Commit c59f8951 authored by Chris Mason's avatar Chris Mason
Browse files

Btrfs: Add mount option to enforce a max extent size 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent d10c5f31

fs/btrfs/ctree.h

+1 −0
Original line number Diff line number Diff line
@@ -322,6 +322,7 @@ struct btrfs_fs_info { 
	u64 generation;

	u64 last_trans_committed;

	unsigned long mount_opt;

	u64 max_extent;

	struct btrfs_transaction *running_transaction;

	struct btrfs_super_block super_copy;

	struct extent_buffer *sb_buffer;

fs/btrfs/disk-io.c

+1 −0
Original line number Diff line number Diff line
@@ -569,6 +569,7 @@ struct btrfs_root *open_ctree(struct super_block *sb) 
	fs_info->extent_root = extent_root;

	fs_info->sb = sb;

	fs_info->mount_opt = 0;

	fs_info->max_extent = (u64)-1;

	fs_info->btree_inode = new_inode(sb);

	fs_info->btree_inode->i_ino = 1;

	fs_info->btree_inode->i_nlink = 1;

fs/btrfs/inode.c

+18 −10
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end) 
	struct btrfs_trans_handle *trans;

	u64 alloc_hint = 0;

	u64 num_bytes;

	u64 cur_alloc_size;

	u64 blocksize = root->sectorsize;

	struct btrfs_key ins;

	int ret;
@@ -94,8 +95,11 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end) 
	if (alloc_hint == EXTENT_MAP_INLINE)

		goto out;



	ret = btrfs_alloc_extent(trans, root, num_bytes,

				 root->root_key.objectid, trans->transid,

	while(num_bytes > 0) {

		cur_alloc_size = min(num_bytes, root->fs_info->max_extent);

		ret = btrfs_alloc_extent(trans, root, cur_alloc_size,

					 root->root_key.objectid,

					 trans->transid,

					 inode->i_ino, start, 0,

					 alloc_hint, (u64)-1, &ins, 1);

		if (ret) {
@@ -105,6 +109,10 @@ static int cow_file_range(struct inode *inode, u64 start, u64 end) 
		ret = btrfs_insert_file_extent(trans, root, inode->i_ino,

					       start, ins.objectid, ins.offset,

					       ins.offset);

		num_bytes -= cur_alloc_size;

		alloc_hint = ins.objectid + ins.offset;

		start += cur_alloc_size;

	}

out:

	btrfs_end_transaction(trans, root);

	return ret;

fs/btrfs/super.c

+45 −1
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <linux/statfs.h>

#include <linux/compat.h>

#include <linux/parser.h>

#include <linux/ctype.h>

#include "ctree.h"

#include "disk-io.h"

#include "transaction.h"
@@ -61,16 +62,42 @@ static void btrfs_put_super (struct super_block * sb) 
}



enum {

	Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_err,

	Opt_subvol, Opt_nodatasum, Opt_nodatacow, Opt_max_extent, Opt_err,

};



static match_table_t tokens = {

	{Opt_subvol, "subvol=%s"},

	{Opt_nodatasum, "nodatasum"},

	{Opt_nodatacow, "nodatacow"},

	{Opt_max_extent, "max_extent=%s"},

	{Opt_err, NULL}

};



static unsigned long parse_size(char *str)

{

	unsigned long res;

	int mult = 1;

	char *end;

	char last;



	res = simple_strtoul(str, &end, 10);



	last = end[0];

	if (isalpha(last)) {

		last = tolower(last);

		switch (last) {

		case 'g':

			mult *= 1024;

		case 'm':

			mult *= 1024;

		case 'k':

			mult *= 1024;

		}

		res = res * mult;

	}

	return res;

}



static int parse_options (char * options,

			  struct btrfs_root *root,

			  char **subvol_name)
@@ -118,6 +145,21 @@ static int parse_options (char * options, 
				btrfs_set_opt(info->mount_opt, NODATASUM);

			}

			break;

		case Opt_max_extent:

			if (info) {

				char *num = match_strdup(&args[0]);

				if (num) {

					info->max_extent = parse_size(num);

					kfree(num);



					info->max_extent = max_t(u64,

							 info->max_extent,

							 root->sectorsize);

					printk("btrfs: max_extent at %Lu\n",

					       info->max_extent);

				}

			}

			break;

		default:

			break;

		}
@@ -329,6 +371,8 @@ static int btrfs_get_sb(struct file_system_type *fs_type, 
	ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data,

			btrfs_fill_super, mnt,

			subvol_name ? subvol_name : "default");

	if (subvol_name)

		kfree(subvol_name);

	return ret;

}