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OpenCloudOS-Kernel/fs/exofs/dir.c

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/*
* Copyright (C) 2005, 2006
* Avishay Traeger (avishay@gmail.com)
* Copyright (C) 2008, 2009
* Boaz Harrosh <ooo@electrozaur.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 "exofs.h"
static inline unsigned exofs_chunk_size(struct inode *inode)
{
return inode->i_sb->s_blocksize;
}
static inline void exofs_put_page(struct page *page)
{
kunmap(page);
put_page(page);
}
static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
{
loff_t last_byte = inode->i_size;
last_byte -= page_nr << PAGE_SHIFT;
if (last_byte > PAGE_SIZE)
last_byte = PAGE_SIZE;
return last_byte;
}
static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
{
struct address_space *mapping = page->mapping;
struct inode *dir = mapping->host;
int err = 0;
dir->i_version++;
if (!PageUptodate(page))
SetPageUptodate(page);
if (pos+len > dir->i_size) {
i_size_write(dir, pos+len);
mark_inode_dirty(dir);
}
set_page_dirty(page);
if (IS_DIRSYNC(dir))
err = write_one_page(page);
else
unlock_page(page);
return err;
}
static bool exofs_check_page(struct page *page)
{
struct inode *dir = page->mapping->host;
unsigned chunk_size = exofs_chunk_size(dir);
char *kaddr = page_address(page);
unsigned offs, rec_len;
unsigned limit = PAGE_SIZE;
struct exofs_dir_entry *p;
char *error;
/* if the page is the last one in the directory */
if ((dir->i_size >> PAGE_SHIFT) == page->index) {
limit = dir->i_size & ~PAGE_MASK;
if (limit & (chunk_size - 1))
goto Ebadsize;
if (!limit)
goto out;
}
for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
p = (struct exofs_dir_entry *)(kaddr + offs);
rec_len = le16_to_cpu(p->rec_len);
if (rec_len < EXOFS_DIR_REC_LEN(1))
goto Eshort;
if (rec_len & 3)
goto Ealign;
if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
goto Enamelen;
if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
goto Espan;
}
if (offs != limit)
goto Eend;
out:
SetPageChecked(page);
return true;
Ebadsize:
EXOFS_ERR("ERROR [exofs_check_page]: "
"size of directory(0x%lx) is not a multiple of chunk size\n",
dir->i_ino
);
goto fail;
Eshort:
error = "rec_len is smaller than minimal";
goto bad_entry;
Ealign:
error = "unaligned directory entry";
goto bad_entry;
Enamelen:
error = "rec_len is too small for name_len";
goto bad_entry;
Espan:
error = "directory entry across blocks";
goto bad_entry;
bad_entry:
EXOFS_ERR(
"ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
"offset=%lu, inode=0x%llx, rec_len=%d, name_len=%d\n",
dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
_LLU(le64_to_cpu(p->inode_no)),
rec_len, p->name_len);
goto fail;
Eend:
p = (struct exofs_dir_entry *)(kaddr + offs);
EXOFS_ERR("ERROR [exofs_check_page]: "
"entry in directory(0x%lx) spans the page boundary"
"offset=%lu, inode=0x%llx\n",
dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
_LLU(le64_to_cpu(p->inode_no)));
fail:
SetPageError(page);
return false;
}
static struct page *exofs_get_page(struct inode *dir, unsigned long n)
{
struct address_space *mapping = dir->i_mapping;
struct page *page = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(page)) {
kmap(page);
if (unlikely(!PageChecked(page))) {
if (PageError(page) || !exofs_check_page(page))
goto fail;
}
}
return page;
fail:
exofs_put_page(page);
return ERR_PTR(-EIO);
}
static inline int exofs_match(int len, const unsigned char *name,
struct exofs_dir_entry *de)
{
if (len != de->name_len)
return 0;
if (!de->inode_no)
return 0;
return !memcmp(name, de->name, len);
}
static inline
struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
{
return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
}
static inline unsigned
exofs_validate_entry(char *base, unsigned offset, unsigned mask)
{
struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
struct exofs_dir_entry *p =
(struct exofs_dir_entry *)(base + (offset&mask));
while ((char *)p < (char *)de) {
if (p->rec_len == 0)
break;
p = exofs_next_entry(p);
}
return (char *)p - base;
}
static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
[EXOFS_FT_UNKNOWN] = DT_UNKNOWN,
[EXOFS_FT_REG_FILE] = DT_REG,
[EXOFS_FT_DIR] = DT_DIR,
[EXOFS_FT_CHRDEV] = DT_CHR,
[EXOFS_FT_BLKDEV] = DT_BLK,
[EXOFS_FT_FIFO] = DT_FIFO,
[EXOFS_FT_SOCK] = DT_SOCK,
[EXOFS_FT_SYMLINK] = DT_LNK,
};
#define S_SHIFT 12
static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
[S_IFREG >> S_SHIFT] = EXOFS_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = EXOFS_FT_DIR,
[S_IFCHR >> S_SHIFT] = EXOFS_FT_CHRDEV,
[S_IFBLK >> S_SHIFT] = EXOFS_FT_BLKDEV,
[S_IFIFO >> S_SHIFT] = EXOFS_FT_FIFO,
[S_IFSOCK >> S_SHIFT] = EXOFS_FT_SOCK,
[S_IFLNK >> S_SHIFT] = EXOFS_FT_SYMLINK,
};
static inline
void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
{
umode_t mode = inode->i_mode;
de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
}
static int
exofs_readdir(struct file *file, struct dir_context *ctx)
{
loff_t pos = ctx->pos;
struct inode *inode = file_inode(file);
unsigned int offset = pos & ~PAGE_MASK;
unsigned long n = pos >> PAGE_SHIFT;
unsigned long npages = dir_pages(inode);
unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
int need_revalidate = (file->f_version != inode->i_version);
if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
return 0;
for ( ; n < npages; n++, offset = 0) {
char *kaddr, *limit;
struct exofs_dir_entry *de;
struct page *page = exofs_get_page(inode, n);
if (IS_ERR(page)) {
EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
inode->i_ino);
ctx->pos += PAGE_SIZE - offset;
return PTR_ERR(page);
}
kaddr = page_address(page);
if (unlikely(need_revalidate)) {
if (offset) {
offset = exofs_validate_entry(kaddr, offset,
chunk_mask);
ctx->pos = (n<<PAGE_SHIFT) + offset;
}
file->f_version = inode->i_version;
need_revalidate = 0;
}
de = (struct exofs_dir_entry *)(kaddr + offset);
limit = kaddr + exofs_last_byte(inode, n) -
EXOFS_DIR_REC_LEN(1);
for (; (char *)de <= limit; de = exofs_next_entry(de)) {
if (de->rec_len == 0) {
EXOFS_ERR("ERROR: "
"zero-length entry in directory(0x%lx)\n",
inode->i_ino);
exofs_put_page(page);
return -EIO;
}
if (de->inode_no) {
unsigned char t;
if (de->file_type < EXOFS_FT_MAX)
t = exofs_filetype_table[de->file_type];
else
t = DT_UNKNOWN;
if (!dir_emit(ctx, de->name, de->name_len,
le64_to_cpu(de->inode_no),
t)) {
exofs_put_page(page);
return 0;
}
}
ctx->pos += le16_to_cpu(de->rec_len);
}
exofs_put_page(page);
}
return 0;
}
struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
struct dentry *dentry, struct page **res_page)
{
const unsigned char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
unsigned long start, n;
unsigned long npages = dir_pages(dir);
struct page *page = NULL;
struct exofs_i_info *oi = exofs_i(dir);
struct exofs_dir_entry *de;
if (npages == 0)
goto out;
*res_page = NULL;
start = oi->i_dir_start_lookup;
if (start >= npages)
start = 0;
n = start;
do {
char *kaddr;
page = exofs_get_page(dir, n);
if (!IS_ERR(page)) {
kaddr = page_address(page);
de = (struct exofs_dir_entry *) kaddr;
kaddr += exofs_last_byte(dir, n) - reclen;
while ((char *) de <= kaddr) {
if (de->rec_len == 0) {
EXOFS_ERR("ERROR: zero-length entry in "
"directory(0x%lx)\n",
dir->i_ino);
exofs_put_page(page);
goto out;
}
if (exofs_match(namelen, name, de))
goto found;
de = exofs_next_entry(de);
}
exofs_put_page(page);
}
if (++n >= npages)
n = 0;
} while (n != start);
out:
return NULL;
found:
*res_page = page;
oi->i_dir_start_lookup = n;
return de;
}
struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
{
struct page *page = exofs_get_page(dir, 0);
struct exofs_dir_entry *de = NULL;
if (!IS_ERR(page)) {
de = exofs_next_entry(
(struct exofs_dir_entry *)page_address(page));
*p = page;
}
return de;
}
ino_t exofs_parent_ino(struct dentry *child)
{
struct page *page;
struct exofs_dir_entry *de;
ino_t ino;
de = exofs_dotdot(d_inode(child), &page);
if (!de)
return 0;
ino = le64_to_cpu(de->inode_no);
exofs_put_page(page);
return ino;
}
ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
{
ino_t res = 0;
struct exofs_dir_entry *de;
struct page *page;
de = exofs_find_entry(dir, dentry, &page);
if (de) {
res = le64_to_cpu(de->inode_no);
exofs_put_page(page);
}
return res;
}
int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
struct page *page, struct inode *inode)
{
loff_t pos = page_offset(page) +
(char *) de - (char *) page_address(page);
unsigned len = le16_to_cpu(de->rec_len);
int err;
lock_page(page);
err = exofs_write_begin(NULL, page->mapping, pos, len, 0, &page, NULL);
if (err)
EXOFS_ERR("exofs_set_link: exofs_write_begin FAILED => %d\n",
err);
de->inode_no = cpu_to_le64(inode->i_ino);
exofs_set_de_type(de, inode);
if (likely(!err))
err = exofs_commit_chunk(page, pos, len);
exofs_put_page(page);
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
return err;
}
int exofs_add_link(struct dentry *dentry, struct inode *inode)
{
struct inode *dir = d_inode(dentry->d_parent);
const unsigned char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
unsigned chunk_size = exofs_chunk_size(dir);
unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
unsigned short rec_len, name_len;
struct page *page = NULL;
struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
struct exofs_dir_entry *de;
unsigned long npages = dir_pages(dir);
unsigned long n;
char *kaddr;
loff_t pos;
int err;
for (n = 0; n <= npages; n++) {
char *dir_end;
page = exofs_get_page(dir, n);
err = PTR_ERR(page);
if (IS_ERR(page))
goto out;
lock_page(page);
kaddr = page_address(page);
dir_end = kaddr + exofs_last_byte(dir, n);
de = (struct exofs_dir_entry *)kaddr;
kaddr += PAGE_SIZE - reclen;
while ((char *)de <= kaddr) {
if ((char *)de == dir_end) {
name_len = 0;
rec_len = chunk_size;
de->rec_len = cpu_to_le16(chunk_size);
de->inode_no = 0;
goto got_it;
}
if (de->rec_len == 0) {
EXOFS_ERR("ERROR: exofs_add_link: "
"zero-length entry in directory(0x%lx)\n",
inode->i_ino);
err = -EIO;
goto out_unlock;
}
err = -EEXIST;
if (exofs_match(namelen, name, de))
goto out_unlock;
name_len = EXOFS_DIR_REC_LEN(de->name_len);
rec_len = le16_to_cpu(de->rec_len);
if (!de->inode_no && rec_len >= reclen)
goto got_it;
if (rec_len >= name_len + reclen)
goto got_it;
de = (struct exofs_dir_entry *) ((char *) de + rec_len);
}
unlock_page(page);
exofs_put_page(page);
}
EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=0x%lx\n",
dentry, inode->i_ino);
return -EINVAL;
got_it:
pos = page_offset(page) +
(char *)de - (char *)page_address(page);
err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
&page, NULL);
if (err)
goto out_unlock;
if (de->inode_no) {
struct exofs_dir_entry *de1 =
(struct exofs_dir_entry *)((char *)de + name_len);
de1->rec_len = cpu_to_le16(rec_len - name_len);
de->rec_len = cpu_to_le16(name_len);
de = de1;
}
de->name_len = namelen;
memcpy(de->name, name, namelen);
de->inode_no = cpu_to_le64(inode->i_ino);
exofs_set_de_type(de, inode);
err = exofs_commit_chunk(page, pos, rec_len);
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
sbi->s_numfiles++;
out_put:
exofs_put_page(page);
out:
return err;
out_unlock:
unlock_page(page);
goto out_put;
}
int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
char *kaddr = page_address(page);
unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
loff_t pos;
struct exofs_dir_entry *pde = NULL;
struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
int err;
while (de < dir) {
if (de->rec_len == 0) {
EXOFS_ERR("ERROR: exofs_delete_entry:"
"zero-length entry in directory(0x%lx)\n",
inode->i_ino);
err = -EIO;
goto out;
}
pde = de;
de = exofs_next_entry(de);
}
if (pde)
from = (char *)pde - (char *)page_address(page);
pos = page_offset(page) + from;
lock_page(page);
err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
&page, NULL);
if (err)
EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILED => %d\n",
err);
if (pde)
pde->rec_len = cpu_to_le16(to - from);
dir->inode_no = 0;
if (likely(!err))
err = exofs_commit_chunk(page, pos, to - from);
inode->i_ctime = inode->i_mtime = current_time(inode);
mark_inode_dirty(inode);
sbi->s_numfiles--;
out:
exofs_put_page(page);
return err;
}
/* kept aligned on 4 bytes */
#define THIS_DIR ".\0\0"
#define PARENT_DIR "..\0"
int exofs_make_empty(struct inode *inode, struct inode *parent)
{
struct address_space *mapping = inode->i_mapping;
struct page *page = grab_cache_page(mapping, 0);
unsigned chunk_size = exofs_chunk_size(inode);
struct exofs_dir_entry *de;
int err;
void *kaddr;
if (!page)
return -ENOMEM;
err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
&page, NULL);
if (err) {
unlock_page(page);
goto fail;
}
kaddr = kmap_atomic(page);
de = (struct exofs_dir_entry *)kaddr;
de->name_len = 1;
de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
de->inode_no = cpu_to_le64(inode->i_ino);
exofs_set_de_type(de, inode);
de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
de->name_len = 2;
de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
de->inode_no = cpu_to_le64(parent->i_ino);
memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
exofs_set_de_type(de, inode);
kunmap_atomic(kaddr);
err = exofs_commit_chunk(page, 0, chunk_size);
fail:
put_page(page);
return err;
}
int exofs_empty_dir(struct inode *inode)
{
struct page *page = NULL;
unsigned long i, npages = dir_pages(inode);
for (i = 0; i < npages; i++) {
char *kaddr;
struct exofs_dir_entry *de;
page = exofs_get_page(inode, i);
if (IS_ERR(page))
continue;
kaddr = page_address(page);
de = (struct exofs_dir_entry *)kaddr;
kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
while ((char *)de <= kaddr) {
if (de->rec_len == 0) {
EXOFS_ERR("ERROR: exofs_empty_dir: "
"zero-length directory entry"
"kaddr=%p, de=%p\n", kaddr, de);
goto not_empty;
}
if (de->inode_no != 0) {
/* check for . and .. */
if (de->name[0] != '.')
goto not_empty;
if (de->name_len > 2)
goto not_empty;
if (de->name_len < 2) {
if (le64_to_cpu(de->inode_no) !=
inode->i_ino)
goto not_empty;
} else if (de->name[1] != '.')
goto not_empty;
}
de = exofs_next_entry(de);
}
exofs_put_page(page);
}
return 1;
not_empty:
exofs_put_page(page);
return 0;
}
const struct file_operations exofs_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.iterate_shared = exofs_readdir,
};
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