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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
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