Commit 34088780 authored by Chris Mason's avatar Chris Mason Committed by David Woodhouse
Browse files

Btrfs: i386 fixes from axboe 



Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 6cbd5570

fs/btrfs/INSTALL

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Install Instructions



Btrfs puts snapshots and subvolumes into the root directory of the FS.  This

directory can only be changed by btrfsctl right now, and normal filesystem

operations do not work on it.  The default subvolume is called 'default',

and you can create files and directories in mount_point/default



Btrfs uses the crypto manager interface in the kernel for file and

metadata checksums.  You need to compile the kernel with:



CONFIG_CRYPTO=y

CONFIG_CRYPTO_MANAGER=m

CONFIG_CRYPTO_CRC32C=m



cryptomanager and crc32c can be static as well.  Once your kernel is

setup, typing make in the btrfs module sources will build against the

running kernel.  When the build is complete:



modprobe crc32c

modprobe cryptomgr

insmod btrfs.ko



The Btrfs utility programs require libuuid to build.  This can be found

in the e2fsprogs sources, and is usually available as libuuid or

e2fsprogs-devel from various distros.



Building the utilities is just make ; make install.  The programs go

into /usr/local/bin.  The commands available are:



mkfs.btrfs: create a filesystem



btrfsctl: control program to create snapshots and subvolumes:



	mount /dev/sda2 /mnt

	btrfsctl -s new_subvol_name /mnt

	btrfsctl -s snapshot_of_default /mnt/default

	btrfsctl -s snapshot_of_new_subvol /mnt/new_subvol_name

	btrfsctl -s snapshot_of_a_snapshot /mnt/snapshot_of_new_subvol

	ls /mnt

	default snapshot_of_a_snapshot snapshot_of_new_subvol

	new_subvol_name snapshot_of_default



	Snapshots and subvolumes cannot be deleted right now, but you can

	rm -rf all the files and directories inside them.



btrfsck: do a limited check of the FS extent trees.</li>



debug-tree: print all of the FS metadata in text form.  Example:



	debug-tree /dev/sda2 >& big_output_file

fs/btrfs/disk-io.c

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@@ -106,7 +106,7 @@ struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root, 
	int err;

	u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);



	page = grab_cache_page(mapping, index);

	page = find_or_create_page(mapping, index, GFP_NOFS);

	if (!page)

		return NULL;

fs/btrfs/file.c

+5 −2
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@@ -112,7 +112,7 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans, 
		if (buffer_mapped(bh) && bh->b_blocknr == 0) {

			struct btrfs_key key;

			struct btrfs_path *path;

			char *ptr;

			char *ptr, *kaddr;

			u32 datasize;



			/* create an inline extent, and copy the data in */
@@ -135,8 +135,11 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans, 
			btrfs_set_file_extent_type(ei,

						   BTRFS_FILE_EXTENT_INLINE);

			ptr = btrfs_file_extent_inline_start(ei);

			kaddr = kmap_atomic(bh->b_page, KM_USER0);

			btrfs_memcpy(root, path->nodes[0]->b_data,

				     ptr, bh->b_data, offset + write_bytes);

				     ptr, kaddr + bh_offset(bh),

				     offset + write_bytes);

			kunmap_atomic(kaddr, KM_USER0);

			mark_buffer_dirty(path->nodes[0]);

			btrfs_free_path(path);

		} else if (buffer_mapped(bh)) {

fs/btrfs/inode.c

+1 −2
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@@ -1754,6 +1754,7 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen) 
				BTRFS_I(dir)->block_group, S_IFDIR | 0700);

	inode->i_op = &btrfs_dir_inode_operations;

	inode->i_fop = &btrfs_dir_file_operations;

	new_root->inode = inode;



	ret = btrfs_make_empty_dir(trans, new_root, new_dirid, new_dirid);

	BUG_ON(ret);
@@ -1766,8 +1767,6 @@ static int create_subvol(struct btrfs_root *root, char *name, int namelen) 
	ret = btrfs_commit_transaction(trans, new_root);

	BUG_ON(ret);



	iput(inode);



	mutex_unlock(&root->fs_info->fs_mutex);

	btrfs_btree_balance_dirty(root);

	return 0;

fs/btrfs/transaction.c

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@@ -18,6 +18,7 @@ 


#include <linux/module.h>

#include <linux/fs.h>

#include <linux/sched.h>

#include "ctree.h"

#include "disk-io.h"

#include "transaction.h"