Btrfs: add new defrag-range ioctl.
The btrfs defrag ioctl was limited to doing the entire file. This
commit adds a new interface that can defrag a specific range inside
the file.
It can also force compression on the file, allowing you to selectively
compress individual files after they were created, even when mount -o
compress isn't turned on.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3a89cd7..d866b46 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -476,13 +476,18 @@
}
static int should_defrag_range(struct inode *inode, u64 start, u64 len,
- u64 *last_len, u64 *skip, u64 *defrag_end)
+ int thresh, u64 *last_len, u64 *skip,
+ u64 *defrag_end)
{
struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
struct extent_map *em = NULL;
struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
int ret = 1;
+
+ if (thresh == 0)
+ thresh = 256 * 1024;
+
/*
* make sure that once we start defragging and extent, we keep on
* defragging it
@@ -517,8 +522,7 @@
/*
* we hit a real extent, if it is big don't bother defragging it again
*/
- if ((*last_len == 0 || *last_len >= 256 * 1024) &&
- em->len >= 256 * 1024)
+ if ((*last_len == 0 || *last_len >= thresh) && em->len >= thresh)
ret = 0;
/*
@@ -542,7 +546,8 @@
return ret;
}
-static int btrfs_defrag_file(struct file *file)
+static int btrfs_defrag_file(struct file *file,
+ struct btrfs_ioctl_defrag_range_args *range)
{
struct inode *inode = fdentry(file)->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
@@ -563,11 +568,19 @@
if (inode->i_size == 0)
return 0;
- last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
- i = 0;
+ if (range->start + range->len > range->start) {
+ last_index = min_t(u64, inode->i_size - 1,
+ range->start + range->len - 1) >> PAGE_CACHE_SHIFT;
+ } else {
+ last_index = (inode->i_size - 1) >> PAGE_CACHE_SHIFT;
+ }
+
+ i = range->start >> PAGE_CACHE_SHIFT;
while (i <= last_index) {
if (!should_defrag_range(inode, (u64)i << PAGE_CACHE_SHIFT,
- PAGE_CACHE_SIZE, &last_len, &skip,
+ PAGE_CACHE_SIZE,
+ range->extent_thresh,
+ &last_len, &skip,
&defrag_end)) {
unsigned long next;
/*
@@ -585,6 +598,8 @@
}
total_read++;
mutex_lock(&inode->i_mutex);
+ if (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)
+ BTRFS_I(inode)->force_compress = 1;
ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
if (ret) {
@@ -673,6 +688,28 @@
i++;
}
+ if ((range->flags & BTRFS_DEFRAG_RANGE_START_IO))
+ filemap_flush(inode->i_mapping);
+
+ if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
+ /* the filemap_flush will queue IO into the worker threads, but
+ * we have to make sure the IO is actually started and that
+ * ordered extents get created before we return
+ */
+ atomic_inc(&root->fs_info->async_submit_draining);
+ while (atomic_read(&root->fs_info->nr_async_submits) ||
+ atomic_read(&root->fs_info->async_delalloc_pages)) {
+ wait_event(root->fs_info->async_submit_wait,
+ (atomic_read(&root->fs_info->nr_async_submits) == 0 &&
+ atomic_read(&root->fs_info->async_delalloc_pages) == 0));
+ }
+ atomic_dec(&root->fs_info->async_submit_draining);
+
+ mutex_lock(&inode->i_mutex);
+ BTRFS_I(inode)->force_compress = 0;
+ mutex_unlock(&inode->i_mutex);
+ }
+
return 0;
err_reservations:
@@ -1284,10 +1321,11 @@
return err;
}
-static int btrfs_ioctl_defrag(struct file *file)
+static int btrfs_ioctl_defrag(struct file *file, void __user *argp)
{
struct inode *inode = fdentry(file)->d_inode;
struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct btrfs_ioctl_defrag_range_args *range;
int ret;
ret = mnt_want_write(file->f_path.mnt);
@@ -1308,7 +1346,30 @@
ret = -EINVAL;
goto out;
}
- btrfs_defrag_file(file);
+
+ range = kzalloc(sizeof(*range), GFP_KERNEL);
+ if (!range) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (argp) {
+ if (copy_from_user(range, argp,
+ sizeof(*range))) {
+ ret = -EFAULT;
+ kfree(range);
+ }
+ /* compression requires us to start the IO */
+ if ((range->flags & BTRFS_DEFRAG_RANGE_COMPRESS)) {
+ range->flags |= BTRFS_DEFRAG_RANGE_START_IO;
+ range->extent_thresh = (u32)-1;
+ }
+ } else {
+ /* the rest are all set to zero by kzalloc */
+ range->len = (u64)-1;
+ }
+ btrfs_defrag_file(file, range);
+ kfree(range);
break;
}
out:
@@ -1831,7 +1892,9 @@
case BTRFS_IOC_DEFAULT_SUBVOL:
return btrfs_ioctl_default_subvol(file, argp);
case BTRFS_IOC_DEFRAG:
- return btrfs_ioctl_defrag(file);
+ return btrfs_ioctl_defrag(file, NULL);
+ case BTRFS_IOC_DEFRAG_RANGE:
+ return btrfs_ioctl_defrag(file, argp);
case BTRFS_IOC_RESIZE:
return btrfs_ioctl_resize(root, argp);
case BTRFS_IOC_ADD_DEV: