![Tao Ma](/assets/img/avatar_default.png)
Let readpage and readpages handle the case when we want to read an inlined file. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
528 lines
12 KiB
C
528 lines
12 KiB
C
/*
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* Copyright (c) 2012 Taobao.
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* Written by Tao Ma <boyu.mt@taobao.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of version 2.1 of the GNU Lesser General Public License
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include "ext4_jbd2.h"
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#include "ext4.h"
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#include "xattr.h"
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#define EXT4_XATTR_SYSTEM_DATA "data"
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#define EXT4_MIN_INLINE_DATA_SIZE ((sizeof(__le32) * EXT4_N_BLOCKS))
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int ext4_get_inline_size(struct inode *inode)
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{
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if (EXT4_I(inode)->i_inline_off)
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return EXT4_I(inode)->i_inline_size;
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return 0;
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}
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static int get_max_inline_xattr_value_size(struct inode *inode,
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struct ext4_iloc *iloc)
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{
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struct ext4_xattr_ibody_header *header;
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struct ext4_xattr_entry *entry;
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struct ext4_inode *raw_inode;
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int free, min_offs;
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min_offs = EXT4_SB(inode->i_sb)->s_inode_size -
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EXT4_GOOD_OLD_INODE_SIZE -
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EXT4_I(inode)->i_extra_isize -
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sizeof(struct ext4_xattr_ibody_header);
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/*
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* We need to subtract another sizeof(__u32) since an in-inode xattr
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* needs an empty 4 bytes to indicate the gap between the xattr entry
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* and the name/value pair.
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*/
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if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR))
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return EXT4_XATTR_SIZE(min_offs -
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EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA)) -
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EXT4_XATTR_ROUND - sizeof(__u32));
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raw_inode = ext4_raw_inode(iloc);
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header = IHDR(inode, raw_inode);
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entry = IFIRST(header);
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/* Compute min_offs. */
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for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
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if (!entry->e_value_block && entry->e_value_size) {
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size_t offs = le16_to_cpu(entry->e_value_offs);
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if (offs < min_offs)
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min_offs = offs;
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}
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}
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free = min_offs -
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((void *)entry - (void *)IFIRST(header)) - sizeof(__u32);
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if (EXT4_I(inode)->i_inline_off) {
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entry = (struct ext4_xattr_entry *)
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((void *)raw_inode + EXT4_I(inode)->i_inline_off);
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free += le32_to_cpu(entry->e_value_size);
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goto out;
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}
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free -= EXT4_XATTR_LEN(strlen(EXT4_XATTR_SYSTEM_DATA));
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if (free > EXT4_XATTR_ROUND)
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free = EXT4_XATTR_SIZE(free - EXT4_XATTR_ROUND);
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else
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free = 0;
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out:
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return free;
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}
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/*
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* Get the maximum size we now can store in an inode.
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* If we can't find the space for a xattr entry, don't use the space
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* of the extents since we have no space to indicate the inline data.
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*/
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int ext4_get_max_inline_size(struct inode *inode)
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{
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int error, max_inline_size;
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struct ext4_iloc iloc;
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if (EXT4_I(inode)->i_extra_isize == 0)
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return 0;
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error = ext4_get_inode_loc(inode, &iloc);
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if (error) {
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ext4_error_inode(inode, __func__, __LINE__, 0,
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"can't get inode location %lu",
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inode->i_ino);
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return 0;
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}
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down_read(&EXT4_I(inode)->xattr_sem);
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max_inline_size = get_max_inline_xattr_value_size(inode, &iloc);
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up_read(&EXT4_I(inode)->xattr_sem);
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brelse(iloc.bh);
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if (!max_inline_size)
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return 0;
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return max_inline_size + EXT4_MIN_INLINE_DATA_SIZE;
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}
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int ext4_has_inline_data(struct inode *inode)
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{
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return ext4_test_inode_flag(inode, EXT4_INODE_INLINE_DATA) &&
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EXT4_I(inode)->i_inline_off;
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}
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/*
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* this function does not take xattr_sem, which is OK because it is
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* currently only used in a code path coming form ext4_iget, before
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* the new inode has been unlocked
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*/
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int ext4_find_inline_data_nolock(struct inode *inode)
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{
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struct ext4_xattr_ibody_find is = {
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.s = { .not_found = -ENODATA, },
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};
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struct ext4_xattr_info i = {
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.name_index = EXT4_XATTR_INDEX_SYSTEM,
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.name = EXT4_XATTR_SYSTEM_DATA,
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};
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int error;
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if (EXT4_I(inode)->i_extra_isize == 0)
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return 0;
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error = ext4_get_inode_loc(inode, &is.iloc);
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if (error)
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return error;
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error = ext4_xattr_ibody_find(inode, &i, &is);
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if (error)
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goto out;
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if (!is.s.not_found) {
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EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
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(void *)ext4_raw_inode(&is.iloc));
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EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
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le32_to_cpu(is.s.here->e_value_size);
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ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
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}
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out:
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brelse(is.iloc.bh);
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return error;
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}
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static int ext4_read_inline_data(struct inode *inode, void *buffer,
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unsigned int len,
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struct ext4_iloc *iloc)
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{
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struct ext4_xattr_entry *entry;
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struct ext4_xattr_ibody_header *header;
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int cp_len = 0;
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struct ext4_inode *raw_inode;
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if (!len)
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return 0;
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BUG_ON(len > EXT4_I(inode)->i_inline_size);
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cp_len = len < EXT4_MIN_INLINE_DATA_SIZE ?
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len : EXT4_MIN_INLINE_DATA_SIZE;
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raw_inode = ext4_raw_inode(iloc);
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memcpy(buffer, (void *)(raw_inode->i_block), cp_len);
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len -= cp_len;
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buffer += cp_len;
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if (!len)
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goto out;
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header = IHDR(inode, raw_inode);
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entry = (struct ext4_xattr_entry *)((void *)raw_inode +
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EXT4_I(inode)->i_inline_off);
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len = min_t(unsigned int, len,
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(unsigned int)le32_to_cpu(entry->e_value_size));
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memcpy(buffer,
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(void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs), len);
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cp_len += len;
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out:
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return cp_len;
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}
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/*
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* write the buffer to the inline inode.
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* If 'create' is set, we don't need to do the extra copy in the xattr
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* value since it is already handled by ext4_xattr_ibody_set. That saves
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* us one memcpy.
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*/
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void ext4_write_inline_data(struct inode *inode, struct ext4_iloc *iloc,
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void *buffer, loff_t pos, unsigned int len)
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{
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struct ext4_xattr_entry *entry;
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struct ext4_xattr_ibody_header *header;
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struct ext4_inode *raw_inode;
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int cp_len = 0;
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BUG_ON(!EXT4_I(inode)->i_inline_off);
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BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);
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raw_inode = ext4_raw_inode(iloc);
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buffer += pos;
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if (pos < EXT4_MIN_INLINE_DATA_SIZE) {
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cp_len = pos + len > EXT4_MIN_INLINE_DATA_SIZE ?
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EXT4_MIN_INLINE_DATA_SIZE - pos : len;
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memcpy((void *)raw_inode->i_block + pos, buffer, cp_len);
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len -= cp_len;
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buffer += cp_len;
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pos += cp_len;
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}
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if (!len)
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return;
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pos -= EXT4_MIN_INLINE_DATA_SIZE;
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header = IHDR(inode, raw_inode);
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entry = (struct ext4_xattr_entry *)((void *)raw_inode +
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EXT4_I(inode)->i_inline_off);
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memcpy((void *)IFIRST(header) + le16_to_cpu(entry->e_value_offs) + pos,
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buffer, len);
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}
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static int ext4_create_inline_data(handle_t *handle,
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struct inode *inode, unsigned len)
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{
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int error;
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void *value = NULL;
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struct ext4_xattr_ibody_find is = {
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.s = { .not_found = -ENODATA, },
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};
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struct ext4_xattr_info i = {
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.name_index = EXT4_XATTR_INDEX_SYSTEM,
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.name = EXT4_XATTR_SYSTEM_DATA,
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};
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error = ext4_get_inode_loc(inode, &is.iloc);
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if (error)
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return error;
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error = ext4_journal_get_write_access(handle, is.iloc.bh);
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if (error)
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goto out;
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if (len > EXT4_MIN_INLINE_DATA_SIZE) {
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value = (void *)empty_zero_page;
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len -= EXT4_MIN_INLINE_DATA_SIZE;
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} else {
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value = "";
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len = 0;
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}
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/* Insert the the xttr entry. */
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i.value = value;
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i.value_len = len;
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error = ext4_xattr_ibody_find(inode, &i, &is);
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if (error)
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goto out;
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BUG_ON(!is.s.not_found);
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error = ext4_xattr_ibody_set(handle, inode, &i, &is);
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if (error) {
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if (error == -ENOSPC)
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ext4_clear_inode_state(inode,
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EXT4_STATE_MAY_INLINE_DATA);
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goto out;
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}
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memset((void *)ext4_raw_inode(&is.iloc)->i_block,
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0, EXT4_MIN_INLINE_DATA_SIZE);
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EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
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(void *)ext4_raw_inode(&is.iloc));
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EXT4_I(inode)->i_inline_size = len + EXT4_MIN_INLINE_DATA_SIZE;
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ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
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ext4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA);
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get_bh(is.iloc.bh);
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error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
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out:
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brelse(is.iloc.bh);
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return error;
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}
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static int ext4_update_inline_data(handle_t *handle, struct inode *inode,
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unsigned int len)
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{
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int error;
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void *value = NULL;
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struct ext4_xattr_ibody_find is = {
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.s = { .not_found = -ENODATA, },
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};
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struct ext4_xattr_info i = {
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.name_index = EXT4_XATTR_INDEX_SYSTEM,
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.name = EXT4_XATTR_SYSTEM_DATA,
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};
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/* If the old space is ok, write the data directly. */
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if (len <= EXT4_I(inode)->i_inline_size)
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return 0;
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error = ext4_get_inode_loc(inode, &is.iloc);
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if (error)
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return error;
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error = ext4_xattr_ibody_find(inode, &i, &is);
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if (error)
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goto out;
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BUG_ON(is.s.not_found);
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len -= EXT4_MIN_INLINE_DATA_SIZE;
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value = kzalloc(len, GFP_NOFS);
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if (!value)
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goto out;
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error = ext4_xattr_ibody_get(inode, i.name_index, i.name,
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value, len);
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if (error == -ENODATA)
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goto out;
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error = ext4_journal_get_write_access(handle, is.iloc.bh);
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if (error)
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goto out;
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/* Update the xttr entry. */
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i.value = value;
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i.value_len = len;
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error = ext4_xattr_ibody_set(handle, inode, &i, &is);
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if (error)
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goto out;
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EXT4_I(inode)->i_inline_off = (u16)((void *)is.s.here -
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(void *)ext4_raw_inode(&is.iloc));
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EXT4_I(inode)->i_inline_size = EXT4_MIN_INLINE_DATA_SIZE +
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le32_to_cpu(is.s.here->e_value_size);
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ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
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get_bh(is.iloc.bh);
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error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
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out:
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kfree(value);
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brelse(is.iloc.bh);
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return error;
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}
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int ext4_prepare_inline_data(handle_t *handle, struct inode *inode,
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unsigned int len)
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{
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int ret, size;
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struct ext4_inode_info *ei = EXT4_I(inode);
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if (!ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA))
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return -ENOSPC;
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size = ext4_get_max_inline_size(inode);
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if (size < len)
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return -ENOSPC;
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down_write(&EXT4_I(inode)->xattr_sem);
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if (ei->i_inline_off)
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ret = ext4_update_inline_data(handle, inode, len);
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else
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ret = ext4_create_inline_data(handle, inode, len);
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up_write(&EXT4_I(inode)->xattr_sem);
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return ret;
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}
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static int ext4_destroy_inline_data_nolock(handle_t *handle,
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struct inode *inode)
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{
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struct ext4_inode_info *ei = EXT4_I(inode);
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struct ext4_xattr_ibody_find is = {
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.s = { .not_found = 0, },
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};
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struct ext4_xattr_info i = {
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.name_index = EXT4_XATTR_INDEX_SYSTEM,
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.name = EXT4_XATTR_SYSTEM_DATA,
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.value = NULL,
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.value_len = 0,
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};
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int error;
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if (!ei->i_inline_off)
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return 0;
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error = ext4_get_inode_loc(inode, &is.iloc);
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if (error)
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return error;
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error = ext4_xattr_ibody_find(inode, &i, &is);
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if (error)
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goto out;
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error = ext4_journal_get_write_access(handle, is.iloc.bh);
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if (error)
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goto out;
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error = ext4_xattr_ibody_set(handle, inode, &i, &is);
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if (error)
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goto out;
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memset((void *)ext4_raw_inode(&is.iloc)->i_block,
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0, EXT4_MIN_INLINE_DATA_SIZE);
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if (EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
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EXT4_FEATURE_INCOMPAT_EXTENTS)) {
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if (S_ISDIR(inode->i_mode) ||
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S_ISREG(inode->i_mode) || S_ISLNK(inode->i_mode)) {
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ext4_set_inode_flag(inode, EXT4_INODE_EXTENTS);
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ext4_ext_tree_init(handle, inode);
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}
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}
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ext4_clear_inode_flag(inode, EXT4_INODE_INLINE_DATA);
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get_bh(is.iloc.bh);
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error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
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EXT4_I(inode)->i_inline_off = 0;
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EXT4_I(inode)->i_inline_size = 0;
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ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
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out:
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brelse(is.iloc.bh);
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if (error == -ENODATA)
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error = 0;
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return error;
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}
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static int ext4_read_inline_page(struct inode *inode, struct page *page)
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{
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void *kaddr;
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int ret = 0;
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size_t len;
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struct ext4_iloc iloc;
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BUG_ON(!PageLocked(page));
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BUG_ON(!ext4_has_inline_data(inode));
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BUG_ON(page->index);
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if (!EXT4_I(inode)->i_inline_off) {
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ext4_warning(inode->i_sb, "inode %lu doesn't have inline data.",
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inode->i_ino);
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goto out;
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}
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ret = ext4_get_inode_loc(inode, &iloc);
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if (ret)
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goto out;
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len = min_t(size_t, ext4_get_inline_size(inode), i_size_read(inode));
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kaddr = kmap_atomic(page);
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ret = ext4_read_inline_data(inode, kaddr, len, &iloc);
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flush_dcache_page(page);
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kunmap_atomic(kaddr);
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zero_user_segment(page, len, PAGE_CACHE_SIZE);
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SetPageUptodate(page);
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brelse(iloc.bh);
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out:
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return ret;
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}
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int ext4_readpage_inline(struct inode *inode, struct page *page)
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{
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int ret = 0;
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down_read(&EXT4_I(inode)->xattr_sem);
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if (!ext4_has_inline_data(inode)) {
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up_read(&EXT4_I(inode)->xattr_sem);
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return -EAGAIN;
|
|
}
|
|
|
|
/*
|
|
* Current inline data can only exist in the 1st page,
|
|
* So for all the other pages, just set them uptodate.
|
|
*/
|
|
if (!page->index)
|
|
ret = ext4_read_inline_page(inode, page);
|
|
else if (!PageUptodate(page)) {
|
|
zero_user_segment(page, 0, PAGE_CACHE_SIZE);
|
|
SetPageUptodate(page);
|
|
}
|
|
|
|
up_read(&EXT4_I(inode)->xattr_sem);
|
|
|
|
unlock_page(page);
|
|
return ret >= 0 ? 0 : ret;
|
|
}
|
|
|
|
int ext4_destroy_inline_data(handle_t *handle, struct inode *inode)
|
|
{
|
|
int ret;
|
|
|
|
down_write(&EXT4_I(inode)->xattr_sem);
|
|
ret = ext4_destroy_inline_data_nolock(handle, inode);
|
|
up_write(&EXT4_I(inode)->xattr_sem);
|
|
|
|
return ret;
|
|
}
|