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Commit be6e8dc0 authored by Balaji Rao's avatar Balaji Rao Committed by Chris Mason
Browse files

NFS support for btrfs - v3 



Date: Mon, 21 Jul 2008 02:01:56 +0530
Here's an implementation of NFS support for btrfs. It relies on the
fixes which are going in to 2.6.28 for the NFS readdir/lookup deadlock.

This uses the btrfs_iget helper introduced previously.

[dwmw2: Tidy up a little, switch to d_obtain_alias() w/compat routine,
	change fh_type,	store parent's root object ID where needed,
	fix some get_parent() and fs_to_dentry() bugs]

Signed-off-by: default avatarBalaji Rao <balajirrao@gmail.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent 1a54ef8c

fs/btrfs/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -7,7 +7,7 @@ btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ 
	   transaction.o bit-radix.o inode.o file.o tree-defrag.o \

	   extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \

	   extent_io.o volumes.o async-thread.o ioctl.o locking.o orphan.o \

	   ref-cache.o

	   ref-cache.o export.o



btrfs-$(CONFIG_FS_POSIX_ACL)	+= acl.o

else

fs/btrfs/compat.h

+17 −0
Original line number Diff line number Diff line
@@ -5,6 +5,23 @@ 
#define trylock_page(page) (!TestSetPageLocked(page))

#endif



#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,27)

static inline struct dentry *d_obtain_alias(struct inode *inode)

{

	struct dentry *d;



	if (!inode)

		return NULL;

	if (IS_ERR(inode))

		return ERR_CAST(inode);



	d = d_alloc_anon(inode);

	if (!d)

		iput(inode);

	return d;

}

#endif



/*

 * Even if AppArmor isn't enabled, it still has different prototypes.

 * Add more distro/version pairs here to declare which has AppArmor applied.

fs/btrfs/export.c

0 → 100644
+208 −0
Original line number Diff line number Diff line 
#include <linux/fs.h>

#include <linux/types.h>

#include "ctree.h"

#include "disk-io.h"

#include "btrfs_inode.h"

#include "print-tree.h"

#include "export.h"

#include "compat.h"



#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)

#define FILEID_BTRFS_WITHOUT_PARENT		0x4d

#define FILEID_BTRFS_WITH_PARENT 		0x4e

#define FILEID_BTRFS_WITH_PARENT_ROOT 		0x4f

#endif



#define BTRFS_FID_SIZE_NON_CONNECTABLE		(offsetof(struct btrfs_fid, parent_objectid)/4)

#define BTRFS_FID_SIZE_CONNECTABLE		(offsetof(struct btrfs_fid, parent_root_objectid)/4)

#define BTRFS_FID_SIZE_CONNECTABLE_ROOT		(sizeof(struct btrfs_fid)/4)



static int btrfs_encode_fh(struct dentry *dentry, u32 *fh, int *max_len,

			   int connectable)

{

	struct btrfs_fid *fid = (struct btrfs_fid *)fh;

	struct inode *inode = dentry->d_inode;

	int len = *max_len;

	int type;



	if ((len < BTRFS_FID_SIZE_NON_CONNECTABLE) ||

	    (connectable && len < BTRFS_FID_SIZE_CONNECTABLE))

		return 255;



	len  = BTRFS_FID_SIZE_NON_CONNECTABLE;

	type = FILEID_BTRFS_WITHOUT_PARENT;



	fid->objectid = BTRFS_I(inode)->location.objectid;

	fid->root_objectid = BTRFS_I(inode)->root->objectid;

	fid->gen = inode->i_generation;



	if (connectable && !S_ISDIR(inode->i_mode)) {

		struct inode *parent;

		u64 parent_root_id;



		spin_lock(&dentry->d_lock);



		parent = dentry->d_parent->d_inode;

		fid->parent_objectid = BTRFS_I(parent)->location.objectid;

		fid->parent_gen = parent->i_generation;

		parent_root_id = BTRFS_I(parent)->root->objectid;



		spin_unlock(&dentry->d_lock);



		if (parent_root_id != fid->root_objectid) {

			fid->parent_root_objectid = parent_root_id;

			len = BTRFS_FID_SIZE_CONNECTABLE_ROOT;

			type = FILEID_BTRFS_WITH_PARENT_ROOT;

		} else {

			len = BTRFS_FID_SIZE_CONNECTABLE;

			type = FILEID_BTRFS_WITH_PARENT;

		}

	}



	*max_len = len;

	return type;

}



static struct dentry *btrfs_get_dentry(struct super_block *sb, u64 objectid,

				       u64 root_objectid, u32 generation)

{

	struct btrfs_root *root;

	struct inode *inode;

	struct dentry *result;

	struct btrfs_key key;



	key.objectid = objectid;

	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);

	key.offset = 0;



	root = btrfs_lookup_fs_root(btrfs_sb(sb)->fs_info, root_objectid);

	inode = btrfs_iget(sb, &key, root, NULL);

	if (IS_ERR(inode))

		return (void *)inode;



	if (generation != inode->i_generation) {

		iput(inode);

		return ERR_PTR(-ESTALE);

	}



	result = d_obtain_alias(inode);

	if (!result)

		return ERR_PTR(-ENOMEM);



	return result;

}



static struct dentry *btrfs_fh_to_parent(struct super_block *sb, struct fid *fh,

					 int fh_len, int fh_type)

{

	struct btrfs_fid *fid = (struct btrfs_fid *) fh;

	u64 objectid, root_objectid;

	u32 generation;



	if (fh_type == FILEID_BTRFS_WITH_PARENT) {

		if (fh_len !=  BTRFS_FID_SIZE_CONNECTABLE)

			return NULL;

		root_objectid = fid->root_objectid;

	} else if (fh_type == FILEID_BTRFS_WITH_PARENT_ROOT) {

		if (fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT)

			return NULL;

		root_objectid = fid->parent_root_objectid;

	} else

		return NULL;



	objectid = fid->parent_objectid;

	generation = fid->parent_gen;



	return btrfs_get_dentry(sb, objectid, root_objectid, generation);

}



static struct dentry *btrfs_fh_to_dentry(struct super_block *sb, struct fid *fh,

					 int fh_len, int fh_type)

{

	struct btrfs_fid *fid = (struct btrfs_fid *) fh;

	u64 objectid, root_objectid;

	u32 generation;



	if ((fh_type != FILEID_BTRFS_WITH_PARENT ||

	     fh_len != BTRFS_FID_SIZE_CONNECTABLE) &&

	    (fh_type != FILEID_BTRFS_WITH_PARENT_ROOT ||

	     fh_len != BTRFS_FID_SIZE_CONNECTABLE_ROOT) &&

	    (fh_type != FILEID_BTRFS_WITHOUT_PARENT ||

	     fh_len != BTRFS_FID_SIZE_NON_CONNECTABLE))

		return NULL;



	objectid = fid->objectid;

	root_objectid = fid->root_objectid;

	generation = fid->gen;



	return btrfs_get_dentry(sb, objectid, root_objectid, generation);

}



static struct dentry *btrfs_get_parent(struct dentry *child)

{

	struct inode *dir = child->d_inode;

	struct inode *inode;

	struct dentry *parent;

	struct btrfs_root *root = BTRFS_I(dir)->root;

	struct btrfs_key key;

	struct btrfs_path *path;

	struct extent_buffer *leaf;

	u32 nritems;

	int slot;

	u64 objectid;

	int ret;



	path = btrfs_alloc_path();



	key.objectid = dir->i_ino;

	btrfs_set_key_type(&key, BTRFS_INODE_REF_KEY);

	key.offset = 0;

	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);

	BUG_ON(ret == 0);

	ret = 0;



	leaf = path->nodes[0];

	slot = path->slots[0];

	nritems = btrfs_header_nritems(leaf);

	if (slot >= nritems) {

		ret = btrfs_next_leaf(root, path);

		if (ret) {

			btrfs_free_path(path);

			goto out;

		}

		leaf = path->nodes[0];

		slot = path->slots[0];

	}



	btrfs_free_path(path);



	btrfs_item_key_to_cpu(leaf, &key, slot);

	if (key.objectid != dir->i_ino || key.type != BTRFS_INODE_REF_KEY)

		goto out;



	objectid = key.offset;



	/* Build a new key for the inode item */

	key.objectid = objectid;

	btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);

	key.offset = 0;



	inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);



	parent = d_obtain_alias(inode);

	if (!parent)

		parent = ERR_PTR(-ENOMEM);



	return parent;



out:

	btrfs_free_path(path);

	return ERR_PTR(-EINVAL);

}



const struct export_operations btrfs_export_ops = {

	.encode_fh	= btrfs_encode_fh,

	.fh_to_dentry	= btrfs_fh_to_dentry,

	.fh_to_parent	= btrfs_fh_to_parent,

	.get_parent	= btrfs_get_parent,

};

fs/btrfs/export.h

0 → 100644
+19 −0
Original line number Diff line number Diff line 
#ifndef BTRFS_EXPORT_H

#define BTRFS_EXPORT_H



#include <linux/exportfs.h>



extern const struct export_operations btrfs_export_ops;



struct btrfs_fid {

	u64 objectid;

	u64 root_objectid;

	u32 gen;



	u64 parent_objectid;

	u32 parent_gen;



	u64 parent_root_objectid;

} __attribute__ ((packed));



#endif

fs/btrfs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -46,6 +46,7 @@ 
#include "xattr.h"

#include "volumes.h"

#include "version.h"

#include "export.h"



#define BTRFS_SUPER_MAGIC 0x9123683E
@@ -303,6 +304,7 @@ static int btrfs_fill_super(struct super_block * sb, 
	sb->s_maxbytes = MAX_LFS_FILESIZE;

	sb->s_magic = BTRFS_SUPER_MAGIC;

	sb->s_op = &btrfs_super_ops;

	sb->s_export_op = &btrfs_export_ops;

	sb->s_xattr = btrfs_xattr_handlers;

	sb->s_time_gran = 1;

	sb->s_flags |= MS_POSIXACL;