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linux-2.6/fs/exofs/exofs.h
Boaz Harrosh 04dc1e88ad exofs: Multi-device mirror support 
This patch changes on-disk format, it is accompanied with a parallel
patch to mkfs.exofs that enables multi-device capabilities.

After this patch, old exofs will refuse to mount a new formatted FS and
new exofs will refuse an old format. This is done by moving the magic
field offset inside the FSCB. A new FSCB *version* field was added. In
the future, exofs will refuse to mount unmatched FSCB version. To
up-grade or down-grade an exofs one must use mkfs.exofs --upgrade option
before mounting.

Introduced, a new object that contains a *device-table*. This object
contains the default *data-map* and a linear array of devices
information, which identifies the devices used in the filesystem. This
object is only written to offline by mkfs.exofs. This is why it is kept
separate from the FSCB, since the later is written to while mounted.

Same partition number, same object number is used on all devices only
the device varies.

* define the new format, then load the device table on mount time make
  sure every thing is supported.

* Change I/O engine to now support Mirror IO, .i.e write same data
  to multiple devices, read from a random device to spread the
  read-load from multiple clients (TODO: stripe read)

Implementation notes:
 A few points introduced in previous patch should be mentioned here:

* Special care was made so absolutlly all operation that have any chance
  of failing are done before any osd-request is executed. This is to
  minimize the need for a data consistency recovery, to only real IO
  errors.

* Each IO state has a kref. It starts at 1, any osd-request executed
  will increment the kref, finally when all are executed the first ref
  is dropped. At IO-done, each request completion decrements the kref,
  the last one to return executes the internal _last_io() routine.
  _last_io() will call the registered io_state_done. On sync mode a
  caller does not supply a done method, indicating a synchronous
  request, the caller is put to sleep and a special io_state_done is
  registered that will awaken the caller. Though also in sync mode all
  operations are executed in parallel.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2009-12-10 09:59:23 +02:00

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/*
* Copyright (C) 2005, 2006
* Avishay Traeger (avishay@gmail.com)
* Copyright (C) 2008, 2009
* Boaz Harrosh <bharrosh@panasas.com>
*
* Copyrights for code taken from ext2:
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card (card@masi.ibp.fr)
* Laboratoire MASI - Institut Blaise Pascal
* Universite Pierre et Marie Curie (Paris VI)
* from
* linux/fs/minix/inode.c
* Copyright (C) 1991, 1992 Linus Torvalds
*
* This file is part of exofs.
*
* exofs is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation. Since it is based on ext2, and the only
* valid version of GPL for the Linux kernel is version 2, the only valid
* version of GPL for exofs is version 2.
*
* exofs is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with exofs; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __EXOFS_H__
#define __EXOFS_H__
#include <linux/fs.h>
#include <linux/time.h>
#include "common.h"
/* FIXME: Remove once pnfs hits mainline
* #include <linux/exportfs/pnfs_osd_xdr.h>
*/
#include "pnfs.h"
#define EXOFS_ERR(fmt, a...) printk(KERN_ERR "exofs: " fmt, ##a)
#ifdef CONFIG_EXOFS_DEBUG
#define EXOFS_DBGMSG(fmt, a...) \
printk(KERN_NOTICE "exofs @%s:%d: " fmt, __func__, __LINE__, ##a)
#else
#define EXOFS_DBGMSG(fmt, a...) \
do { if (0) printk(fmt, ##a); } while (0)
#endif
/* u64 has problems with printk this will cast it to unsigned long long */
#define _LLU(x) (unsigned long long)(x)
/*
* our extension to the in-memory superblock
*/
struct exofs_sb_info {
struct exofs_fscb s_fscb; /* Written often, pre-allocate*/
osd_id s_pid; /* partition ID of file system*/
int s_timeout; /* timeout for OSD operations */
uint64_t s_nextid; /* highest object ID used */
uint32_t s_numfiles; /* number of files on fs */
spinlock_t s_next_gen_lock; /* spinlock for gen # update */
u32 s_next_generation; /* next gen # to use */
atomic_t s_curr_pending; /* number of pending commands */
uint8_t s_cred[OSD_CAP_LEN]; /* credential for the fscb */
struct pnfs_osd_data_map data_map; /* Default raid to use */
unsigned s_numdevs; /* Num of devices in array */
struct osd_dev *s_ods[1]; /* Variable length, minimum 1 */
};
/*
* our extension to the in-memory inode
*/
struct exofs_i_info {
unsigned long i_flags; /* various atomic flags */
uint32_t i_data[EXOFS_IDATA];/*short symlink names and device #s*/
uint32_t i_dir_start_lookup; /* which page to start lookup */
wait_queue_head_t i_wq; /* wait queue for inode */
uint64_t i_commit_size; /* the object's written length */
uint8_t i_cred[OSD_CAP_LEN];/* all-powerful credential */
struct inode vfs_inode; /* normal in-memory inode */
};
static inline osd_id exofs_oi_objno(struct exofs_i_info *oi)
{
return oi->vfs_inode.i_ino + EXOFS_OBJ_OFF;
}
struct exofs_io_state;
typedef void (*exofs_io_done_fn)(struct exofs_io_state *or, void *private);
struct exofs_io_state {
struct kref kref;
void *private;
exofs_io_done_fn done;
struct exofs_sb_info *sbi;
struct osd_obj_id obj;
u8 *cred;
/* Global read/write IO*/
loff_t offset;
unsigned long length;
void *kern_buff;
struct bio *bio;
/* Attributes */
unsigned in_attr_len;
struct osd_attr *in_attr;
unsigned out_attr_len;
struct osd_attr *out_attr;
/* Variable array of size numdevs */
unsigned numdevs;
struct exofs_per_dev_state {
struct osd_request *or;
struct bio *bio;
} per_dev[];
};
static inline unsigned exofs_io_state_size(unsigned numdevs)
{
return sizeof(struct exofs_io_state) +
sizeof(struct exofs_per_dev_state) * numdevs;
}
/*
* our inode flags
*/
#define OBJ_2BCREATED 0 /* object will be created soon*/
#define OBJ_CREATED 1 /* object has been created on the osd*/
static inline int obj_2bcreated(struct exofs_i_info *oi)
{
return test_bit(OBJ_2BCREATED, &oi->i_flags);
}
static inline void set_obj_2bcreated(struct exofs_i_info *oi)
{
set_bit(OBJ_2BCREATED, &oi->i_flags);
}
static inline int obj_created(struct exofs_i_info *oi)
{
return test_bit(OBJ_CREATED, &oi->i_flags);
}
static inline void set_obj_created(struct exofs_i_info *oi)
{
set_bit(OBJ_CREATED, &oi->i_flags);
}
int __exofs_wait_obj_created(struct exofs_i_info *oi);
static inline int wait_obj_created(struct exofs_i_info *oi)
{
if (likely(obj_created(oi)))
return 0;
return __exofs_wait_obj_created(oi);
}
/*
* get to our inode from the vfs inode
*/
static inline struct exofs_i_info *exofs_i(struct inode *inode)
{
return container_of(inode, struct exofs_i_info, vfs_inode);
}
/*
* Maximum count of links to a file
*/
#define EXOFS_LINK_MAX 32000
/*************************
* function declarations *
*************************/
/* ios.c */
void exofs_make_credential(u8 cred_a[OSD_CAP_LEN],
const struct osd_obj_id *obj);
int exofs_read_kern(struct osd_dev *od, u8 *cred, struct osd_obj_id *obj,
u64 offset, void *p, unsigned length);
int exofs_get_io_state(struct exofs_sb_info *sbi, struct exofs_io_state** ios);
void exofs_put_io_state(struct exofs_io_state *ios);
int exofs_check_io(struct exofs_io_state *ios, u64 *resid);
int exofs_sbi_create(struct exofs_io_state *ios);
int exofs_sbi_remove(struct exofs_io_state *ios);
int exofs_sbi_write(struct exofs_io_state *ios);
int exofs_sbi_read(struct exofs_io_state *ios);
int extract_attr_from_ios(struct exofs_io_state *ios, struct osd_attr *attr);
int exofs_oi_truncate(struct exofs_i_info *oi, u64 new_len);
static inline int exofs_oi_write(struct exofs_i_info *oi,
struct exofs_io_state *ios)
{
ios->obj.id = exofs_oi_objno(oi);
ios->cred = oi->i_cred;
return exofs_sbi_write(ios);
}
static inline int exofs_oi_read(struct exofs_i_info *oi,
struct exofs_io_state *ios)
{
ios->obj.id = exofs_oi_objno(oi);
ios->cred = oi->i_cred;
return exofs_sbi_read(ios);
}
/* inode.c */
void exofs_truncate(struct inode *inode);
int exofs_setattr(struct dentry *, struct iattr *);
int exofs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
extern struct inode *exofs_iget(struct super_block *, unsigned long);
struct inode *exofs_new_inode(struct inode *, int);
extern int exofs_write_inode(struct inode *, int);
extern void exofs_delete_inode(struct inode *);
/* dir.c: */
int exofs_add_link(struct dentry *, struct inode *);
ino_t exofs_inode_by_name(struct inode *, struct dentry *);
int exofs_delete_entry(struct exofs_dir_entry *, struct page *);
int exofs_make_empty(struct inode *, struct inode *);
struct exofs_dir_entry *exofs_find_entry(struct inode *, struct dentry *,
struct page **);
int exofs_empty_dir(struct inode *);
struct exofs_dir_entry *exofs_dotdot(struct inode *, struct page **);
ino_t exofs_parent_ino(struct dentry *child);
int exofs_set_link(struct inode *, struct exofs_dir_entry *, struct page *,
struct inode *);
/* super.c */
int exofs_sync_fs(struct super_block *sb, int wait);
/*********************
* operation vectors *
*********************/
/* dir.c: */
extern const struct file_operations exofs_dir_operations;
/* file.c */
extern const struct inode_operations exofs_file_inode_operations;
extern const struct file_operations exofs_file_operations;
/* inode.c */
extern const struct address_space_operations exofs_aops;
extern const struct osd_attr g_attr_logical_length;
/* namei.c */
extern const struct inode_operations exofs_dir_inode_operations;
extern const struct inode_operations exofs_special_inode_operations;
/* symlink.c */
extern const struct inode_operations exofs_symlink_inode_operations;
extern const struct inode_operations exofs_fast_symlink_inode_operations;
#endif
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