Re: [RFC v2 06/83] Add inode get/read methods.

Darrick J. Wong
2018-04-23T06:18:45Z

[haaa, I finally found time to read more of these]

On Sat, Mar 10, 2018 at 10:17:47AM -0800, Andiry Xu wrote:
> From: Andiry Xu <jix024@cs.ucsd.edu>
>
> These routines are incomplete and currently only support reserved inodes,
> whose addresses are fixed. This is necessary for fill_super to work.
> File/dir operations are left NULL.
>
> Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
> ---
> fs/nova/inode.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/nova/inode.h | 3 +
> 2 files changed, 179 insertions(+)
> create mode 100644 fs/nova/inode.c
>
> diff --git a/fs/nova/inode.c b/fs/nova/inode.c
> new file mode 100644
> index 0000000..bfdc5dc
> --- /dev/null
> +++ b/fs/nova/inode.c
> @@ -0,0 +1,176 @@
> +/*
> + * BRIEF DESCRIPTION
> + *
> + * Inode methods (allocate/free/read/write).
> + *
> + * 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 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/fs.h>
> +#include <linux/aio.h>
> +#include <linux/highuid.h>
> +#include <linux/module.h>
> +#include <linux/mpage.h>
> +#include <linux/backing-dev.h>
> +#include <linux/types.h>
> +#include <linux/ratelimit.h>
> +#include "nova.h"
> +#include "inode.h"
> +
> +unsigned int blk_type_to_shift[NOVA_BLOCK_TYPE_MAX] = {12, 21, 30};
> +uint32_t blk_type_to_size[NOVA_BLOCK_TYPE_MAX] = {0x1000, 0x200000, 0x40000000};
> +
> +void nova_set_inode_flags(struct inode *inode, struct nova_inode *pi,
> + unsigned int flags)
> +{
> + inode->i_flags &=
> + ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC);
> + if (flags & FS_SYNC_FL)
> + inode->i_flags |= S_SYNC;
> + if (flags & FS_APPEND_FL)
> + inode->i_flags |= S_APPEND;
> + if (flags & FS_IMMUTABLE_FL)
> + inode->i_flags |= S_IMMUTABLE;
> + if (flags & FS_NOATIME_FL)
> + inode->i_flags |= S_NOATIME;
> + if (flags & FS_DIRSYNC_FL)
> + inode->i_flags |= S_DIRSYNC;
> + if (!pi->i_xattr)
> + inode_has_no_xattr(inode);
> + inode->i_flags |= S_DAX;
> +}
> +
> +/* copy persistent state to struct inode */
> +static int nova_read_inode(struct super_block *sb, struct inode *inode,
> + u64 pi_addr)
> +{
> + struct nova_inode_info *si = NOVA_I(inode);
> + struct nova_inode *pi, fake_pi;
> + struct nova_inode_info_header *sih = &si->header;
> + int ret = -EIO;
> + unsigned long ino;
> +
> + ret = nova_get_reference(sb, pi_addr, &fake_pi,
> + (void **)&pi, sizeof(struct nova_inode));
> + if (ret) {
> + nova_dbg("%s: read pi @ 0x%llx failed\n",
> + __func__, pi_addr);
> + goto bad_inode;
> + }
> +
> + inode->i_mode = sih->i_mode;

Hm, do you validate the on-pmem metadata as it's read in? What if
i_mode is garbage?

> + i_uid_write(inode, le32_to_cpu(pi->i_uid));
> + i_gid_write(inode, le32_to_cpu(pi->i_gid));
> +// set_nlink(inode, le16_to_cpu(pi->i_links_count));

C++ comment?

> + inode->i_generation = le32_to_cpu(pi->i_generation);
> + nova_set_inode_flags(inode, pi, le32_to_cpu(pi->i_flags));
> + ino = inode->i_ino;
> +
> + /* check if the inode is active. */
> + if (inode->i_mode == 0 || pi->deleted == 1) {
> + /* this inode is deleted */
> + ret = -ESTALE;
> + goto bad_inode;
> + }
> +
> + inode->i_blocks = sih->i_blocks;

Not le64_to_cpu(sih->i_blocks)? Or is that somewhere else I'm
missing...

> +
> + switch (inode->i_mode & S_IFMT) {
> + case S_IFREG:
> + break;
> + case S_IFDIR:
> + break;
> + case S_IFLNK:
> + break;
> + default:
> + init_special_inode(inode, inode->i_mode,
> + le32_to_cpu(pi->dev.rdev));
> + break;
> + }
> +
> + /* Update size and time after rebuild the tree */
> + inode->i_size = le64_to_cpu(sih->i_size);

FWIW the type of i_size is loff_t, which is an unsigned type. Despite
this, the VFS does not support files with negative sizes... which means
that this probably ought to check for that.

--D

> + inode->i_atime.tv_sec = (__s32)le32_to_cpu(pi->i_atime);
> + inode->i_ctime.tv_sec = (__s32)le32_to_cpu(pi->i_ctime);
> + inode->i_mtime.tv_sec = (__s32)le32_to_cpu(pi->i_mtime);
> + inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec =
> + inode->i_ctime.tv_nsec = 0;
> + set_nlink(inode, le16_to_cpu(pi->i_links_count));
> + return 0;
> +
> +bad_inode:
> + make_bad_inode(inode);
> + return ret;
> +}
> +
> +/* Get the address in PMEM of an inode by inode number. Allocate additional
> + * block to store additional inodes if necessary.
> + */
> +int nova_get_inode_address(struct super_block *sb, u64 ino,
> + u64 *pi_addr, int extendable)
> +{
> + if (ino < NOVA_NORMAL_INODE_START) {
> + *pi_addr = nova_get_reserved_inode_addr(sb, ino);
> + return 0;
> + }
> +
> + *pi_addr = 0;
> + return 0;
> +}
> +
> +struct inode *nova_iget(struct super_block *sb, unsigned long ino)
> +{
> + struct nova_inode_info *si;
> + struct inode *inode;
> + u64 pi_addr;
> + int err;
> +
> + inode = iget_locked(sb, ino);
> + if (unlikely(!inode))
> + return ERR_PTR(-ENOMEM);
> + if (!(inode->i_state & I_NEW))
> + return inode;
> +
> + si = NOVA_I(inode);
> +
> + nova_dbgv("%s: inode %lu\n", __func__, ino);
> +
> + err = nova_get_inode_address(sb, ino, &pi_addr, 0);
> + if (err) {
> + nova_dbg("%s: get inode %lu address failed %d\n",
> + __func__, ino, err);
> + goto fail;
> + }
> +
> + if (pi_addr == 0) {
> + nova_dbg("%s: failed to get pi_addr for inode %lu\n",
> + __func__, ino);
> + err = -EACCES;
> + goto fail;
> + }
> +
> + err = nova_read_inode(sb, inode, pi_addr);
> + if (unlikely(err)) {
> + nova_dbg("%s: failed to read inode %lu\n", __func__, ino);
> + goto fail;
> +
> + }
> +
> + inode->i_ino = ino;
> +
> + unlock_new_inode(inode);
> + return inode;
> +fail:
> + iget_failed(inode);
> + return ERR_PTR(err);
> +}
> +
> diff --git a/fs/nova/inode.h b/fs/nova/inode.h
> index f9187e3..dbd5256 100644
> --- a/fs/nova/inode.h
> +++ b/fs/nova/inode.h
> @@ -184,4 +184,7 @@ static inline int nova_persist_inode(struct nova_inode *pi)
> return 0;
> }
>
> +int nova_get_inode_address(struct super_block *sb, u64 ino,
> + u64 *pi_addr, int extendable);
> +struct inode *nova_iget(struct super_block *sb, unsigned long ino);
> #endif
> --
> 2.7.4
>