODES_PER_GROUP(inode->i_sb);
+
+ if (copy_to_user((struct ext4_group_data_info __user *)arg,
+ &grp_data, sizeof(grp_data)))
+ return -EFAULT;
+ } else if (cmd == EXT4_IOC_FREE_BLOCKS_INFO) {
+ struct ext4_extents_info ext_info;
+
+ if (copy_from_user(&ext_info,
+ (struct ext4_extents_info __user *)arg,
+ sizeof(ext_info)))
+ return -EFAULT;
+
+ BUG_ON(ext_info.ino != inode->i_ino);
+
+ err = ext4_defrag_fblocks_distribution(inode, &ext_info);
+
+ if (!err)
+ err = copy_to_user(
+ (struct ext4_extents_info __user *)arg,
+ &ext_info, sizeof(ext_info));
+ } else if (cmd == EXT4_IOC_EXTENTS_INFO) {
+ struct ext4_extents_info ext_info;
+
+ if (copy_from_user(&ext_info,
+ (struct ext4_extents_info __user *)arg,
+ sizeof(ext_info)))
+ return -EFAULT;
+
+ err = ext4_defrag_extents_info(inode->i_sb, &ext_info);
+ if (err >= 0) {
+ if (copy_to_user((struct ext4_extents_info __user *)arg,
+ &ext_info, sizeof(ext_info)))
+ return -EFAULT;
+ }
} else if (cmd == EXT4_IOC_DEFRAG) {
struct ext4_ext_defrag_data defrag;
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 24c7144..ad553e1 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -300,6 +300,9 @@ struct ext4_new_group_data {
#define EXT4_IOC_MIGRATE _IO('f', 7)
#define EXT4_IOC_FIBMAP _IOW('f', 9, ext4_fsblk_t)
#define EXT4_IOC_DEFRAG _IOW('f', 10, struct ext4_ext_defrag_data)
+#define EXT4_IOC_GROUP_INFO _IOW('f', 11, struct ext4_group_data_info)
+#define EXT4_IOC_FREE_BLOCKS_INFO _IOW('f', 12, struct ext4_extents_info)
+#define EXT4_IOC_EXTENTS_INFO _IOW('f', 13, struct ext4_extents_info)
/*
* ioctl commands in 32 bit emulation
@@ -323,12 +326,41 @@ struct ext4_new_group_data {
*/
#define DEFRAG_BLOCK_SIZE 4096
+/*
+ * The following four macros are used for the defrag force mode.
+ *
+ * DEFRAG_MAX_ENT: the maximum number of extents for exchanging between
+ * kernel-space and user-space per an ioctl
+ */
+#define DEFRAG_MAX_ENT 32
+
+struct ext4_extent_data {
+ ext4_lblk_t block; /* start logical block number */
+ ext4_fsblk_t start; /* start physical block number */
+ int len; /* blocks count */
+};
+
struct ext4_ext_defrag_data {
ext4_lblk_t start_offset; /* start offset to defrag in blocks */
ext4_lblk_t defrag_size; /* size of defrag in blocks */
ext4_fsblk_t goal; /* block offset for allocation */
};
+struct ext4_group_data_info {
+ int s_blocks_per_group; /* blocks per group */
+ int s_inodes_per_group; /* inodes per group */
+};
+
+struct ext4_extents_info {
+ unsigned long long ino; /* inode number */
+ int max_entries; /* maximum extents count */
+ int entries; /* extent number/count */
+ ext4_lblk_t f_offset; /* file offset */
+ ext4_grpblk_t g_offset; /* group offset */
+ ext4_fsblk_t goal; /* block offset for allocation */
+ struct ext4_extent_data ext[DEFRAG_MAX_ENT];
+};
+
#define EXT4_TRANS_META_BLOCKS 4 /* bitmap + group desc + sb + inode */
/*
@@ -1005,6 +1037,8 @@ extern struct ext4_group_desc * ext4_get_group_desc(struct super_block * sb,
extern int ext4_should_retry_alloc(struct super_block *sb, int *retries);
extern void ext4_init_block_alloc_info(struct inode *);
extern void ext4_rsv_window_add(struct super_block *sb, struct ext4_reserve_window_node *rsv);
+extern ext4_grpblk_t bitmap_search_next_usable_block(ext4_grpblk_t,
+ struct buffer_head *, ext4_grpblk_t);
/* dir.c */
extern int ext4_check_dir_entry(const char *, struct inode *,
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index da13cee..f216caa 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -232,7 +232,10 @@ flags_err:
return err;
}
case EXT4_IOC_FIBMAP:
- case EXT4_IOC_DEFRAG: {
+ case EXT4_IOC_DEFRAG:
+ case EXT4_IOC_GROUP_INFO:
+ case EXT4_IOC_FREE_BLOCKS_INFO:
+ case EXT4_IOC_EXTENTS_INFO: {
return ext4_defrag_ioctl(inode, filp, cmd, arg);
}
case EXT4_IOC_GROUP_ADD: {
--
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