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    Subject[RFC v2 08/83] NOVA superblock operations.
    Date
    From: Andiry Xu <jix024@cs.ucsd.edu>

    This is the entry point for NOVA filesystem mount and umount.
    NOVA works on DAX devices. During initialization it gets the
    device information, such as physical/virtual addresses and device size.
    It does not access the DAX device during runtime.

    During initialization NOVA also initializes the root inode.
    The root inode is a reserved inode and resides on the fixed location.

    The way to mount and initialize a NOVA instance is:

    mount -t NOVA -o init /dev/pmem0 /mnt/NOVA

    This creates a NOVA instance on /dev/pmem0 and mount on /mnt/NOVA.
    Currently it cannot do anything except mount and umount.

    Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
    ---
    fs/nova/super.c | 630 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    1 file changed, 630 insertions(+)
    create mode 100644 fs/nova/super.c

    diff --git a/fs/nova/super.c b/fs/nova/super.c
    new file mode 100644
    index 0000000..552fe5d
    --- /dev/null
    +++ b/fs/nova/super.c
    @@ -0,0 +1,630 @@
    +/*
    + * BRIEF DESCRIPTION
    + *
    + * Super block operations.
    + *
    + * Copyright 2015-2016 Regents of the University of California,
    + * UCSD Non-Volatile Systems Lab, Andiry Xu <jix024@cs.ucsd.edu>
    + * Copyright 2012-2013 Intel Corporation
    + * Copyright 2009-2011 Marco Stornelli <marco.stornelli@gmail.com>
    + * Copyright 2003 Sony Corporation
    + * Copyright 2003 Matsushita Electric Industrial Co., Ltd.
    + * 2003-2004 (c) MontaVista Software, Inc. , Steve Longerbeam
    + *
    + * This program is free software; you can redistribute it and/or modify it
    + *
    + * This file is licensed under the terms of the GNU General Public
    + * License version 2. This program is licensed "as is" without any
    + * warranty of any kind, whether express or implied.
    + */
    +
    +#include <linux/module.h>
    +#include <linux/string.h>
    +#include <linux/slab.h>
    +#include <linux/init.h>
    +#include <linux/parser.h>
    +#include <linux/vfs.h>
    +#include <linux/uaccess.h>
    +#include <linux/io.h>
    +#include <linux/seq_file.h>
    +#include <linux/mount.h>
    +#include <linux/mm.h>
    +#include <linux/ctype.h>
    +#include <linux/bitops.h>
    +#include <linux/magic.h>
    +#include <linux/exportfs.h>
    +#include <linux/random.h>
    +#include <linux/cred.h>
    +#include <linux/list.h>
    +#include <linux/dax.h>
    +#include "nova.h"
    +#include "super.h"
    +
    +int support_clwb;
    +
    +module_param(nova_dbgmask, int, 0444);
    +MODULE_PARM_DESC(nova_dbgmask, "Control debugging output");
    +
    +static struct super_operations nova_sops;
    +
    +static struct kmem_cache *nova_inode_cachep;
    +
    +
    +/* FIXME: should the following variable be one per NOVA instance? */
    +unsigned int nova_dbgmask;
    +
    +void nova_error_mng(struct super_block *sb, const char *fmt, ...)
    +{
    + va_list args;
    +
    + printk(KERN_CRIT "nova error: ");
    + va_start(args, fmt);
    + vprintk(fmt, args);
    + va_end(args);
    +
    + if (test_opt(sb, ERRORS_PANIC))
    + panic("nova: panic from previous error\n");
    + if (test_opt(sb, ERRORS_RO)) {
    + printk(KERN_CRIT "nova err: remounting filesystem read-only");
    + sb->s_flags |= MS_RDONLY;
    + }
    +}
    +
    +static void nova_set_blocksize(struct super_block *sb, unsigned long size)
    +{
    + int bits;
    +
    + /*
    + * We've already validated the user input and the value here must be
    + * between NOVA_MAX_BLOCK_SIZE and NOVA_MIN_BLOCK_SIZE
    + * and it must be a power of 2.
    + */
    + bits = fls(size) - 1;
    + sb->s_blocksize_bits = bits;
    + sb->s_blocksize = (1 << bits);
    +}
    +
    +static int nova_get_nvmm_info(struct super_block *sb,
    + struct nova_sb_info *sbi)
    +{
    + void *virt_addr = NULL;
    + pfn_t __pfn_t;
    + long size;
    + struct dax_device *dax_dev;
    + int ret;
    +
    + ret = bdev_dax_supported(sb, PAGE_SIZE);
    + nova_dbg_verbose("%s: dax_supported = %d; bdev->super=0x%p",
    + __func__, ret, sb->s_bdev->bd_super);
    + if (ret) {
    + nova_err(sb, "device does not support DAX\n");
    + return ret;
    + }
    +
    + sbi->s_bdev = sb->s_bdev;
    +
    + dax_dev = fs_dax_get_by_host(sb->s_bdev->bd_disk->disk_name);
    + if (!dax_dev) {
    + nova_err(sb, "Couldn't retrieve DAX device.\n");
    + return -EINVAL;
    + }
    + sbi->s_dax_dev = dax_dev;
    +
    + size = dax_direct_access(sbi->s_dax_dev, 0, LONG_MAX/PAGE_SIZE,
    + &virt_addr, &__pfn_t) * PAGE_SIZE;
    + if (size <= 0) {
    + nova_err(sb, "direct_access failed\n");
    + return -EINVAL;
    + }
    +
    + sbi->virt_addr = virt_addr;
    +
    + if (!sbi->virt_addr) {
    + nova_err(sb, "ioremap of the nova image failed(1)\n");
    + return -EINVAL;
    + }
    +
    + sbi->phys_addr = pfn_t_to_pfn(__pfn_t) << PAGE_SHIFT;
    + sbi->initsize = size;
    + sbi->replica_reserved_inodes_addr = virt_addr + size -
    + (sbi->tail_reserved_blocks << PAGE_SHIFT);
    + sbi->replica_sb_addr = virt_addr + size - PAGE_SIZE;
    +
    + nova_dbg("%s: dev %s, phys_addr 0x%llx, virt_addr %p, size %ld\n",
    + __func__, sbi->s_bdev->bd_disk->disk_name,
    + sbi->phys_addr, sbi->virt_addr, sbi->initsize);
    +
    + return 0;
    +}
    +
    +static loff_t nova_max_size(int bits)
    +{
    + loff_t res;
    +
    + res = (1ULL << 63) - 1;
    +
    + if (res > MAX_LFS_FILESIZE)
    + res = MAX_LFS_FILESIZE;
    +
    + nova_dbg_verbose("max file size %llu bytes\n", res);
    + return res;
    +}
    +
    +enum {
    + Opt_bpi, Opt_init, Opt_mode, Opt_uid,
    + Opt_gid, Opt_dax,
    + Opt_err_cont, Opt_err_panic, Opt_err_ro,
    + Opt_dbgmask, Opt_err
    +};
    +
    +static const match_table_t tokens = {
    + { Opt_bpi, "bpi=%u" },
    + { Opt_init, "init" },
    + { Opt_mode, "mode=%o" },
    + { Opt_uid, "uid=%u" },
    + { Opt_gid, "gid=%u" },
    + { Opt_dax, "dax" },
    + { Opt_err_cont, "errors=continue" },
    + { Opt_err_panic, "errors=panic" },
    + { Opt_err_ro, "errors=remount-ro" },
    + { Opt_dbgmask, "dbgmask=%u" },
    + { Opt_err, NULL },
    +};
    +
    +static int nova_parse_options(char *options, struct nova_sb_info *sbi,
    + bool remount)
    +{
    + char *p;
    + substring_t args[MAX_OPT_ARGS];
    + int option;
    + kuid_t uid;
    +
    + if (!options)
    + return 0;
    +
    + while ((p = strsep(&options, ",")) != NULL) {
    + int token;
    +
    + if (!*p)
    + continue;
    +
    + token = match_token(p, tokens, args);
    + switch (token) {
    + case Opt_bpi:
    + if (match_int(&args[0], &option))
    + goto bad_val;
    + if (remount && sbi->bpi)
    + goto bad_opt;
    + sbi->bpi = option;
    + break;
    + case Opt_uid:
    + if (match_int(&args[0], &option))
    + goto bad_val;
    + uid = make_kuid(current_user_ns(), option);
    + if (remount && !uid_eq(sbi->uid, uid))
    + goto bad_opt;
    + sbi->uid = uid;
    + break;
    + case Opt_gid:
    + if (match_int(&args[0], &option))
    + goto bad_val;
    + sbi->gid = make_kgid(current_user_ns(), option);
    + break;
    + case Opt_mode:
    + if (match_octal(&args[0], &option))
    + goto bad_val;
    + sbi->mode = option & 01777U;
    + break;
    + case Opt_init:
    + if (remount)
    + goto bad_opt;
    + set_opt(sbi->s_mount_opt, FORMAT);
    + break;
    + case Opt_err_panic:
    + clear_opt(sbi->s_mount_opt, ERRORS_CONT);
    + clear_opt(sbi->s_mount_opt, ERRORS_RO);
    + set_opt(sbi->s_mount_opt, ERRORS_PANIC);
    + break;
    + case Opt_err_ro:
    + clear_opt(sbi->s_mount_opt, ERRORS_CONT);
    + clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
    + set_opt(sbi->s_mount_opt, ERRORS_RO);
    + break;
    + case Opt_err_cont:
    + clear_opt(sbi->s_mount_opt, ERRORS_RO);
    + clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
    + set_opt(sbi->s_mount_opt, ERRORS_CONT);
    + break;
    + case Opt_dax:
    + set_opt(sbi->s_mount_opt, DAX);
    + break;
    + case Opt_dbgmask:
    + if (match_int(&args[0], &option))
    + goto bad_val;
    + nova_dbgmask = option;
    + break;
    + default: {
    + goto bad_opt;
    + }
    + }
    + }
    +
    + return 0;
    +
    +bad_val:
    + nova_info("Bad value '%s' for mount option '%s'\n", args[0].from,
    + p);
    + return -EINVAL;
    +bad_opt:
    + nova_info("Bad mount option: \"%s\"\n", p);
    + return -EINVAL;
    +}
    +
    +
    +/* Make sure we have enough space */
    +static bool nova_check_size(struct super_block *sb, unsigned long size)
    +{
    + unsigned long minimum_size;
    +
    + /* space required for super block and root directory.*/
    + minimum_size = (HEAD_RESERVED_BLOCKS + TAIL_RESERVED_BLOCKS + 1)
    + << sb->s_blocksize_bits;
    +
    + if (size < minimum_size)
    + return false;
    +
    + return true;
    +}
    +
    +static inline void nova_sync_super(struct super_block *sb)
    +{
    + struct nova_sb_info *sbi = NOVA_SB(sb);
    + struct nova_super_block *super = nova_get_super(sb);
    + struct nova_super_block *super_redund;
    +
    + super_redund = nova_get_redund_super(sb);
    +
    + memcpy_to_pmem_nocache((void *)super, (void *)sbi->nova_sb,
    + sizeof(struct nova_super_block));
    + PERSISTENT_BARRIER();
    +
    + memcpy_to_pmem_nocache((void *)super_redund, (void *)sbi->nova_sb,
    + sizeof(struct nova_super_block));
    + PERSISTENT_BARRIER();
    +}
    +
    +static struct nova_inode *nova_init(struct super_block *sb,
    + unsigned long size)
    +{
    + unsigned long blocksize;
    + struct nova_inode *root_i, *pi;
    + struct nova_super_block *super;
    + struct nova_sb_info *sbi = NOVA_SB(sb);
    +
    + nova_info("creating an empty nova of size %lu\n", size);
    + sbi->num_blocks = ((unsigned long)(size) >> PAGE_SHIFT);
    +
    + nova_dbgv("nova: Default block size set to 4K\n");
    + sbi->blocksize = blocksize = NOVA_DEF_BLOCK_SIZE_4K;
    + nova_set_blocksize(sb, sbi->blocksize);
    +
    + if (!nova_check_size(sb, size)) {
    + nova_warn("Specified NOVA size too small 0x%lx.\n", size);
    + return ERR_PTR(-EINVAL);
    + }
    +
    + nova_dbgv("max file name len %d\n", (unsigned int)NOVA_NAME_LEN);
    +
    + super = nova_get_super(sb);
    +
    + /* clear out super-block and inode table */
    + memset_nt(super, 0, sbi->head_reserved_blocks * sbi->blocksize);
    +
    + pi = nova_get_inode_by_ino(sb, NOVA_BLOCKNODE_INO);
    + pi->nova_ino = NOVA_BLOCKNODE_INO;
    + nova_flush_buffer(pi, CACHELINE_SIZE, 1);
    +
    + sbi->nova_sb->s_size = cpu_to_le64(size);
    + sbi->nova_sb->s_blocksize = cpu_to_le32(blocksize);
    + sbi->nova_sb->s_magic = cpu_to_le32(NOVA_SUPER_MAGIC);
    + sbi->nova_sb->s_epoch_id = 0;
    +
    + nova_sync_super(sb);
    +
    + root_i = nova_get_inode_by_ino(sb, NOVA_ROOT_INO);
    + nova_dbgv("%s: Allocate root inode @ 0x%p\n", __func__, root_i);
    +
    + root_i->i_mode = cpu_to_le16(sbi->mode | S_IFDIR);
    + root_i->i_uid = cpu_to_le32(from_kuid(&init_user_ns, sbi->uid));
    + root_i->i_gid = cpu_to_le32(from_kgid(&init_user_ns, sbi->gid));
    + root_i->i_links_count = cpu_to_le16(2);
    + root_i->i_blk_type = NOVA_BLOCK_TYPE_4K;
    + root_i->i_flags = 0;
    + root_i->i_size = cpu_to_le64(sb->s_blocksize);
    + root_i->i_atime = root_i->i_mtime = root_i->i_ctime =
    + cpu_to_le32(get_seconds());
    + root_i->nova_ino = cpu_to_le64(NOVA_ROOT_INO);
    + root_i->valid = 1;
    +
    + nova_flush_buffer(root_i, sizeof(*root_i), false);
    +
    + PERSISTENT_MARK();
    + PERSISTENT_BARRIER();
    + nova_info("NOVA initialization finish\n");
    + return root_i;
    +}
    +
    +static inline void set_default_opts(struct nova_sb_info *sbi)
    +{
    + set_opt(sbi->s_mount_opt, HUGEIOREMAP);
    + set_opt(sbi->s_mount_opt, ERRORS_CONT);
    + sbi->head_reserved_blocks = HEAD_RESERVED_BLOCKS;
    + sbi->tail_reserved_blocks = TAIL_RESERVED_BLOCKS;
    + sbi->cpus = num_online_cpus();
    +}
    +
    +static void nova_root_check(struct super_block *sb, struct nova_inode *root_pi)
    +{
    + if (!S_ISDIR(le16_to_cpu(root_pi->i_mode)))
    + nova_warn("root is not a directory!\n");
    +}
    +
    +static int nova_fill_super(struct super_block *sb, void *data, int silent)
    +{
    + struct nova_sb_info *sbi = NULL;
    + struct nova_inode *root_pi;
    + struct inode *root_i = NULL;
    + unsigned long blocksize;
    + u32 random = 0;
    + int retval = -EINVAL;
    +
    + BUILD_BUG_ON(sizeof(struct nova_super_block) > NOVA_SB_SIZE);
    +
    + sbi = kzalloc(sizeof(struct nova_sb_info), GFP_KERNEL);
    + if (!sbi)
    + return -ENOMEM;
    + sbi->nova_sb = kzalloc(sizeof(struct nova_super_block), GFP_KERNEL);
    + if (!sbi->nova_sb) {
    + kfree(sbi);
    + return -ENOMEM;
    + }
    +
    + sb->s_fs_info = sbi;
    + sbi->sb = sb;
    +
    + set_default_opts(sbi);
    +
    + /* Currently the log page supports 64 journal pointer pairs */
    + if (sbi->cpus > MAX_CPUS) {
    + nova_err(sb, "NOVA needs more log pointer pages to support more than "
    + __stringify(MAX_CPUS) " cpus.\n");
    + goto out;
    + }
    +
    + retval = nova_get_nvmm_info(sb, sbi);
    + if (retval) {
    + nova_err(sb, "%s: Failed to get nvmm info.",
    + __func__);
    + goto out;
    + }
    +
    + get_random_bytes(&random, sizeof(u32));
    + atomic_set(&sbi->next_generation, random);
    +
    + /* Init with default values */
    + sbi->mode = (0755);
    + sbi->uid = current_fsuid();
    + sbi->gid = current_fsgid();
    + set_opt(sbi->s_mount_opt, HUGEIOREMAP);
    +
    + mutex_init(&sbi->s_lock);
    +
    + sbi->zeroed_page = kzalloc(PAGE_SIZE, GFP_KERNEL);
    + if (!sbi->zeroed_page) {
    + retval = -ENOMEM;
    + nova_dbg("%s: sbi->zeroed_page failed.",
    + __func__);
    + goto out;
    + }
    +
    + retval = nova_parse_options(data, sbi, 0);
    + if (retval) {
    + nova_err(sb, "%s: Failed to parse nova command line options.",
    + __func__);
    + goto out;
    + }
    +
    + /* Init a new nova instance */
    + if (sbi->s_mount_opt & NOVA_MOUNT_FORMAT) {
    + root_pi = nova_init(sb, sbi->initsize);
    + if (IS_ERR(root_pi)) {
    + nova_err(sb, "%s: root_pi error.",
    + __func__);
    +
    + goto out;
    + }
    + goto setup_sb;
    + }
    +
    + blocksize = le32_to_cpu(sbi->nova_sb->s_blocksize);
    + nova_set_blocksize(sb, blocksize);
    +
    + nova_dbg_verbose("blocksize %lu\n", blocksize);
    +
    + /* Read the root inode */
    + root_pi = nova_get_inode_by_ino(sb, NOVA_ROOT_INO);
    +
    + /* Check that the root inode is in a sane state */
    + nova_root_check(sb, root_pi);
    +
    + /* Set it all up.. */
    +setup_sb:
    + sb->s_magic = le32_to_cpu(sbi->nova_sb->s_magic);
    + sb->s_op = &nova_sops;
    + sb->s_maxbytes = nova_max_size(sb->s_blocksize_bits);
    + sb->s_time_gran = 1000000000; // 1 second.
    + sb->s_xattr = NULL;
    + sb->s_flags |= MS_NOSEC;
    +
    + root_i = nova_iget(sb, NOVA_ROOT_INO);
    + if (IS_ERR(root_i)) {
    + retval = PTR_ERR(root_i);
    + nova_err(sb, "%s: failed to get root inode",
    + __func__);
    +
    + goto out;
    + }
    +
    + sb->s_root = d_make_root(root_i);
    + if (!sb->s_root) {
    + nova_err(sb, "get nova root inode failed\n");
    + retval = -ENOMEM;
    + goto out;
    + }
    +
    + retval = 0;
    + return retval;
    +
    +out:
    + kfree(sbi->zeroed_page);
    + sbi->zeroed_page = NULL;
    +
    + kfree(sbi->nova_sb);
    + kfree(sbi);
    + nova_dbg("%s failed: return %d\n", __func__, retval);
    + return retval;
    +}
    +
    +static void nova_put_super(struct super_block *sb)
    +{
    + struct nova_sb_info *sbi = NOVA_SB(sb);
    +
    + if (sbi->virt_addr) {
    + sbi->virt_addr = NULL;
    + }
    +
    + kfree(sbi->zeroed_page);
    + nova_dbgmask = 0;
    +
    + kfree(sbi->nova_sb);
    + kfree(sbi);
    + sb->s_fs_info = NULL;
    +}
    +
    +static struct inode *nova_alloc_inode(struct super_block *sb)
    +{
    + struct nova_inode_info *vi;
    +
    + vi = kmem_cache_alloc(nova_inode_cachep, GFP_NOFS);
    + if (!vi)
    + return NULL;
    +
    + return &vi->vfs_inode;
    +}
    +
    +static void nova_i_callback(struct rcu_head *head)
    +{
    + struct inode *inode = container_of(head, struct inode, i_rcu);
    + struct nova_inode_info *vi = NOVA_I(inode);
    +
    + nova_dbg_verbose("%s: ino %lu\n", __func__, inode->i_ino);
    + kmem_cache_free(nova_inode_cachep, vi);
    +}
    +
    +static void nova_destroy_inode(struct inode *inode)
    +{
    + nova_dbgv("%s: %lu\n", __func__, inode->i_ino);
    + call_rcu(&inode->i_rcu, nova_i_callback);
    +}
    +
    +static void init_once(void *foo)
    +{
    + struct nova_inode_info *vi = foo;
    +
    + inode_init_once(&vi->vfs_inode);
    +}
    +
    +static int __init init_inodecache(void)
    +{
    + nova_inode_cachep = kmem_cache_create("nova_inode_cache",
    + sizeof(struct nova_inode_info),
    + 0, (SLAB_RECLAIM_ACCOUNT |
    + SLAB_MEM_SPREAD), init_once);
    + if (nova_inode_cachep == NULL)
    + return -ENOMEM;
    + return 0;
    +}
    +
    +static void destroy_inodecache(void)
    +{
    + /*
    + * Make sure all delayed rcu free inodes are flushed before
    + * we destroy cache.
    + */
    + rcu_barrier();
    + kmem_cache_destroy(nova_inode_cachep);
    +}
    +
    +
    +/*
    + * the super block writes are all done "on the fly", so the
    + * super block is never in a "dirty" state, so there's no need
    + * for write_super.
    + */
    +static struct super_operations nova_sops = {
    + .alloc_inode = nova_alloc_inode,
    + .destroy_inode = nova_destroy_inode,
    + .put_super = nova_put_super,
    +};
    +
    +static struct dentry *nova_mount(struct file_system_type *fs_type,
    + int flags, const char *dev_name, void *data)
    +{
    + return mount_bdev(fs_type, flags, dev_name, data, nova_fill_super);
    +}
    +
    +static struct file_system_type nova_fs_type = {
    + .owner = THIS_MODULE,
    + .name = "NOVA",
    + .mount = nova_mount,
    + .kill_sb = kill_block_super,
    +};
    +
    +static int __init init_nova_fs(void)
    +{
    + int rc = 0;
    +
    + nova_dbg("%s: %d cpus online\n", __func__, num_online_cpus());
    + if (arch_has_clwb())
    + support_clwb = 1;
    +
    + nova_info("Arch new instructions support: CLWB %s\n",
    + support_clwb ? "YES" : "NO");
    +
    + rc = init_inodecache();
    + if (rc)
    + return rc;
    +
    + rc = register_filesystem(&nova_fs_type);
    + if (rc)
    + goto out1;
    +
    + return rc;
    +
    +out1:
    + destroy_inodecache();
    + return rc;
    +}
    +
    +static void __exit exit_nova_fs(void)
    +{
    + unregister_filesystem(&nova_fs_type);
    + destroy_inodecache();
    +}
    +
    +MODULE_AUTHOR("Andiry Xu <jix024@cs.ucsd.edu>");
    +MODULE_DESCRIPTION("NOVA: NOn-Volatile memory Accelerated File System");
    +MODULE_LICENSE("GPL");
    +
    +module_init(init_nova_fs)
    +module_exit(exit_nova_fs)
    --
    2.7.4
    \
     
     \ /
      Last update: 2018-03-10 19:45    [W:4.293 / U:0.036 seconds]
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