staging: erofs: add inode operations

This adds core functions to get, read an inode.

Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gao Xiang 2018-07-26 20:21:48 +08:00 committed by Greg Kroah-Hartman
parent 81781b02f9
commit 431339ba90

View File

@ -0,0 +1,210 @@
// SPDX-License-Identifier: GPL-2.0
/*
* linux/drivers/staging/erofs/inode.c
*
* Copyright (C) 2017-2018 HUAWEI, Inc.
* http://www.huawei.com/
* Created by Gao Xiang <gaoxiang25@huawei.com>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of the Linux
* distribution for more details.
*/
#include "internal.h"
/* no locking */
static int read_inode(struct inode *inode, void *data)
{
struct erofs_vnode *vi = EROFS_V(inode);
struct erofs_inode_v1 *v1 = data;
const unsigned advise = le16_to_cpu(v1->i_advise);
vi->data_mapping_mode = __inode_data_mapping(advise);
if (unlikely(vi->data_mapping_mode >= EROFS_INODE_LAYOUT_MAX)) {
errln("unknown data mapping mode %u of nid %llu",
vi->data_mapping_mode, vi->nid);
DBG_BUGON(1);
return -EIO;
}
if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
struct erofs_inode_v2 *v2 = data;
vi->inode_isize = sizeof(struct erofs_inode_v2);
vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
inode->i_mode = le16_to_cpu(v2->i_mode);
i_uid_write(inode, le32_to_cpu(v2->i_uid));
i_gid_write(inode, le32_to_cpu(v2->i_gid));
set_nlink(inode, le32_to_cpu(v2->i_nlink));
/* ns timestamp */
inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
le64_to_cpu(v2->i_ctime);
inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
le32_to_cpu(v2->i_ctime_nsec);
inode->i_size = le64_to_cpu(v2->i_size);
} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
vi->inode_isize = sizeof(struct erofs_inode_v1);
vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
inode->i_mode = le16_to_cpu(v1->i_mode);
i_uid_write(inode, le16_to_cpu(v1->i_uid));
i_gid_write(inode, le16_to_cpu(v1->i_gid));
set_nlink(inode, le16_to_cpu(v1->i_nlink));
/* use build time to derive all file time */
inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
sbi->build_time;
inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
sbi->build_time_nsec;
inode->i_size = le32_to_cpu(v1->i_size);
} else {
errln("unsupported on-disk inode version %u of nid %llu",
__inode_version(advise), vi->nid);
DBG_BUGON(1);
return -EIO;
}
/* measure inode.i_blocks as the generic filesystem */
inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;
return 0;
}
/*
* try_lock can be required since locking order is:
* file data(fs_inode)
* meta(bd_inode)
* but the majority of the callers is "iget",
* in that case we are pretty sure no deadlock since
* no data operations exist. However I tend to
* try_lock since it takes no much overhead and
* will success immediately.
*/
static int fill_inline_data(struct inode *inode, void *data, unsigned m_pofs)
{
struct erofs_vnode *vi = EROFS_V(inode);
int mode = vi->data_mapping_mode;
DBG_BUGON(mode >= EROFS_INODE_LAYOUT_MAX);
/* should be inode inline C */
if (mode != EROFS_INODE_LAYOUT_INLINE)
return 0;
/* fast symlink (following ext4) */
if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
char *lnk = kmalloc(inode->i_size + 1, GFP_KERNEL);
if (unlikely(lnk == NULL))
return -ENOMEM;
m_pofs += vi->inode_isize + vi->xattr_isize;
BUG_ON(m_pofs + inode->i_size > PAGE_SIZE);
/* get in-page inline data */
memcpy(lnk, data + m_pofs, inode->i_size);
lnk[inode->i_size] = '\0';
inode->i_link = lnk;
set_inode_fast_symlink(inode);
}
return -EAGAIN;
}
static int fill_inode(struct inode *inode, int isdir)
{
struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
struct erofs_vnode *vi = EROFS_V(inode);
struct page *page;
void *data;
int err;
erofs_blk_t blkaddr;
unsigned ofs;
blkaddr = erofs_blknr(iloc(sbi, vi->nid));
ofs = erofs_blkoff(iloc(sbi, vi->nid));
debugln("%s, reading inode nid %llu at %u of blkaddr %u",
__func__, vi->nid, ofs, blkaddr);
page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
if (IS_ERR(page)) {
errln("failed to get inode (nid: %llu) page, err %ld",
vi->nid, PTR_ERR(page));
return PTR_ERR(page);
}
BUG_ON(!PageUptodate(page));
data = page_address(page);
err = read_inode(inode, data + ofs);
if (!err) {
/* setup the new inode */
if (S_ISREG(inode->i_mode)) {
inode->i_fop = &generic_ro_fops;
} else if (S_ISDIR(inode->i_mode)) {
inode->i_op =
&erofs_dir_iops;
inode->i_fop = &erofs_dir_fops;
} else if (S_ISLNK(inode->i_mode)) {
/* by default, page_get_link is used for symlink */
inode->i_op =
&page_symlink_inode_operations;
inode_nohighmem(inode);
} else {
err = -EIO;
goto out_unlock;
}
if (is_inode_layout_compression(inode)) {
err = -ENOTSUPP;
goto out_unlock;
}
inode->i_mapping->a_ops = &erofs_raw_access_aops;
/* fill last page if inline data is available */
fill_inline_data(inode, data, ofs);
}
out_unlock:
unlock_page(page);
put_page(page);
return err;
}
struct inode *erofs_iget(struct super_block *sb,
erofs_nid_t nid, bool isdir)
{
struct inode *inode = iget_locked(sb, nid);
if (unlikely(inode == NULL))
return ERR_PTR(-ENOMEM);
if (inode->i_state & I_NEW) {
int err;
struct erofs_vnode *vi = EROFS_V(inode);
vi->nid = nid;
err = fill_inode(inode, isdir);
if (likely(!err))
unlock_new_inode(inode);
else {
iget_failed(inode);
inode = ERR_PTR(err);
}
}
return inode;
}