linux/fs/f2fs/dir.c

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/*
* fs/f2fs/dir.c
*
* Copyright (c) 2012 Samsung Electronics Co., Ltd.
* http://www.samsung.com/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/fs.h>
#include <linux/f2fs_fs.h>
#include "f2fs.h"
#include "node.h"
#include "acl.h"
static unsigned long dir_blocks(struct inode *inode)
{
return ((unsigned long long) (i_size_read(inode) + PAGE_CACHE_SIZE - 1))
>> PAGE_CACHE_SHIFT;
}
static unsigned int dir_buckets(unsigned int level)
{
if (level < MAX_DIR_HASH_DEPTH / 2)
return 1 << level;
else
return 1 << ((MAX_DIR_HASH_DEPTH / 2) - 1);
}
static unsigned int bucket_blocks(unsigned int level)
{
if (level < MAX_DIR_HASH_DEPTH / 2)
return 2;
else
return 4;
}
static unsigned char f2fs_filetype_table[F2FS_FT_MAX] = {
[F2FS_FT_UNKNOWN] = DT_UNKNOWN,
[F2FS_FT_REG_FILE] = DT_REG,
[F2FS_FT_DIR] = DT_DIR,
[F2FS_FT_CHRDEV] = DT_CHR,
[F2FS_FT_BLKDEV] = DT_BLK,
[F2FS_FT_FIFO] = DT_FIFO,
[F2FS_FT_SOCK] = DT_SOCK,
[F2FS_FT_SYMLINK] = DT_LNK,
};
#define S_SHIFT 12
static unsigned char f2fs_type_by_mode[S_IFMT >> S_SHIFT] = {
[S_IFREG >> S_SHIFT] = F2FS_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = F2FS_FT_DIR,
[S_IFCHR >> S_SHIFT] = F2FS_FT_CHRDEV,
[S_IFBLK >> S_SHIFT] = F2FS_FT_BLKDEV,
[S_IFIFO >> S_SHIFT] = F2FS_FT_FIFO,
[S_IFSOCK >> S_SHIFT] = F2FS_FT_SOCK,
[S_IFLNK >> S_SHIFT] = F2FS_FT_SYMLINK,
};
static void set_de_type(struct f2fs_dir_entry *de, struct inode *inode)
{
mode_t mode = inode->i_mode;
de->file_type = f2fs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
}
static unsigned long dir_block_index(unsigned int level, unsigned int idx)
{
unsigned long i;
unsigned long bidx = 0;
for (i = 0; i < level; i++)
bidx += dir_buckets(i) * bucket_blocks(i);
bidx += idx * bucket_blocks(level);
return bidx;
}
static bool early_match_name(const char *name, int namelen,
f2fs_hash_t namehash, struct f2fs_dir_entry *de)
{
if (le16_to_cpu(de->name_len) != namelen)
return false;
if (de->hash_code != namehash)
return false;
return true;
}
static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
const char *name, int namelen, int *max_slots,
f2fs_hash_t namehash, struct page **res_page)
{
struct f2fs_dir_entry *de;
unsigned long bit_pos, end_pos, next_pos;
struct f2fs_dentry_block *dentry_blk = kmap(dentry_page);
int slots;
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK, 0);
while (bit_pos < NR_DENTRY_IN_BLOCK) {
de = &dentry_blk->dentry[bit_pos];
slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
if (early_match_name(name, namelen, namehash, de)) {
if (!memcmp(dentry_blk->filename[bit_pos],
name, namelen)) {
*res_page = dentry_page;
goto found;
}
}
next_pos = bit_pos + slots;
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK, next_pos);
if (bit_pos >= NR_DENTRY_IN_BLOCK)
end_pos = NR_DENTRY_IN_BLOCK;
else
end_pos = bit_pos;
if (*max_slots < end_pos - next_pos)
*max_slots = end_pos - next_pos;
}
de = NULL;
kunmap(dentry_page);
found:
return de;
}
static struct f2fs_dir_entry *find_in_level(struct inode *dir,
unsigned int level, const char *name, int namelen,
f2fs_hash_t namehash, struct page **res_page)
{
int s = GET_DENTRY_SLOTS(namelen);
unsigned int nbucket, nblock;
unsigned int bidx, end_block;
struct page *dentry_page;
struct f2fs_dir_entry *de = NULL;
bool room = false;
int max_slots = 0;
BUG_ON(level > MAX_DIR_HASH_DEPTH);
nbucket = dir_buckets(level);
nblock = bucket_blocks(level);
bidx = dir_block_index(level, le32_to_cpu(namehash) % nbucket);
end_block = bidx + nblock;
for (; bidx < end_block; bidx++) {
/* no need to allocate new dentry pages to all the indices */
dentry_page = find_data_page(dir, bidx);
if (IS_ERR(dentry_page)) {
room = true;
continue;
}
de = find_in_block(dentry_page, name, namelen,
&max_slots, namehash, res_page);
if (de)
break;
if (max_slots >= s)
room = true;
f2fs_put_page(dentry_page, 0);
}
if (!de && room && F2FS_I(dir)->chash != namehash) {
F2FS_I(dir)->chash = namehash;
F2FS_I(dir)->clevel = level;
}
return de;
}
/*
* Find an entry in the specified directory with the wanted name.
* It returns the page where the entry was found (as a parameter - res_page),
* and the entry itself. Page is returned mapped and unlocked.
* Entry is guaranteed to be valid.
*/
struct f2fs_dir_entry *f2fs_find_entry(struct inode *dir,
struct qstr *child, struct page **res_page)
{
const char *name = child->name;
int namelen = child->len;
unsigned long npages = dir_blocks(dir);
struct f2fs_dir_entry *de = NULL;
f2fs_hash_t name_hash;
unsigned int max_depth;
unsigned int level;
if (npages == 0)
return NULL;
*res_page = NULL;
name_hash = f2fs_dentry_hash(name, namelen);
max_depth = F2FS_I(dir)->i_current_depth;
for (level = 0; level < max_depth; level++) {
de = find_in_level(dir, level, name,
namelen, name_hash, res_page);
if (de)
break;
}
if (!de && F2FS_I(dir)->chash != name_hash) {
F2FS_I(dir)->chash = name_hash;
F2FS_I(dir)->clevel = level - 1;
}
return de;
}
struct f2fs_dir_entry *f2fs_parent_dir(struct inode *dir, struct page **p)
{
struct page *page = NULL;
struct f2fs_dir_entry *de = NULL;
struct f2fs_dentry_block *dentry_blk = NULL;
page = get_lock_data_page(dir, 0);
if (IS_ERR(page))
return NULL;
dentry_blk = kmap(page);
de = &dentry_blk->dentry[1];
*p = page;
unlock_page(page);
return de;
}
ino_t f2fs_inode_by_name(struct inode *dir, struct qstr *qstr)
{
ino_t res = 0;
struct f2fs_dir_entry *de;
struct page *page;
de = f2fs_find_entry(dir, qstr, &page);
if (de) {
res = le32_to_cpu(de->ino);
kunmap(page);
f2fs_put_page(page, 0);
}
return res;
}
void f2fs_set_link(struct inode *dir, struct f2fs_dir_entry *de,
struct page *page, struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
mutex_lock_op(sbi, DENTRY_OPS);
lock_page(page);
wait_on_page_writeback(page);
de->ino = cpu_to_le32(inode->i_ino);
set_de_type(de, inode);
kunmap(page);
set_page_dirty(page);
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
mark_inode_dirty(dir);
/* update parent inode number before releasing dentry page */
F2FS_I(inode)->i_pino = dir->i_ino;
f2fs_put_page(page, 1);
mutex_unlock_op(sbi, DENTRY_OPS);
}
void init_dent_inode(struct dentry *dentry, struct page *ipage)
{
struct f2fs_node *rn;
if (IS_ERR(ipage))
return;
wait_on_page_writeback(ipage);
/* copy dentry info. to this inode page */
rn = (struct f2fs_node *)page_address(ipage);
rn->i.i_namelen = cpu_to_le32(dentry->d_name.len);
memcpy(rn->i.i_name, dentry->d_name.name, dentry->d_name.len);
set_page_dirty(ipage);
}
static int init_inode_metadata(struct inode *inode, struct dentry *dentry)
{
struct inode *dir = dentry->d_parent->d_inode;
if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
int err;
err = new_inode_page(inode, dentry);
if (err)
return err;
if (S_ISDIR(inode->i_mode)) {
err = f2fs_make_empty(inode, dir);
if (err) {
remove_inode_page(inode);
return err;
}
}
err = f2fs_init_acl(inode, dir);
if (err) {
remove_inode_page(inode);
return err;
}
} else {
struct page *ipage;
ipage = get_node_page(F2FS_SB(dir->i_sb), inode->i_ino);
if (IS_ERR(ipage))
return PTR_ERR(ipage);
set_cold_node(inode, ipage);
init_dent_inode(dentry, ipage);
f2fs_put_page(ipage, 1);
}
if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK)) {
inc_nlink(inode);
f2fs_write_inode(inode, NULL);
}
return 0;
}
static void update_parent_metadata(struct inode *dir, struct inode *inode,
unsigned int current_depth)
{
bool need_dir_update = false;
if (is_inode_flag_set(F2FS_I(inode), FI_NEW_INODE)) {
if (S_ISDIR(inode->i_mode)) {
inc_nlink(dir);
need_dir_update = true;
}
clear_inode_flag(F2FS_I(inode), FI_NEW_INODE);
}
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
if (F2FS_I(dir)->i_current_depth != current_depth) {
F2FS_I(dir)->i_current_depth = current_depth;
need_dir_update = true;
}
if (need_dir_update)
f2fs_write_inode(dir, NULL);
else
mark_inode_dirty(dir);
if (is_inode_flag_set(F2FS_I(inode), FI_INC_LINK))
clear_inode_flag(F2FS_I(inode), FI_INC_LINK);
}
static int room_for_filename(struct f2fs_dentry_block *dentry_blk, int slots)
{
int bit_start = 0;
int zero_start, zero_end;
next:
zero_start = find_next_zero_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
bit_start);
if (zero_start >= NR_DENTRY_IN_BLOCK)
return NR_DENTRY_IN_BLOCK;
zero_end = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
zero_start);
if (zero_end - zero_start >= slots)
return zero_start;
bit_start = zero_end + 1;
if (zero_end + 1 >= NR_DENTRY_IN_BLOCK)
return NR_DENTRY_IN_BLOCK;
goto next;
}
int f2fs_add_link(struct dentry *dentry, struct inode *inode)
{
unsigned int bit_pos;
unsigned int level;
unsigned int current_depth;
unsigned long bidx, block;
f2fs_hash_t dentry_hash;
struct f2fs_dir_entry *de;
unsigned int nbucket, nblock;
struct inode *dir = dentry->d_parent->d_inode;
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
const char *name = dentry->d_name.name;
int namelen = dentry->d_name.len;
struct page *dentry_page = NULL;
struct f2fs_dentry_block *dentry_blk = NULL;
int slots = GET_DENTRY_SLOTS(namelen);
int err = 0;
int i;
dentry_hash = f2fs_dentry_hash(name, dentry->d_name.len);
level = 0;
current_depth = F2FS_I(dir)->i_current_depth;
if (F2FS_I(dir)->chash == dentry_hash) {
level = F2FS_I(dir)->clevel;
F2FS_I(dir)->chash = 0;
}
start:
if (current_depth == MAX_DIR_HASH_DEPTH)
return -ENOSPC;
/* Increase the depth, if required */
if (level == current_depth)
++current_depth;
nbucket = dir_buckets(level);
nblock = bucket_blocks(level);
bidx = dir_block_index(level, (le32_to_cpu(dentry_hash) % nbucket));
for (block = bidx; block <= (bidx + nblock - 1); block++) {
mutex_lock_op(sbi, DENTRY_OPS);
dentry_page = get_new_data_page(dir, block, true);
if (IS_ERR(dentry_page)) {
mutex_unlock_op(sbi, DENTRY_OPS);
return PTR_ERR(dentry_page);
}
dentry_blk = kmap(dentry_page);
bit_pos = room_for_filename(dentry_blk, slots);
if (bit_pos < NR_DENTRY_IN_BLOCK)
goto add_dentry;
kunmap(dentry_page);
f2fs_put_page(dentry_page, 1);
mutex_unlock_op(sbi, DENTRY_OPS);
}
/* Move to next level to find the empty slot for new dentry */
++level;
goto start;
add_dentry:
err = init_inode_metadata(inode, dentry);
if (err)
goto fail;
wait_on_page_writeback(dentry_page);
de = &dentry_blk->dentry[bit_pos];
de->hash_code = dentry_hash;
de->name_len = cpu_to_le16(namelen);
memcpy(dentry_blk->filename[bit_pos], name, namelen);
de->ino = cpu_to_le32(inode->i_ino);
set_de_type(de, inode);
for (i = 0; i < slots; i++)
test_and_set_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
set_page_dirty(dentry_page);
update_parent_metadata(dir, inode, current_depth);
/* update parent inode number before releasing dentry page */
F2FS_I(inode)->i_pino = dir->i_ino;
fail:
kunmap(dentry_page);
f2fs_put_page(dentry_page, 1);
mutex_unlock_op(sbi, DENTRY_OPS);
return err;
}
/*
* It only removes the dentry from the dentry page,corresponding name
* entry in name page does not need to be touched during deletion.
*/
void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
struct inode *inode)
{
struct f2fs_dentry_block *dentry_blk;
unsigned int bit_pos;
struct address_space *mapping = page->mapping;
struct inode *dir = mapping->host;
struct f2fs_sb_info *sbi = F2FS_SB(dir->i_sb);
int slots = GET_DENTRY_SLOTS(le16_to_cpu(dentry->name_len));
void *kaddr = page_address(page);
int i;
mutex_lock_op(sbi, DENTRY_OPS);
lock_page(page);
wait_on_page_writeback(page);
dentry_blk = (struct f2fs_dentry_block *)kaddr;
bit_pos = dentry - (struct f2fs_dir_entry *)dentry_blk->dentry;
for (i = 0; i < slots; i++)
test_and_clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
/* Let's check and deallocate this dentry page */
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
0);
kunmap(page); /* kunmap - pair of f2fs_find_entry */
set_page_dirty(page);
dir->i_ctime = dir->i_mtime = CURRENT_TIME;
if (inode && S_ISDIR(inode->i_mode)) {
drop_nlink(dir);
f2fs_write_inode(dir, NULL);
} else {
mark_inode_dirty(dir);
}
if (inode) {
inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
drop_nlink(inode);
if (S_ISDIR(inode->i_mode)) {
drop_nlink(inode);
i_size_write(inode, 0);
}
f2fs_write_inode(inode, NULL);
if (inode->i_nlink == 0)
add_orphan_inode(sbi, inode->i_ino);
}
if (bit_pos == NR_DENTRY_IN_BLOCK) {
truncate_hole(dir, page->index, page->index + 1);
clear_page_dirty_for_io(page);
ClearPageUptodate(page);
dec_page_count(sbi, F2FS_DIRTY_DENTS);
inode_dec_dirty_dents(dir);
}
f2fs_put_page(page, 1);
mutex_unlock_op(sbi, DENTRY_OPS);
}
int f2fs_make_empty(struct inode *inode, struct inode *parent)
{
struct page *dentry_page;
struct f2fs_dentry_block *dentry_blk;
struct f2fs_dir_entry *de;
void *kaddr;
dentry_page = get_new_data_page(inode, 0, true);
if (IS_ERR(dentry_page))
return PTR_ERR(dentry_page);
kaddr = kmap_atomic(dentry_page);
dentry_blk = (struct f2fs_dentry_block *)kaddr;
de = &dentry_blk->dentry[0];
de->name_len = cpu_to_le16(1);
de->hash_code = f2fs_dentry_hash(".", 1);
de->ino = cpu_to_le32(inode->i_ino);
memcpy(dentry_blk->filename[0], ".", 1);
set_de_type(de, inode);
de = &dentry_blk->dentry[1];
de->hash_code = f2fs_dentry_hash("..", 2);
de->name_len = cpu_to_le16(2);
de->ino = cpu_to_le32(parent->i_ino);
memcpy(dentry_blk->filename[1], "..", 2);
set_de_type(de, inode);
test_and_set_bit_le(0, &dentry_blk->dentry_bitmap);
test_and_set_bit_le(1, &dentry_blk->dentry_bitmap);
kunmap_atomic(kaddr);
set_page_dirty(dentry_page);
f2fs_put_page(dentry_page, 1);
return 0;
}
bool f2fs_empty_dir(struct inode *dir)
{
unsigned long bidx;
struct page *dentry_page;
unsigned int bit_pos;
struct f2fs_dentry_block *dentry_blk;
unsigned long nblock = dir_blocks(dir);
for (bidx = 0; bidx < nblock; bidx++) {
void *kaddr;
dentry_page = get_lock_data_page(dir, bidx);
if (IS_ERR(dentry_page)) {
if (PTR_ERR(dentry_page) == -ENOENT)
continue;
else
return false;
}
kaddr = kmap_atomic(dentry_page);
dentry_blk = (struct f2fs_dentry_block *)kaddr;
if (bidx == 0)
bit_pos = 2;
else
bit_pos = 0;
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
bit_pos);
kunmap_atomic(kaddr);
f2fs_put_page(dentry_page, 1);
if (bit_pos < NR_DENTRY_IN_BLOCK)
return false;
}
return true;
}
static int f2fs_readdir(struct file *file, void *dirent, filldir_t filldir)
{
unsigned long pos = file->f_pos;
struct inode *inode = file->f_dentry->d_inode;
unsigned long npages = dir_blocks(inode);
unsigned char *types = NULL;
unsigned int bit_pos = 0, start_bit_pos = 0;
int over = 0;
struct f2fs_dentry_block *dentry_blk = NULL;
struct f2fs_dir_entry *de = NULL;
struct page *dentry_page = NULL;
unsigned int n = 0;
unsigned char d_type = DT_UNKNOWN;
int slots;
types = f2fs_filetype_table;
bit_pos = (pos % NR_DENTRY_IN_BLOCK);
n = (pos / NR_DENTRY_IN_BLOCK);
for ( ; n < npages; n++) {
dentry_page = get_lock_data_page(inode, n);
if (IS_ERR(dentry_page))
continue;
start_bit_pos = bit_pos;
dentry_blk = kmap(dentry_page);
while (bit_pos < NR_DENTRY_IN_BLOCK) {
d_type = DT_UNKNOWN;
bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
bit_pos);
if (bit_pos >= NR_DENTRY_IN_BLOCK)
break;
de = &dentry_blk->dentry[bit_pos];
if (types && de->file_type < F2FS_FT_MAX)
d_type = types[de->file_type];
over = filldir(dirent,
dentry_blk->filename[bit_pos],
le16_to_cpu(de->name_len),
(n * NR_DENTRY_IN_BLOCK) + bit_pos,
le32_to_cpu(de->ino), d_type);
if (over) {
file->f_pos += bit_pos - start_bit_pos;
goto success;
}
slots = GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
bit_pos += slots;
}
bit_pos = 0;
file->f_pos = (n + 1) * NR_DENTRY_IN_BLOCK;
kunmap(dentry_page);
f2fs_put_page(dentry_page, 1);
dentry_page = NULL;
}
success:
if (dentry_page && !IS_ERR(dentry_page)) {
kunmap(dentry_page);
f2fs_put_page(dentry_page, 1);
}
return 0;
}
const struct file_operations f2fs_dir_operations = {
.llseek = generic_file_llseek,
.read = generic_read_dir,
.readdir = f2fs_readdir,
.fsync = f2fs_sync_file,
.unlocked_ioctl = f2fs_ioctl,
};