btrfs: move the auto defrag code to defrag.c

This currently exists in file.c, move it to the more natural location in
defrag.c.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ reformat comments ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 337 insertions, 0 deletions

diff --git a/fs/btrfs/defrag.c b/fs/btrfs/defrag.c
index 5df604846de6..4c8c03185ce7 100644
--- a/fs/btrfs/defrag.c
+++ b/fs/btrfs/defrag.c
@@ -11,6 +11,326 @@
 #include "locking.h"
 #include "accessors.h"
 
+static struct kmem_cache *btrfs_inode_defrag_cachep;
+
+/*
+ * When auto defrag is enabled we queue up these defrag structs to remember
+ * which inodes need defragging passes.
+ */
+struct inode_defrag {
+	struct rb_node rb_node;
+	/* Inode number */
+	u64 ino;
+	/*
+	 * Transid where the defrag was added, we search for extents newer than
+	 * this.
+	 */
+	u64 transid;
+
+	/* Root objectid */
+	u64 root;
+
+	/*
+	 * The extent size threshold for autodefrag.
+	 *
+	 * This value is different for compressed/non-compressed extents, thus
+	 * needs to be passed from higher layer.
+	 * (aka, inode_should_defrag())
+	 */
+	u32 extent_thresh;
+};
+
+static int __compare_inode_defrag(struct inode_defrag *defrag1,
+				  struct inode_defrag *defrag2)
+{
+	if (defrag1->root > defrag2->root)
+		return 1;
+	else if (defrag1->root < defrag2->root)
+		return -1;
+	else if (defrag1->ino > defrag2->ino)
+		return 1;
+	else if (defrag1->ino < defrag2->ino)
+		return -1;
+	else
+		return 0;
+}
+
+/*
+ * Pop a record for an inode into the defrag tree.  The lock must be held
+ * already.
+ *
+ * If you're inserting a record for an older transid than an existing record,
+ * the transid already in the tree is lowered.
+ *
+ * If an existing record is found the defrag item you pass in is freed.
+ */
+static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
+				    struct inode_defrag *defrag)
+{
+	struct btrfs_fs_info *fs_info = inode->root->fs_info;
+	struct inode_defrag *entry;
+	struct rb_node **p;
+	struct rb_node *parent = NULL;
+	int ret;
+
+	p = &fs_info->defrag_inodes.rb_node;
+	while (*p) {
+		parent = *p;
+		entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+		ret = __compare_inode_defrag(defrag, entry);
+		if (ret < 0)
+			p = &parent->rb_left;
+		else if (ret > 0)
+			p = &parent->rb_right;
+		else {
+			/*
+			 * If we're reinserting an entry for an old defrag run,
+			 * make sure to lower the transid of our existing
+			 * record.
+			 */
+			if (defrag->transid < entry->transid)
+				entry->transid = defrag->transid;
+			entry->extent_thresh = min(defrag->extent_thresh,
+						   entry->extent_thresh);
+			return -EEXIST;
+		}
+	}
+	set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
+	rb_link_node(&defrag->rb_node, parent, p);
+	rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
+	return 0;
+}
+
+static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
+{
+	if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
+		return 0;
+
+	if (btrfs_fs_closing(fs_info))
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Insert a defrag record for this inode if auto defrag is enabled.
+ */
+int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
+			   struct btrfs_inode *inode, u32 extent_thresh)
+{
+	struct btrfs_root *root = inode->root;
+	struct btrfs_fs_info *fs_info = root->fs_info;
+	struct inode_defrag *defrag;
+	u64 transid;
+	int ret;
+
+	if (!__need_auto_defrag(fs_info))
+		return 0;
+
+	if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
+		return 0;
+
+	if (trans)
+		transid = trans->transid;
+	else
+		transid = inode->root->last_trans;
+
+	defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
+	if (!defrag)
+		return -ENOMEM;
+
+	defrag->ino = btrfs_ino(inode);
+	defrag->transid = transid;
+	defrag->root = root->root_key.objectid;
+	defrag->extent_thresh = extent_thresh;
+
+	spin_lock(&fs_info->defrag_inodes_lock);
+	if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
+		/*
+		 * If we set IN_DEFRAG flag and evict the inode from memory,
+		 * and then re-read this inode, this new inode doesn't have
+		 * IN_DEFRAG flag. At the case, we may find the existed defrag.
+		 */
+		ret = __btrfs_add_inode_defrag(inode, defrag);
+		if (ret)
+			kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+	} else {
+		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+	}
+	spin_unlock(&fs_info->defrag_inodes_lock);
+	return 0;
+}
+
+/*
+ * Pick the defragable inode that we want, if it doesn't exist, we will get the
+ * next one.
+ */
+static struct inode_defrag *btrfs_pick_defrag_inode(
+			struct btrfs_fs_info *fs_info, u64 root, u64 ino)
+{
+	struct inode_defrag *entry = NULL;
+	struct inode_defrag tmp;
+	struct rb_node *p;
+	struct rb_node *parent = NULL;
+	int ret;
+
+	tmp.ino = ino;
+	tmp.root = root;
+
+	spin_lock(&fs_info->defrag_inodes_lock);
+	p = fs_info->defrag_inodes.rb_node;
+	while (p) {
+		parent = p;
+		entry = rb_entry(parent, struct inode_defrag, rb_node);
+
+		ret = __compare_inode_defrag(&tmp, entry);
+		if (ret < 0)
+			p = parent->rb_left;
+		else if (ret > 0)
+			p = parent->rb_right;
+		else
+			goto out;
+	}
+
+	if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
+		parent = rb_next(parent);
+		if (parent)
+			entry = rb_entry(parent, struct inode_defrag, rb_node);
+		else
+			entry = NULL;
+	}
+out:
+	if (entry)
+		rb_erase(parent, &fs_info->defrag_inodes);
+	spin_unlock(&fs_info->defrag_inodes_lock);
+	return entry;
+}
+
+void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+	struct inode_defrag *defrag;
+	struct rb_node *node;
+
+	spin_lock(&fs_info->defrag_inodes_lock);
+	node = rb_first(&fs_info->defrag_inodes);
+	while (node) {
+		rb_erase(node, &fs_info->defrag_inodes);
+		defrag = rb_entry(node, struct inode_defrag, rb_node);
+		kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+
+		cond_resched_lock(&fs_info->defrag_inodes_lock);
+
+		node = rb_first(&fs_info->defrag_inodes);
+	}
+	spin_unlock(&fs_info->defrag_inodes_lock);
+}
+
+#define BTRFS_DEFRAG_BATCH	1024
+
+static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
+				    struct inode_defrag *defrag)
+{
+	struct btrfs_root *inode_root;
+	struct inode *inode;
+	struct btrfs_ioctl_defrag_range_args range;
+	int ret = 0;
+	u64 cur = 0;
+
+again:
+	if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
+		goto cleanup;
+	if (!__need_auto_defrag(fs_info))
+		goto cleanup;
+
+	/* Get the inode */
+	inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
+	if (IS_ERR(inode_root)) {
+		ret = PTR_ERR(inode_root);
+		goto cleanup;
+	}
+
+	inode = btrfs_iget(fs_info->sb, defrag->ino, inode_root);
+	btrfs_put_root(inode_root);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
+		goto cleanup;
+	}
+
+	if (cur >= i_size_read(inode)) {
+		iput(inode);
+		goto cleanup;
+	}
+
+	/* Do a chunk of defrag */
+	clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
+	memset(&range, 0, sizeof(range));
+	range.len = (u64)-1;
+	range.start = cur;
+	range.extent_thresh = defrag->extent_thresh;
+
+	sb_start_write(fs_info->sb);
+	ret = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
+				       BTRFS_DEFRAG_BATCH);
+	sb_end_write(fs_info->sb);
+	iput(inode);
+
+	if (ret < 0)
+		goto cleanup;
+
+	cur = max(cur + fs_info->sectorsize, range.start);
+	goto again;
+
+cleanup:
+	kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
+	return ret;
+}
+
+/*
+ * Run through the list of inodes in the FS that need defragging.
+ */
+int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
+{
+	struct inode_defrag *defrag;
+	u64 first_ino = 0;
+	u64 root_objectid = 0;
+
+	atomic_inc(&fs_info->defrag_running);
+	while (1) {
+		/* Pause the auto defragger. */
+		if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
+			break;
+
+		if (!__need_auto_defrag(fs_info))
+			break;
+
+		/* find an inode to defrag */
+		defrag = btrfs_pick_defrag_inode(fs_info, root_objectid, first_ino);
+		if (!defrag) {
+			if (root_objectid || first_ino) {
+				root_objectid = 0;
+				first_ino = 0;
+				continue;
+			} else {
+				break;
+			}
+		}
+
+		first_ino = defrag->ino + 1;
+		root_objectid = defrag->root;
+
+		__btrfs_run_defrag_inode(fs_info, defrag);
+	}
+	atomic_dec(&fs_info->defrag_running);
+
+	/*
+	 * During unmount, we use the transaction_wait queue to wait for the
+	 * defragger to stop.
+	 */
+	wake_up(&fs_info->transaction_wait);
+	return 0;
+}
+
 /*
  * Defrag all the leaves in a given btree.
  * Read all the leaves and try to get key order to
@@ -131,3 +451,20 @@ done:
 
 	return ret;
 }
+
+void __cold btrfs_auto_defrag_exit(void)
+{
+	kmem_cache_destroy(btrfs_inode_defrag_cachep);
+}
+
+int __init btrfs_auto_defrag_init(void)
+{
+	btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
+					sizeof(struct inode_defrag), 0,
+					SLAB_MEM_SPREAD,
+					NULL);
+	if (!btrfs_inode_defrag_cachep)
+		return -ENOMEM;
+
+	return 0;
+}