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linux/fs/exofs/super.c
Linus Torvalds bf25db3654 Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 
* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  exofs: Fix groups code when num_devices is not divisible by group_width
  exofs: Remove useless optimization
  exofs: exofs_file_fsync and exofs_file_flush correctness
  exofs: Remove superfluous dependency on buffer_head and writeback
2010-08-11 09:19:43 -07:00

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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
*/
#include <linux/string.h>
#include <linux/parser.h>
#include <linux/vfs.h>
#include <linux/random.h>
#include <linux/exportfs.h>
#include <linux/slab.h>
#include "exofs.h"
/******************************************************************************
* MOUNT OPTIONS
*****************************************************************************/
/*
* struct to hold what we get from mount options
*/
struct exofs_mountopt {
const char *dev_name;
uint64_t pid;
int timeout;
};
/*
* exofs-specific mount-time options.
*/
enum { 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;
bool s_pid = false;
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;
char str[32];
if (!*p)
continue;
token = match_token(p, tokens, args);
switch (token) {
case Opt_pid:
if (0 == match_strlcpy(str, &args[0], sizeof(str)))
return -EINVAL;
opts->pid = simple_strtoull(str, NULL, 0);
if (opts->pid < EXOFS_MIN_PID) {
EXOFS_ERR("Partition ID must be >= %u",
EXOFS_MIN_PID);
return -EINVAL;
}
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 | SLAB_MEM_SPREAD,
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
*****************************************************************************/
static const struct super_operations exofs_sops;
static const struct export_operations exofs_export_ops;
/*
* Write the superblock to the OSD
*/
int exofs_sync_fs(struct super_block *sb, int wait)
{
struct exofs_sb_info *sbi;
struct exofs_fscb *fscb;
struct exofs_io_state *ios;
int ret = -ENOMEM;
lock_super(sb);
sbi = sb->s_fs_info;
fscb = &sbi->s_fscb;
ret = exofs_get_io_state(&sbi->layout, &ios);
if (ret)
goto out;
/* Note: We only write the changing part of the fscb. .i.e upto the
* the fscb->s_dev_table_oid member. There is no read-modify-write
* here.
*/
ios->length = offsetof(struct exofs_fscb, s_dev_table_oid);
memset(fscb, 0, ios->length);
fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
fscb->s_magic = cpu_to_le16(sb->s_magic);
fscb->s_newfs = 0;
fscb->s_version = EXOFS_FSCB_VER;
ios->obj.id = EXOFS_SUPER_ID;
ios->offset = 0;
ios->kern_buff = fscb;
ios->cred = sbi->s_cred;
ret = exofs_sbi_write(ios);
if (unlikely(ret)) {
EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
goto out;
}
sb->s_dirt = 0;
out:
EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
exofs_put_io_state(ios);
unlock_super(sb);
return ret;
}
static void exofs_write_super(struct super_block *sb)
{
if (!(sb->s_flags & MS_RDONLY))
exofs_sync_fs(sb, 1);
else
sb->s_dirt = 0;
}
static void _exofs_print_device(const char *msg, const char *dev_path,
struct osd_dev *od, u64 pid)
{
const struct osd_dev_info *odi = osduld_device_info(od);
printk(KERN_NOTICE "exofs: %s %s osd_name-%s pid-0x%llx\n",
msg, dev_path ?: "", odi->osdname, _LLU(pid));
}
void exofs_free_sbi(struct exofs_sb_info *sbi)
{
while (sbi->layout.s_numdevs) {
int i = --sbi->layout.s_numdevs;
struct osd_dev *od = sbi->layout.s_ods[i];
if (od) {
sbi->layout.s_ods[i] = NULL;
osduld_put_device(od);
}
}
kfree(sbi);
}
/*
* 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;
if (sb->s_dirt)
exofs_write_super(sb);
/* 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));
}
_exofs_print_device("Unmounting", NULL, sbi->layout.s_ods[0],
sbi->layout.s_pid);
bdi_destroy(&sbi->bdi);
exofs_free_sbi(sbi);
sb->s_fs_info = NULL;
}
static int _read_and_match_data_map(struct exofs_sb_info *sbi, unsigned numdevs,
struct exofs_device_table *dt)
{
u64 stripe_length;
sbi->data_map.odm_num_comps =
le32_to_cpu(dt->dt_data_map.cb_num_comps);
sbi->data_map.odm_stripe_unit =
le64_to_cpu(dt->dt_data_map.cb_stripe_unit);
sbi->data_map.odm_group_width =
le32_to_cpu(dt->dt_data_map.cb_group_width);
sbi->data_map.odm_group_depth =
le32_to_cpu(dt->dt_data_map.cb_group_depth);
sbi->data_map.odm_mirror_cnt =
le32_to_cpu(dt->dt_data_map.cb_mirror_cnt);
sbi->data_map.odm_raid_algorithm =
le32_to_cpu(dt->dt_data_map.cb_raid_algorithm);
/* FIXME: Only raid0 for now. if not so, do not mount */
if (sbi->data_map.odm_num_comps != numdevs) {
EXOFS_ERR("odm_num_comps(%u) != numdevs(%u)\n",
sbi->data_map.odm_num_comps, numdevs);
return -EINVAL;
}
if (sbi->data_map.odm_raid_algorithm != PNFS_OSD_RAID_0) {
EXOFS_ERR("Only RAID_0 for now\n");
return -EINVAL;
}
if (0 != (numdevs % (sbi->data_map.odm_mirror_cnt + 1))) {
EXOFS_ERR("Data Map wrong, numdevs=%d mirrors=%d\n",
numdevs, sbi->data_map.odm_mirror_cnt);
return -EINVAL;
}
if (0 != (sbi->data_map.odm_stripe_unit & ~PAGE_MASK)) {
EXOFS_ERR("Stripe Unit(0x%llx)"
" must be Multples of PAGE_SIZE(0x%lx)\n",
_LLU(sbi->data_map.odm_stripe_unit), PAGE_SIZE);
return -EINVAL;
}
sbi->layout.stripe_unit = sbi->data_map.odm_stripe_unit;
sbi->layout.mirrors_p1 = sbi->data_map.odm_mirror_cnt + 1;
if (sbi->data_map.odm_group_width) {
sbi->layout.group_width = sbi->data_map.odm_group_width;
sbi->layout.group_depth = sbi->data_map.odm_group_depth;
if (!sbi->layout.group_depth) {
EXOFS_ERR("group_depth == 0 && group_width != 0\n");
return -EINVAL;
}
sbi->layout.group_count = sbi->data_map.odm_num_comps /
sbi->layout.mirrors_p1 /
sbi->data_map.odm_group_width;
} else {
if (sbi->data_map.odm_group_depth) {
printk(KERN_NOTICE "Warning: group_depth ignored "
"group_width == 0 && group_depth == %d\n",
sbi->data_map.odm_group_depth);
sbi->data_map.odm_group_depth = 0;
}
sbi->layout.group_width = sbi->data_map.odm_num_comps /
sbi->layout.mirrors_p1;
sbi->layout.group_depth = -1;
sbi->layout.group_count = 1;
}
stripe_length = (u64)sbi->layout.group_width * sbi->layout.stripe_unit;
if (stripe_length >= (1ULL << 32)) {
EXOFS_ERR("Total Stripe length(0x%llx)"
" >= 32bit is not supported\n", _LLU(stripe_length));
return -EINVAL;
}
return 0;
}
/* @odi is valid only as long as @fscb_dev is valid */
static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
struct osd_dev_info *odi)
{
odi->systemid_len = le32_to_cpu(dt_dev->systemid_len);
memcpy(odi->systemid, dt_dev->systemid, odi->systemid_len);
odi->osdname_len = le32_to_cpu(dt_dev->osdname_len);
odi->osdname = dt_dev->osdname;
/* FIXME support long names. Will need a _put function */
if (dt_dev->long_name_offset)
return -EINVAL;
/* Make sure osdname is printable!
* mkexofs should give us space for a null-terminator else the
* device-table is invalid.
*/
if (unlikely(odi->osdname_len >= sizeof(dt_dev->osdname)))
odi->osdname_len = sizeof(dt_dev->osdname) - 1;
dt_dev->osdname[odi->osdname_len] = 0;
/* If it's all zeros something is bad we read past end-of-obj */
return !(odi->systemid_len || odi->osdname_len);
}
static int exofs_read_lookup_dev_table(struct exofs_sb_info **psbi,
unsigned table_count)
{
struct exofs_sb_info *sbi = *psbi;
struct osd_dev *fscb_od;
struct osd_obj_id obj = {.partition = sbi->layout.s_pid,
.id = EXOFS_DEVTABLE_ID};
struct exofs_device_table *dt;
unsigned table_bytes = table_count * sizeof(dt->dt_dev_table[0]) +
sizeof(*dt);
unsigned numdevs, i;
int ret;
dt = kmalloc(table_bytes, GFP_KERNEL);
if (unlikely(!dt)) {
EXOFS_ERR("ERROR: allocating %x bytes for device table\n",
table_bytes);
return -ENOMEM;
}
fscb_od = sbi->layout.s_ods[0];
sbi->layout.s_ods[0] = NULL;
sbi->layout.s_numdevs = 0;
ret = exofs_read_kern(fscb_od, sbi->s_cred, &obj, 0, dt, table_bytes);
if (unlikely(ret)) {
EXOFS_ERR("ERROR: reading device table\n");
goto out;
}
numdevs = le64_to_cpu(dt->dt_num_devices);
if (unlikely(!numdevs)) {
ret = -EINVAL;
goto out;
}
WARN_ON(table_count != numdevs);
ret = _read_and_match_data_map(sbi, numdevs, dt);
if (unlikely(ret))
goto out;
if (likely(numdevs > 1)) {
unsigned size = numdevs * sizeof(sbi->layout.s_ods[0]);
sbi = krealloc(sbi, sizeof(*sbi) + size, GFP_KERNEL);
if (unlikely(!sbi)) {
ret = -ENOMEM;
goto out;
}
memset(&sbi->layout.s_ods[1], 0,
size - sizeof(sbi->layout.s_ods[0]));
*psbi = sbi;
}
for (i = 0; i < numdevs; i++) {
struct exofs_fscb fscb;
struct osd_dev_info odi;
struct osd_dev *od;
if (exofs_devs_2_odi(&dt->dt_dev_table[i], &odi)) {
EXOFS_ERR("ERROR: Read all-zeros device entry\n");
ret = -EINVAL;
goto out;
}
printk(KERN_NOTICE "Add device[%d]: osd_name-%s\n",
i, odi.osdname);
/* On all devices the device table is identical. The user can
* specify any one of the participating devices on the command
* line. We always keep them in device-table order.
*/
if (fscb_od && osduld_device_same(fscb_od, &odi)) {
sbi->layout.s_ods[i] = fscb_od;
++sbi->layout.s_numdevs;
fscb_od = NULL;
continue;
}
od = osduld_info_lookup(&odi);
if (unlikely(IS_ERR(od))) {
ret = PTR_ERR(od);
EXOFS_ERR("ERROR: device requested is not found "
"osd_name-%s =>%d\n", odi.osdname, ret);
goto out;
}
sbi->layout.s_ods[i] = od;
++sbi->layout.s_numdevs;
/* Read the fscb of the other devices to make sure the FS
* partition is there.
*/
ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb,
sizeof(fscb));
if (unlikely(ret)) {
EXOFS_ERR("ERROR: Malformed participating device "
"error reading fscb osd_name-%s\n",
odi.osdname);
goto out;
}
/* TODO: verify other information is correct and FS-uuid
* matches. Benny what did you say about device table
* generation and old devices?
*/
}
out:
kfree(dt);
if (unlikely(!ret && fscb_od)) {
EXOFS_ERR(
"ERROR: Bad device-table container device not present\n");
osduld_put_device(fscb_od);
ret = -EINVAL;
}
return ret;
}
/*
* 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; /*extended info */
struct osd_dev *od; /* Master device */
struct exofs_fscb fscb; /*on-disk superblock info */
struct osd_obj_id obj;
unsigned table_count;
int ret;
sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
if (!sbi)
return -ENOMEM;
ret = bdi_setup_and_register(&sbi->bdi, "exofs", BDI_CAP_MAP_COPY);
if (ret)
goto free_bdi;
/* use mount options to fill superblock */
od = osduld_path_lookup(opts->dev_name);
if (IS_ERR(od)) {
ret = PTR_ERR(od);
goto free_sbi;
}
/* Default layout in case we do not have a device-table */
sbi->layout.stripe_unit = PAGE_SIZE;
sbi->layout.mirrors_p1 = 1;
sbi->layout.group_width = 1;
sbi->layout.group_depth = -1;
sbi->layout.group_count = 1;
sbi->layout.s_ods[0] = od;
sbi->layout.s_numdevs = 1;
sbi->layout.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));
strcpy(sb->s_id, "exofs");
sb->s_blocksize = EXOFS_BLKSIZE;
sb->s_blocksize_bits = EXOFS_BLKSHIFT;
sb->s_maxbytes = MAX_LFS_FILESIZE;
atomic_set(&sbi->s_curr_pending, 0);
sb->s_bdev = NULL;
sb->s_dev = 0;
obj.partition = sbi->layout.s_pid;
obj.id = EXOFS_SUPER_ID;
exofs_make_credential(sbi->s_cred, &obj);
ret = exofs_read_kern(od, sbi->s_cred, &obj, 0, &fscb, sizeof(fscb));
if (unlikely(ret))
goto free_sbi;
sb->s_magic = le16_to_cpu(fscb.s_magic);
sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
sbi->s_numfiles = le32_to_cpu(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;
}
if (le32_to_cpu(fscb.s_version) != EXOFS_FSCB_VER) {
EXOFS_ERR("ERROR: Bad FSCB version expected-%d got-%d\n",
EXOFS_FSCB_VER, le32_to_cpu(fscb.s_version));
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);
table_count = le64_to_cpu(fscb.s_dev_table_count);
if (table_count) {
ret = exofs_read_lookup_dev_table(&sbi, table_count);
if (unlikely(ret))
goto free_sbi;
}
/* set up operation vectors */
sb->s_bdi = &sbi->bdi;
sb->s_fs_info = sbi;
sb->s_op = &exofs_sops;
sb->s_export_op = &exofs_export_ops;
root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
if (IS_ERR(root)) {
EXOFS_ERR("ERROR: exofs_iget failed\n");
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;
}
_exofs_print_device("Mounting", opts->dev_name, sbi->layout.s_ods[0],
sbi->layout.s_pid);
return 0;
free_sbi:
bdi_destroy(&sbi->bdi);
free_bdi:
EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
opts->dev_name, sbi->layout.s_pid, ret);
exofs_free_sbi(sbi);
return ret;
}
/*
* 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(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;
struct exofs_io_state *ios;
struct osd_attr attrs[] = {
ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
ATTR_DEF(OSD_APAGE_PARTITION_INFORMATION,
OSD_ATTR_PI_USED_CAPACITY, sizeof(__be64)),
};
uint64_t capacity = ULLONG_MAX;
uint64_t used = ULLONG_MAX;
uint8_t cred_a[OSD_CAP_LEN];
int ret;
ret = exofs_get_io_state(&sbi->layout, &ios);
if (ret) {
EXOFS_DBGMSG("exofs_get_io_state failed.\n");
return ret;
}
exofs_make_credential(cred_a, &ios->obj);
ios->cred = sbi->s_cred;
ios->in_attr = attrs;
ios->in_attr_len = ARRAY_SIZE(attrs);
ret = exofs_sbi_read(ios);
if (unlikely(ret))
goto out;
ret = extract_attr_from_ios(ios, &attrs[0]);
if (likely(!ret)) {
capacity = get_unaligned_be64(attrs[0].val_ptr);
if (unlikely(!capacity))
capacity = ULLONG_MAX;
} else
EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
ret = extract_attr_from_ios(ios, &attrs[1]);
if (likely(!ret))
used = get_unaligned_be64(attrs[1].val_ptr);
else
EXOFS_DBGMSG("exofs_statfs: get used-space failed.\n");
/* fill in the stats buffer */
buf->f_type = EXOFS_SUPER_MAGIC;
buf->f_bsize = EXOFS_BLKSIZE;
buf->f_blocks = capacity >> 9;
buf->f_bfree = (capacity - used) >> 9;
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:
exofs_put_io_state(ios);
return ret;
}
static const struct super_operations exofs_sops = {
.alloc_inode = exofs_alloc_inode,
.destroy_inode = exofs_destroy_inode,
.write_inode = exofs_write_inode,
.evict_inode = exofs_evict_inode,
.put_super = exofs_put_super,
.write_super = exofs_write_super,
.sync_fs = exofs_sync_fs,
.statfs = exofs_statfs,
};
/******************************************************************************
* EXPORT OPERATIONS
*****************************************************************************/
struct dentry *exofs_get_parent(struct dentry *child)
{
unsigned long ino = exofs_parent_ino(child);
if (!ino)
return NULL;
return d_obtain_alias(exofs_iget(child->d_inode->i_sb, ino));
}
static struct inode *exofs_nfs_get_inode(struct super_block *sb,
u64 ino, u32 generation)
{
struct inode *inode;
inode = exofs_iget(sb, ino);
if (IS_ERR(inode))
return ERR_CAST(inode);
if (generation && inode->i_generation != generation) {
/* we didn't find the right inode.. */
iput(inode);
return ERR_PTR(-ESTALE);
}
return inode;
}
static struct dentry *exofs_fh_to_dentry(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
exofs_nfs_get_inode);
}
static struct dentry *exofs_fh_to_parent(struct super_block *sb,
struct fid *fid, int fh_len, int fh_type)
{
return generic_fh_to_parent(sb, fid, fh_len, fh_type,
exofs_nfs_get_inode);
}
static const struct export_operations exofs_export_ops = {
.fh_to_dentry = exofs_fh_to_dentry,
.fh_to_parent = exofs_fh_to_parent,
.get_parent = exofs_get_parent,
};
/******************************************************************************
* 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@gmail.com>");
MODULE_DESCRIPTION("exofs");
MODULE_LICENSE("GPL");
module_init(init_exofs)
module_exit(exit_exofs)
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