Message-ID: <20081217222255.GA6317@joi>
Date:	Wed, 17 Dec 2008 23:23:01 +0100
From:	Marcin Slusarz <marcin.slusarz@...il.com>
To:	Boaz Harrosh <bharrosh@...asas.com>
Cc:	Avishay Traeger <avishay@...il.com>, Jeff Garzik <jeff@...zik.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Al Viro <viro@...IV.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	open-osd <osd-dev@...n-osd.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/9] exofs: super_operations and file_system_type

On Tue, Dec 16, 2008 at 05:31:30PM +0200, Boaz Harrosh wrote:
> 
> This patch ties all operation vectors into a file system superblock
> and registers the exofs file_system_type at module's load time.
> 
> * The file system control block (AKA on-disk superblock) resides in
>   an object with a special ID (defined in common.h).
>   Information included in the file system control block is used to
>   fill the in-memory superblock structure at mount time. This object
>   is created before the file system is used by mkexofs.c It contains
>   information such as:
> 	- The file system's magic number
> 	- The next inode number to be allocated
> 
> Signed-off-by: Boaz Harrosh <bharrosh@...asas.com>

Some minor comments below.

> ---
>  fs/exofs/Kbuild  |    2 +-
>  fs/exofs/exofs.h |   30 ++++
>  fs/exofs/inode.c |  195 +++++++++++++++++++++-
>  fs/exofs/super.c |  502 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 727 insertions(+), 2 deletions(-)
>  create mode 100644 fs/exofs/super.c
> 
> diff --git a/fs/exofs/Kbuild b/fs/exofs/Kbuild
> index 27c738c..e293cb9 100644
> --- a/fs/exofs/Kbuild
> +++ b/fs/exofs/Kbuild
> @@ -26,5 +26,5 @@ KBUILD_CPPFLAGS := -I$(OSD_INC) $(KBUILD_CPPFLAGS)
>  
>  endif
>  
> -exofs-objs := osd.o inode.o file.o symlink.o namei.o dir.o
> +exofs-objs := osd.o inode.o file.o symlink.o namei.o dir.o super.o
>  obj-$(CONFIG_EXOFS_FS) += exofs.o
> diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
> index 7330b59..75c608d 100644
> --- a/fs/exofs/exofs.h
> +++ b/fs/exofs/exofs.h
> @@ -52,6 +52,17 @@
>  #define _LLU(x) (unsigned long long)(x)
>  
>  /*
> + * struct to hold what we get from mount options
> + */
> +struct exofs_mountopt {
> +	const char *dev_name;
> +	uint64_t pid;
> +	int timeout;
> +	bool mkfs;
> +	int format; /*in Mbyte*/
> +};
> +
> +/*
>   * our extension to the in-memory superblock
>   */
>  struct exofs_sb_info {
> @@ -110,6 +121,14 @@ static inline struct exofs_i_info *EXOFS_I(struct inode *inode)
>  }
>  
>  /*
> + * ugly struct so that we can pass two arguments to update_inode's callback
> + */
> +struct updatei_args {
> +	struct exofs_sb_info	*sbi;
> +	struct exofs_fcb	*fcb;
> +};
> +
> +/*
>   * Maximum count of links to a file
>   */
>  #define EXOFS_LINK_MAX           32000
> @@ -188,12 +207,20 @@ void free_osd_req(struct osd_request *req);
>  /* inode.c               */
>  void exofs_truncate(struct inode *inode);
>  extern struct inode *exofs_iget(struct super_block *, unsigned long);
> +extern int exofs_write_inode(struct inode *, int);
> +extern void exofs_delete_inode(struct inode *);
>  struct inode *exofs_new_inode(struct inode *, int);
>  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);
>  
> +/* super.c:              */
> +#ifdef EXOFS_DEBUG
> +void exofs_dprint_internal(char *str, ...);
> +#endif
> +extern void exofs_write_super(struct super_block *);
> +
>  /* dir.c:                */
>  int exofs_add_link(struct dentry *, struct inode *);
>  ino_t exofs_inode_by_name(struct inode *, struct dentry *);
> @@ -223,6 +250,9 @@ extern struct address_space_operations exofs_aops;
>  extern struct inode_operations exofs_dir_inode_operations;
>  extern struct inode_operations exofs_special_inode_operations;
>  
> +/* super.c           */
> +extern struct super_operations exofs_sops;
> +
>  /* symlink.c         */
>  extern struct inode_operations exofs_symlink_inode_operations;
>  extern struct inode_operations exofs_fast_symlink_inode_operations;
> diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
> index 25a562e..e24690b 100644
> --- a/fs/exofs/inode.c
> +++ b/fs/exofs/inode.c
> @@ -37,6 +37,7 @@
>  #include "exofs.h"
>  
>  static int __readpage_filler(struct page *page, bool is_async_unlock);
> +static int exofs_update_inode(struct inode *inode, int do_sync);
>  
>  /*
>   * Test whether an inode is a fast symlink.
> @@ -49,6 +50,18 @@ static inline int exofs_inode_is_fast_symlink(struct inode *inode)
>  }
>  
>  /*
> + * Callback function from exofs_delete_inode() - don't have much cleaning up to
> + * do.
> + */
> +void delete_done(struct osd_request *req, void *p)

too generic name for non-static symbol (should it be static?)

> +{
> +	struct exofs_sb_info *sbi;
> +	free_osd_req(req);
> +	sbi = (struct exofs_sb_info *)p;
> +	atomic_dec(&sbi->s_curr_pending);
> +}
> +
> +/*
>   * get_block_t - Fill in a buffer_head
>   * An OSD takes care of block allocation so we just fake an allocation by
>   * putting in the inode's sector_t in the buffer_head.
> @@ -94,6 +107,62 @@ int exofs_write_begin_export(struct file *file, struct address_space *mapping,
>  }
>  
>  /*
> + * Called when the refcount of an inode reaches zero.  We remove the object
> + * from the OSD here.  We make sure the object was created before we try and
> + * delete it.
> + */
> +void exofs_delete_inode(struct inode *inode)
> +{
> +	struct exofs_i_info *oi = EXOFS_I(inode);
> +	struct osd_request *req = NULL;
> +	struct super_block *sb = inode->i_sb;
> +	struct exofs_sb_info *sbi = sb->s_fs_info;
> +	int ret;
> +
> +	truncate_inode_pages(&inode->i_data, 0);
> +
> +	if (is_bad_inode(inode))
> +		goto no_delete;
> +	mark_inode_dirty(inode);
> +	exofs_update_inode(inode, inode_needs_sync(inode));
> +
> +	inode->i_size = 0;
> +	if (inode->i_blocks)
> +		exofs_truncate(inode);
> +
> +	clear_inode(inode);
> +
> +	req = prepare_osd_remove(sbi->s_dev, sbi->s_pid,
> +				 inode->i_ino + EXOFS_OBJ_OFF);
> +	if (!req) {
> +		printk(KERN_ERR "ERROR: prepare_osd_remove failed\n");
> +		return;
> +	}
> +
> +	/* if we are deleting an obj that hasn't been created yet, wait */
> +	if (!ObjCreated(oi)) {
> +		if (!Obj2BCreated(oi))
> +			BUG();
> +		else
> +			wait_event(oi->i_wq, ObjCreated(oi));
> +	}
> +
> +	ret = exofs_async_op(req, delete_done, sbi, oi->i_cred);
> +	if (ret) {
> +		printk(KERN_ERR
> +		       "ERROR: @exofs_delete_inode exofs_async_op failed\n");
> +		free_osd_req(req);
> +		return;
> +	}
> +	atomic_inc(&sbi->s_curr_pending);
> +
> +	return;
> +
> +no_delete:
> +	clear_inode(inode);
> +}
> +
> +/*
>   * Callback function when writepage finishes.  Check for errors, unlock, clean
>   * up, etc.
>   */
> @@ -610,6 +679,131 @@ bad_inode:
>  }
>  
>  /*
> + * Callback function from exofs_update_inode().
> + */
> +void updatei_done(struct osd_request *req, void *p)
> +{
> +	struct updatei_args *args = (struct updatei_args *)p;
> +
> +	free_osd_req(req);
> +
> +	atomic_dec(&args->sbi->s_curr_pending);
> +
> +	kfree(args->fcb);
> +	kfree(args);
> +	args = NULL;

last line is a no-op

> +}
> +
> +/*
> + * Write the inode to the OSD.  Just fill up the struct, and set the attribute
> + * synchronously or asynchronously depending on the do_sync flag.
> + */
> +static int exofs_update_inode(struct inode *inode, int do_sync)
> +{
> +	struct exofs_i_info *oi = EXOFS_I(inode);
> +	struct super_block *sb = inode->i_sb;
> +	struct exofs_sb_info *sbi = sb->s_fs_info;
> +	struct osd_request *req = NULL;
> +	struct exofs_fcb *fcb = NULL;
> +	int ret;
> +	int n;
> +
> +	fcb = kmalloc(sizeof(struct exofs_fcb), GFP_KERNEL);
> +	if (!fcb) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	fcb->i_mode = cpu_to_be16(inode->i_mode);
> +	fcb->i_uid = cpu_to_be32(inode->i_uid);
> +	fcb->i_gid = cpu_to_be32(inode->i_gid);
> +	fcb->i_links_count = cpu_to_be16(inode->i_nlink);
> +	fcb->i_ctime = cpu_to_be32(inode->i_ctime.tv_sec);
> +	fcb->i_atime = cpu_to_be32(inode->i_atime.tv_sec);
> +	fcb->i_mtime = cpu_to_be32(inode->i_mtime.tv_sec);
> +	fcb->i_size = cpu_to_be64(oi->i_commit_size = i_size_read(inode));
> +	fcb->i_generation = cpu_to_be32(inode->i_generation);
> +
> +	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
> +		if (old_valid_dev(inode->i_rdev)) {
> +			fcb->i_data[0] = old_encode_dev(inode->i_rdev);
> +			fcb->i_data[1] = 0;
> +		} else {
> +			fcb->i_data[0] = 0;
> +			fcb->i_data[1] = new_encode_dev(inode->i_rdev);
> +			fcb->i_data[2] = 0;
> +		}
> +	} else
> +		for (n = 0; n < EXOFS_IDATA; n++)
> +			fcb->i_data[n] = oi->i_data[n];

memcpy?

> +
> +	req = prepare_osd_set_attr(sbi->s_dev, sbi->s_pid,
> +				 (uint64_t) (inode->i_ino + EXOFS_OBJ_OFF));
> +	if (!req) {
> +		printk(KERN_ERR "ERROR: prepare set_attr failed.\n");
> +		kfree(fcb);
> +		ret = -ENOMEM;
> +		goto out;
> +	}
> +
> +	prepare_set_attr_list_add_entry(req,
> +					OSD_PAGE_NUM_IBM_UOBJ_FS_DATA,
> +					OSD_ATTR_NUM_IBM_UOBJ_FS_DATA_INODE,
> +					EXOFS_INO_ATTR_SIZE,
> +					(unsigned char *)fcb);
> +
> +	if (!ObjCreated(oi)) {
> +		if (!Obj2BCreated(oi))
> +			BUG();
> +		else
> +			wait_event(oi->i_wq, ObjCreated(oi));
> +	}
> +
> +	if (do_sync) {
> +		ret = exofs_sync_op(req, sbi->s_timeout, oi->i_cred);
> +		free_osd_req(req);
> +		kfree(fcb);
> +	} else {
> +		struct updatei_args *args = NULL;
> +
> +		args = kmalloc(sizeof(struct updatei_args), GFP_KERNEL);
> +		if (!args) {
> +			kfree(fcb);
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +		args->sbi = sbi;
> +		args->fcb = fcb;
> +
> +		ret = exofs_async_op(req, updatei_done, args, oi->i_cred);
> +		if (ret) {
> +			free_osd_req(req);
> +			kfree(fcb);
> +			kfree(args);
> +			goto out;
> +		}
> +		atomic_inc(&sbi->s_curr_pending);
> +	}
> +out:
> +	return ret;
> +}

all kfree(fcb)'s can be moved after "out:"

> +
> +int exofs_write_inode(struct inode *inode, int wait)
> +{
> +	return exofs_update_inode(inode, wait);
> +}
> +
> +int exofs_sync_inode(struct inode *inode)
> +{
> +	struct writeback_control wbc = {
> +		.sync_mode = WB_SYNC_ALL,
> +		.nr_to_write = 0,	/* sys_fsync did this */
> +	};
> +
> +	return sync_inode(inode, &wbc);
> +}
> +
> +/*
>   * Set inode attributes - just call generic functions.
>   */
>  int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
> @@ -624,7 +818,6 @@ int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
>  	error = inode_setattr(inode, iattr);
>  	return error;
>  }
> -
>  /*
>   * Callback function from exofs_new_inode().  The important thing is that we
>   * set the ObjCreated flag so that other methods know that the object exists on
> diff --git a/fs/exofs/super.c b/fs/exofs/super.c
> new file mode 100644
> index 0000000..8ecf700
> --- /dev/null
> +++ b/fs/exofs/super.c
> @@ -0,0 +1,502 @@
> +/*
> + * Copyright (C) 2005, 2006
> + * Avishay Traeger (avishay@...il.com) (avishay@...ibm.com)
> + * Copyright (C) 2005, 2006
> + * International Business Machines
> + *
> + * Copyrights for code taken from ext2:
> + *     Copyright (C) 1992, 1993, 1994, 1995
> + *     Remy Card (card@...i.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
> + */
> +
> +#include <linux/string.h>
> +#include <linux/parser.h>
> +#include <linux/vfs.h>
> +#include <linux/random.h>
> +
> +#include "exofs.h"
> +
> +/******************************************************************************
> + * MOUNT OPTIONS
> + *****************************************************************************/
> +
> +/*
> + * exofs-specific mount-time options.
> + */
> +enum { Opt_lun, Opt_tid, Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
> +
> +/*
> + * Our mount-time options.  These should ideally be 64-bit unsigned, but the
> + * kernel's parsing functions do not currently support that.  32-bit should be
> + * sufficient for most applications now.
> + */
> +static match_table_t tokens = {
> +	{Opt_pid, "pid=%u"},
> +	{Opt_to, "to=%u"},
> +	{Opt_err, NULL}
> +};
> +
> +/*
> + * The main option parsing method.  Also makes sure that all of the mandatory
> + * mount options were set.
> + */
> +static int parse_options(char *options, struct exofs_mountopt *opts)
> +{
> +	char *p;
> +	substring_t args[MAX_OPT_ARGS];
> +	int option;
> +	int s_pid = 0;
> +
> +	EXOFS_DBGMSG("parse_options %s\n", options);
> +	/* defaults */
> +	memset(opts, 0, sizeof(*opts));
> +	opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
> +
> +	while ((p = strsep(&options, ",")) != NULL) {
> +		int token;
> +		if (!*p)
> +			continue;
> +
> +		token = match_token(p, tokens, args);
> +		switch (token) {
> +		case Opt_pid:
> +			if (match_int(&args[0], &option))
> +				return -EINVAL;
> +			if (option < 65536) {
> +				EXOFS_ERR("Partition ID must be >= 65536");
> +				return -EINVAL;
> +			}
> +			opts->pid = option;
> +			s_pid = 1;
> +			break;
> +		case Opt_to:
> +			if (match_int(&args[0], &option))
> +				return -EINVAL;
> +			if (option <= 0) {
> +				EXOFS_ERR("Timout must be > 0");
> +				return -EINVAL;
> +			}
> +			opts->timeout = option * HZ;
> +			break;
> +		}
> +	}
> +
> +	if (!s_pid) {
> +		EXOFS_ERR("Need to specify the following options:\n");
> +		EXOFS_ERR("    -o pid=pid_no_to_use\n");
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +/******************************************************************************
> + * INODE CACHE
> + *****************************************************************************/
> +
> +/*
> + * Our inode cache.  Isn't it pretty?
> + */
> +static struct kmem_cache *exofs_inode_cachep;
> +
> +/*
> + * Allocate an inode in the cache
> + */
> +static struct inode *exofs_alloc_inode(struct super_block *sb)
> +{
> +	struct exofs_i_info *oi;
> +
> +	oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
> +	if (!oi)
> +		return NULL;
> +
> +	oi->vfs_inode.i_version = 1;
> +	return &oi->vfs_inode;
> +}
> +
> +/*
> + * Remove an inode from the cache
> + */
> +static void exofs_destroy_inode(struct inode *inode)
> +{
> +	kmem_cache_free(exofs_inode_cachep, EXOFS_I(inode));
> +}
> +
> +/*
> + * Initialize the inode
> + */
> +static void exofs_init_once(void *foo)
> +{
> +	struct exofs_i_info *oi = foo;
> +
> +	inode_init_once(&oi->vfs_inode);
> +}
> +
> +/*
> + * Create and initialize the inode cache
> + */
> +static int init_inodecache(void)
> +{
> +	exofs_inode_cachep = kmem_cache_create("exofs_inode_cache",
> +					       sizeof(struct exofs_i_info),
> +					       0, SLAB_RECLAIM_ACCOUNT,
> +					       exofs_init_once);
> +	if (exofs_inode_cachep == NULL)
> +		return -ENOMEM;
> +	return 0;
> +}
> +
> +/*
> + * Destroy the inode cache
> + */
> +static void destroy_inodecache(void)
> +{
> +	kmem_cache_destroy(exofs_inode_cachep);
> +}
> +
> +/******************************************************************************
> + * SUPERBLOCK FUNCTIONS
> + *****************************************************************************/
> +
> +/*
> + * Write the superblock to the OSD
> + */
> +void exofs_write_super(struct super_block *sb)
> +{
> +	struct exofs_sb_info *sbi;
> +	struct exofs_fscb *fscb = NULL;
> +	struct osd_request *req = NULL;
> +
> +	fscb = kzalloc(sizeof(struct exofs_fscb), GFP_KERNEL);
> +	if (!fscb)
> +		return;
> +
> +	lock_kernel();
> +	sbi = sb->s_fs_info;
> +	fscb->s_nextid = sbi->s_nextid;
> +	fscb->s_magic = sb->s_magic;
> +	fscb->s_numfiles = sbi->s_numfiles;
> +	fscb->s_newfs = 0;
> +
> +	req = prepare_osd_write(sbi->s_dev, sbi->s_pid, EXOFS_SUPER_ID,
> +				sizeof(struct exofs_fscb), 0, 0,
> +				(unsigned char *)(fscb));
> +	if (!req) {
> +		EXOFS_ERR("ERROR: write super failed.\n");

unlock_kernel()
or just goto out

> +		kfree(fscb);
> +		return;
> +	}
> +
> +	exofs_sync_op(req, sbi->s_timeout, sbi->s_cred);
> +	free_osd_req(req);
> +	sb->s_dirt = 0;

out:

> +	unlock_kernel();
> +	kfree(fscb);
> +}
> +
> +/*
> + * This function is called when the vfs is freeing the superblock.  We just
> + * need to free our own part.
> + */
> +static void exofs_put_super(struct super_block *sb)
> +{
> +	int num_pend;
> +	struct exofs_sb_info *sbi = sb->s_fs_info;
> +
> +	/* make sure there are no pending commands */
> +	for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
> +	     num_pend = atomic_read(&sbi->s_curr_pending)) {
> +		wait_queue_head_t wq;
> +		init_waitqueue_head(&wq);
> +		wait_event_timeout(wq,
> +				  (atomic_read(&sbi->s_curr_pending) == 0),
> +				  msecs_to_jiffies(100));
> +	}
> +
> +	osduld_put_device(sbi->s_dev);
> +	kfree(sb->s_fs_info);
> +	sb->s_fs_info = NULL;
> +}
> +
> +/*
> + * Read the superblock from the OSD and fill in the fields
> + */
> +static int exofs_fill_super(struct super_block *sb, void *data, int silent)
> +{
> +	struct inode *root;
> +	struct exofs_mountopt *opts = data;
> +	struct exofs_sb_info *sbi = NULL;    /*extended info                  */
> +	struct exofs_fscb fscb;		     /*on-disk superblock info        */
> +	struct osd_request *req = NULL;
> +	int ret;
> +
> +	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
> +	if (!sbi)
> +		return -ENOMEM;
> +	sb->s_fs_info = sbi;
> +
> +	/* use mount options to fill superblock */
> +	sbi->s_dev = osduld_path_lookup(opts->dev_name);
> +	if (IS_ERR(sbi->s_dev)) {
> +		ret = PTR_ERR(sbi->s_dev);
> +		sbi->s_dev = NULL;
> +		goto free_sbi;
> +	}
> +
> +	sbi->s_pid = opts->pid;
> +	sbi->s_timeout = opts->timeout;
> +
> +	/* fill in some other data by hand */
> +	memset(sb->s_id, 0, sizeof(sb->s_id));

wasn't it zeroed by kzalloc?

> +	strcpy(sb->s_id, "exofs");
> +	sb->s_blocksize = EXOFS_BLKSIZE;
> +	sb->s_blocksize_bits = EXOFS_BLKSHIFT;
> +	atomic_set(&sbi->s_curr_pending, 0);
> +	sb->s_bdev = NULL;
> +	sb->s_dev = 0;
> +
> +	/* read data from on-disk superblock object */
> +	make_credential(sbi->s_cred, sbi->s_pid, EXOFS_SUPER_ID);
> +
> +	req = prepare_osd_read(sbi->s_dev, sbi->s_pid, EXOFS_SUPER_ID,
> +			       sizeof(struct exofs_fscb), 0, 0,
> +			       (unsigned char *)(&fscb));
> +	if (!req) {
> +		if (!silent)
> +			EXOFS_ERR("ERROR: could not prepare read request.\n");
> +		ret = -ENOMEM;
> +		goto free_sbi;
> +	}
> +
> +	ret = exofs_sync_op(req, sbi->s_timeout, sbi->s_cred);
> +	if (ret != 0) {
> +		if (!silent)
> +			EXOFS_ERR("ERROR: read super failed.\n");
> +		ret = -EIO;
> +		goto free_sbi;
> +	}
> +
> +	sb->s_magic = fscb.s_magic;
> +	sbi->s_nextid = fscb.s_nextid;
> +	sbi->s_numfiles = fscb.s_numfiles;
> +
> +	/* make sure what we read from the object store is correct */
> +	if (sb->s_magic != EXOFS_SUPER_MAGIC) {
> +		if (!silent)
> +			EXOFS_ERR("ERROR: Bad magic value\n");
> +		ret = -EINVAL;
> +		goto free_sbi;
> +	}
> +
> +	/* start generation numbers from a random point */
> +	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
> +	spin_lock_init(&sbi->s_next_gen_lock);
> +
> +	/* set up operation vectors */
> +	sb->s_op = &exofs_sops;
> +	root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
> +	if (IS_ERR(root)) {
> +		EXOFS_ERR("ERROR: exofs_iget faild\n");

typo (failed)

> +		ret = PTR_ERR(root);
> +		goto free_sbi;
> +	}
> +	sb->s_root = d_alloc_root(root);
> +	if (!sb->s_root) {
> +		iput(root);
> +		EXOFS_ERR("ERROR: get root inode failed\n");
> +		ret = -ENOMEM;
> +		goto free_sbi;
> +	}
> +
> +	if (!S_ISDIR(root->i_mode)) {
> +		dput(sb->s_root);
> +		sb->s_root = NULL;
> +		EXOFS_ERR("ERROR: corrupt root inode (mode = %hd)\n",
> +		       root->i_mode);
> +		ret = -EINVAL;
> +		goto free_sbi;
> +	}
> +
> +	ret = 0;
> +out:
> +	if (req)
> +		free_osd_req(req);
> +	return ret;
> +
> +free_sbi:
> +	osduld_put_device(sbi->s_dev); /* NULL safe */
> +	kfree(sbi);
> +	goto out;
> +}
> +
> +/*
> + * Set up the superblock (calls exofs_fill_super eventually)
> + */
> +static int exofs_get_sb(struct file_system_type *type,
> +			  int flags, const char *dev_name,
> +			  void *data, struct vfsmount *mnt)
> +{
> +	struct exofs_mountopt opts;
> +	int ret;
> +
> +	ret = parse_options((char *) data, &opts);
> +	if (ret)
> +		return ret;
> +
> +	opts.dev_name = dev_name;
> +	return get_sb_nodev(type, flags, &opts, exofs_fill_super, mnt);
> +}
> +
> +/*
> + * Return information about the file system state in the buffer.  This is used
> + * by the 'df' command, for example.
> + */
> +static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
> +{
> +	struct super_block *sb = dentry->d_sb;
> +	struct exofs_sb_info *sbi = sb->s_fs_info;
> +	uint8_t cred_a[OSD_CAP_LEN];
> +	struct osd_request *req = NULL;
> +	uint32_t page;
> +	uint32_t attr;
> +	uint16_t expected;
> +	uint64_t capacity;
> +	uint64_t used;
> +	uint8_t *data;
> +	int ret;
> +
> +	/* get used/capacity attributes */
> +	make_credential(cred_a, sbi->s_pid, 0);
> +
> +	req = prepare_osd_get_attr(sbi->s_dev, sbi->s_pid, 0);
> +	if (!req) {
> +		EXOFS_ERR("ERROR: prepare get_attr failed.\n");
> +		return -1;
> +	}
> +
> +	prepare_get_attr_list_add_entry(req,
> +			OSD_APAGE_PARTITION_QUOTAS,
> +			OSD_ATTR_PQ_CAPACITY_QUOTA,
> +			8);
> +
> +	prepare_get_attr_list_add_entry(req,
> +			OSD_APAGE_PARTITION_INFORMATION,
> +			OSD_ATTR_PI_USED_CAPACITY,
> +			8);
> +
> +	ret = exofs_sync_op(req, sbi->s_timeout, cred_a);
> +	if (ret)
> +		goto out;
> +
> +	page = OSD_APAGE_PARTITION_QUOTAS;
> +	attr = OSD_ATTR_PQ_CAPACITY_QUOTA;
> +	expected = 8;
> +	ret = extract_next_attr_from_req(req, &page, &attr, &expected, &data);
> +	if (ret) {
> +		EXOFS_ERR("ERROR: extract attr from req failed\n");
> +		goto out;
> +	}
> +	capacity = be64_to_cpu(*((uint64_t *)data));
> +
> +	page = OSD_APAGE_PARTITION_INFORMATION;
> +	attr = OSD_ATTR_PI_USED_CAPACITY;
> +	expected = 8;
> +	ret = extract_next_attr_from_req(req, &page, &attr, &expected, &data);
> +	if (ret) {
> +		EXOFS_ERR("ERROR: extract attr from req failed\n");
> +		goto out;
> +	}
> +	used = be64_to_cpu(*((uint64_t *)data));
> +
> +	/* fill in the stats buffer */
> +	buf->f_type = EXOFS_SUPER_MAGIC;
> +	buf->f_bsize = EXOFS_BLKSIZE;
> +	buf->f_blocks = (capacity >> EXOFS_BLKSHIFT);
> +	buf->f_bfree = ((capacity - used) >> EXOFS_BLKSHIFT);
> +	buf->f_bavail = buf->f_bfree;
> +	buf->f_files = sbi->s_numfiles;
> +	buf->f_ffree = EXOFS_MAX_ID - sbi->s_numfiles;
> +	buf->f_namelen = EXOFS_NAME_LEN;
> +out:
> +	free_osd_req(req);
> +
> +	return ret;
> +}
> +
> +struct super_operations exofs_sops = {
> +	.alloc_inode    = exofs_alloc_inode,
> +	.destroy_inode  = exofs_destroy_inode,
> +	.write_inode    = exofs_write_inode,
> +	.delete_inode   = exofs_delete_inode,
> +	.put_super      = exofs_put_super,
> +	.write_super    = exofs_write_super,
> +	.statfs         = exofs_statfs,
> +};
> +
> +/******************************************************************************
> + * INSMOD/RMMOD
> + *****************************************************************************/
> +
> +/*
> + * struct that describes this file system
> + */
> +static struct file_system_type exofs_type = {
> +	.owner          = THIS_MODULE,
> +	.name           = "exofs",
> +	.get_sb         = exofs_get_sb,
> +	.kill_sb        = generic_shutdown_super,
> +};
> +
> +static int __init init_exofs(void)
> +{
> +	int err;
> +
> +	err = init_inodecache();
> +	if (err)
> +		goto out;
> +
> +	err = register_filesystem(&exofs_type);
> +	if (err)
> +		goto out_d;
> +
> +	return 0;
> +out_d:
> +	destroy_inodecache();
> +out:
> +	return err;
> +}
> +
> +static void __exit exit_exofs(void)
> +{
> +	unregister_filesystem(&exofs_type);
> +	destroy_inodecache();
> +}
> +
> +MODULE_AUTHOR("Avishay Traeger <avishay@...il.com>");
> +MODULE_DESCRIPTION("exofs");
> +MODULE_LICENSE("GPL");
> +
> +module_init(init_exofs)
> +module_exit(exit_exofs)
> -- 
> 1.6.0.1
--
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