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linux/fs/exofs/dir.c
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00

662 lines
16 KiB
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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, 1);
else
unlock_page(page);
return err;
}
static void 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;
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%llu, 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:
SetPageChecked(page);
SetPageError(page);
}
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 (!PageChecked(page))
exofs_check_page(page);
if (PageError(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,
AOP_FLAG_UNINTERRUPTIBLE, &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;
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;
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;
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 = exofs_readdir,
};
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