![Christoph Hellwig](/assets/img/avatar_default.png)
generic_file_aio_write already calls into ->fsync to handle O_SYNC/O_DSYNC. Remove the duplicate call to ubifs_sync_wbufs_by_inode which is already covered by ubifs_fsync. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
1586 lines
44 KiB
C
1586 lines
44 KiB
C
/*
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* This file is part of UBIFS.
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*
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* Copyright (C) 2006-2008 Nokia Corporation.
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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 the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Authors: Artem Bityutskiy (Битюцкий Артём)
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* Adrian Hunter
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*/
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/*
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* This file implements VFS file and inode operations for regular files, device
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* nodes and symlinks as well as address space operations.
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*
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* UBIFS uses 2 page flags: @PG_private and @PG_checked. @PG_private is set if
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* the page is dirty and is used for optimization purposes - dirty pages are
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* not budgeted so the flag shows that 'ubifs_write_end()' should not release
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* the budget for this page. The @PG_checked flag is set if full budgeting is
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* required for the page e.g., when it corresponds to a file hole or it is
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* beyond the file size. The budgeting is done in 'ubifs_write_begin()', because
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* it is OK to fail in this function, and the budget is released in
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* 'ubifs_write_end()'. So the @PG_private and @PG_checked flags carry
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* information about how the page was budgeted, to make it possible to release
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* the budget properly.
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*
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* A thing to keep in mind: inode @i_mutex is locked in most VFS operations we
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* implement. However, this is not true for 'ubifs_writepage()', which may be
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* called with @i_mutex unlocked. For example, when pdflush is doing background
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* write-back, it calls 'ubifs_writepage()' with unlocked @i_mutex. At "normal"
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* work-paths the @i_mutex is locked in 'ubifs_writepage()', e.g. in the
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* "sys_write -> alloc_pages -> direct reclaim path". So, in 'ubifs_writepage()'
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* we are only guaranteed that the page is locked.
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*
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* Similarly, @i_mutex is not always locked in 'ubifs_readpage()', e.g., the
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* read-ahead path does not lock it ("sys_read -> generic_file_aio_read ->
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* ondemand_readahead -> readpage"). In case of readahead, @I_LOCK flag is not
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* set as well. However, UBIFS disables readahead.
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*/
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#include "ubifs.h"
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#include <linux/mount.h>
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#include <linux/namei.h>
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static int read_block(struct inode *inode, void *addr, unsigned int block,
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struct ubifs_data_node *dn)
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{
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struct ubifs_info *c = inode->i_sb->s_fs_info;
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int err, len, out_len;
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union ubifs_key key;
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unsigned int dlen;
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data_key_init(c, &key, inode->i_ino, block);
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err = ubifs_tnc_lookup(c, &key, dn);
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if (err) {
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if (err == -ENOENT)
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/* Not found, so it must be a hole */
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memset(addr, 0, UBIFS_BLOCK_SIZE);
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return err;
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}
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ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
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ubifs_inode(inode)->creat_sqnum);
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len = le32_to_cpu(dn->size);
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if (len <= 0 || len > UBIFS_BLOCK_SIZE)
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goto dump;
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dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
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out_len = UBIFS_BLOCK_SIZE;
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err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
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le16_to_cpu(dn->compr_type));
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if (err || len != out_len)
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goto dump;
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/*
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* Data length can be less than a full block, even for blocks that are
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* not the last in the file (e.g., as a result of making a hole and
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* appending data). Ensure that the remainder is zeroed out.
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*/
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if (len < UBIFS_BLOCK_SIZE)
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memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
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return 0;
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dump:
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ubifs_err("bad data node (block %u, inode %lu)",
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block, inode->i_ino);
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dbg_dump_node(c, dn);
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return -EINVAL;
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}
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static int do_readpage(struct page *page)
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{
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void *addr;
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int err = 0, i;
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unsigned int block, beyond;
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struct ubifs_data_node *dn;
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struct inode *inode = page->mapping->host;
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loff_t i_size = i_size_read(inode);
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dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
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inode->i_ino, page->index, i_size, page->flags);
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ubifs_assert(!PageChecked(page));
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ubifs_assert(!PagePrivate(page));
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addr = kmap(page);
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block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
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beyond = (i_size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
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if (block >= beyond) {
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/* Reading beyond inode */
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SetPageChecked(page);
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memset(addr, 0, PAGE_CACHE_SIZE);
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goto out;
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}
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dn = kmalloc(UBIFS_MAX_DATA_NODE_SZ, GFP_NOFS);
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if (!dn) {
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err = -ENOMEM;
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goto error;
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}
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i = 0;
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while (1) {
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int ret;
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if (block >= beyond) {
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/* Reading beyond inode */
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err = -ENOENT;
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memset(addr, 0, UBIFS_BLOCK_SIZE);
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} else {
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ret = read_block(inode, addr, block, dn);
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if (ret) {
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err = ret;
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if (err != -ENOENT)
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break;
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} else if (block + 1 == beyond) {
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int dlen = le32_to_cpu(dn->size);
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int ilen = i_size & (UBIFS_BLOCK_SIZE - 1);
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if (ilen && ilen < dlen)
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memset(addr + ilen, 0, dlen - ilen);
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}
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}
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if (++i >= UBIFS_BLOCKS_PER_PAGE)
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break;
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block += 1;
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addr += UBIFS_BLOCK_SIZE;
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}
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if (err) {
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if (err == -ENOENT) {
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/* Not found, so it must be a hole */
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SetPageChecked(page);
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dbg_gen("hole");
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goto out_free;
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}
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ubifs_err("cannot read page %lu of inode %lu, error %d",
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page->index, inode->i_ino, err);
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goto error;
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}
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out_free:
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kfree(dn);
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out:
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SetPageUptodate(page);
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ClearPageError(page);
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flush_dcache_page(page);
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kunmap(page);
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return 0;
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error:
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kfree(dn);
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ClearPageUptodate(page);
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SetPageError(page);
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flush_dcache_page(page);
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kunmap(page);
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return err;
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}
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/**
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* release_new_page_budget - release budget of a new page.
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* @c: UBIFS file-system description object
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*
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* This is a helper function which releases budget corresponding to the budget
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* of one new page of data.
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*/
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static void release_new_page_budget(struct ubifs_info *c)
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{
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struct ubifs_budget_req req = { .recalculate = 1, .new_page = 1 };
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ubifs_release_budget(c, &req);
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}
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/**
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* release_existing_page_budget - release budget of an existing page.
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* @c: UBIFS file-system description object
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*
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* This is a helper function which releases budget corresponding to the budget
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* of changing one one page of data which already exists on the flash media.
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*/
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static void release_existing_page_budget(struct ubifs_info *c)
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{
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struct ubifs_budget_req req = { .dd_growth = c->page_budget};
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ubifs_release_budget(c, &req);
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}
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static int write_begin_slow(struct address_space *mapping,
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loff_t pos, unsigned len, struct page **pagep,
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unsigned flags)
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{
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struct inode *inode = mapping->host;
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struct ubifs_info *c = inode->i_sb->s_fs_info;
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pgoff_t index = pos >> PAGE_CACHE_SHIFT;
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struct ubifs_budget_req req = { .new_page = 1 };
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int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
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struct page *page;
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dbg_gen("ino %lu, pos %llu, len %u, i_size %lld",
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inode->i_ino, pos, len, inode->i_size);
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/*
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* At the slow path we have to budget before locking the page, because
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* budgeting may force write-back, which would wait on locked pages and
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* deadlock if we had the page locked. At this point we do not know
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* anything about the page, so assume that this is a new page which is
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* written to a hole. This corresponds to largest budget. Later the
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* budget will be amended if this is not true.
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*/
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if (appending)
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/* We are appending data, budget for inode change */
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req.dirtied_ino = 1;
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err = ubifs_budget_space(c, &req);
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if (unlikely(err))
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return err;
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page = grab_cache_page_write_begin(mapping, index, flags);
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if (unlikely(!page)) {
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ubifs_release_budget(c, &req);
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return -ENOMEM;
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}
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if (!PageUptodate(page)) {
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if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE)
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SetPageChecked(page);
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else {
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err = do_readpage(page);
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if (err) {
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unlock_page(page);
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page_cache_release(page);
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return err;
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}
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}
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SetPageUptodate(page);
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ClearPageError(page);
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}
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if (PagePrivate(page))
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/*
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* The page is dirty, which means it was budgeted twice:
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* o first time the budget was allocated by the task which
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* made the page dirty and set the PG_private flag;
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* o and then we budgeted for it for the second time at the
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* very beginning of this function.
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*
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* So what we have to do is to release the page budget we
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* allocated.
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*/
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release_new_page_budget(c);
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else if (!PageChecked(page))
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/*
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* We are changing a page which already exists on the media.
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* This means that changing the page does not make the amount
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* of indexing information larger, and this part of the budget
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* which we have already acquired may be released.
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*/
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ubifs_convert_page_budget(c);
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if (appending) {
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struct ubifs_inode *ui = ubifs_inode(inode);
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/*
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* 'ubifs_write_end()' is optimized from the fast-path part of
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* 'ubifs_write_begin()' and expects the @ui_mutex to be locked
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* if data is appended.
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*/
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mutex_lock(&ui->ui_mutex);
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if (ui->dirty)
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/*
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* The inode is dirty already, so we may free the
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* budget we allocated.
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*/
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ubifs_release_dirty_inode_budget(c, ui);
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}
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*pagep = page;
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return 0;
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}
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/**
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* allocate_budget - allocate budget for 'ubifs_write_begin()'.
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* @c: UBIFS file-system description object
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* @page: page to allocate budget for
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* @ui: UBIFS inode object the page belongs to
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* @appending: non-zero if the page is appended
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*
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* This is a helper function for 'ubifs_write_begin()' which allocates budget
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* for the operation. The budget is allocated differently depending on whether
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* this is appending, whether the page is dirty or not, and so on. This
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* function leaves the @ui->ui_mutex locked in case of appending. Returns zero
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* in case of success and %-ENOSPC in case of failure.
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*/
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static int allocate_budget(struct ubifs_info *c, struct page *page,
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struct ubifs_inode *ui, int appending)
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{
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struct ubifs_budget_req req = { .fast = 1 };
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if (PagePrivate(page)) {
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if (!appending)
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/*
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* The page is dirty and we are not appending, which
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* means no budget is needed at all.
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*/
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return 0;
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mutex_lock(&ui->ui_mutex);
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if (ui->dirty)
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/*
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* The page is dirty and we are appending, so the inode
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* has to be marked as dirty. However, it is already
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* dirty, so we do not need any budget. We may return,
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* but @ui->ui_mutex hast to be left locked because we
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* should prevent write-back from flushing the inode
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* and freeing the budget. The lock will be released in
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* 'ubifs_write_end()'.
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*/
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return 0;
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/*
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* The page is dirty, we are appending, the inode is clean, so
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* we need to budget the inode change.
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*/
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req.dirtied_ino = 1;
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} else {
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if (PageChecked(page))
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/*
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* The page corresponds to a hole and does not
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* exist on the media. So changing it makes
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* make the amount of indexing information
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* larger, and we have to budget for a new
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* page.
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*/
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req.new_page = 1;
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else
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/*
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* Not a hole, the change will not add any new
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* indexing information, budget for page
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* change.
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*/
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req.dirtied_page = 1;
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if (appending) {
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mutex_lock(&ui->ui_mutex);
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if (!ui->dirty)
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/*
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* The inode is clean but we will have to mark
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* it as dirty because we are appending. This
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* needs a budget.
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*/
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req.dirtied_ino = 1;
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}
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}
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return ubifs_budget_space(c, &req);
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}
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/*
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* This function is called when a page of data is going to be written. Since
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* the page of data will not necessarily go to the flash straight away, UBIFS
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* has to reserve space on the media for it, which is done by means of
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* budgeting.
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*
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* This is the hot-path of the file-system and we are trying to optimize it as
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* much as possible. For this reasons it is split on 2 parts - slow and fast.
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*
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* There many budgeting cases:
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* o a new page is appended - we have to budget for a new page and for
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* changing the inode; however, if the inode is already dirty, there is
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* no need to budget for it;
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* o an existing clean page is changed - we have budget for it; if the page
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* does not exist on the media (a hole), we have to budget for a new
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* page; otherwise, we may budget for changing an existing page; the
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* difference between these cases is that changing an existing page does
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* not introduce anything new to the FS indexing information, so it does
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* not grow, and smaller budget is acquired in this case;
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* o an existing dirty page is changed - no need to budget at all, because
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* the page budget has been acquired by earlier, when the page has been
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* marked dirty.
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*
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* UBIFS budgeting sub-system may force write-back if it thinks there is no
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* space to reserve. This imposes some locking restrictions and makes it
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* impossible to take into account the above cases, and makes it impossible to
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* optimize budgeting.
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*
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* The solution for this is that the fast path of 'ubifs_write_begin()' assumes
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* there is a plenty of flash space and the budget will be acquired quickly,
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* without forcing write-back. The slow path does not make this assumption.
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*/
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static int ubifs_write_begin(struct file *file, struct address_space *mapping,
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loff_t pos, unsigned len, unsigned flags,
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struct page **pagep, void **fsdata)
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{
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struct inode *inode = mapping->host;
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struct ubifs_info *c = inode->i_sb->s_fs_info;
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struct ubifs_inode *ui = ubifs_inode(inode);
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pgoff_t index = pos >> PAGE_CACHE_SHIFT;
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int uninitialized_var(err), appending = !!(pos + len > inode->i_size);
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int skipped_read = 0;
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struct page *page;
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ubifs_assert(ubifs_inode(inode)->ui_size == inode->i_size);
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if (unlikely(c->ro_media))
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return -EROFS;
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|
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/* Try out the fast-path part first */
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page = grab_cache_page_write_begin(mapping, index, flags);
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if (unlikely(!page))
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return -ENOMEM;
|
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|
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if (!PageUptodate(page)) {
|
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/* The page is not loaded from the flash */
|
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if (!(pos & ~PAGE_CACHE_MASK) && len == PAGE_CACHE_SIZE) {
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/*
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* We change whole page so no need to load it. But we
|
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* have to set the @PG_checked flag to make the further
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* code know that the page is new. This might be not
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* true, but it is better to budget more than to read
|
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* the page from the media.
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*/
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SetPageChecked(page);
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skipped_read = 1;
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} else {
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err = do_readpage(page);
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if (err) {
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unlock_page(page);
|
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page_cache_release(page);
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return err;
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}
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}
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SetPageUptodate(page);
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ClearPageError(page);
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}
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err = allocate_budget(c, page, ui, appending);
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if (unlikely(err)) {
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ubifs_assert(err == -ENOSPC);
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/*
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* If we skipped reading the page because we were going to
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* write all of it, then it is not up to date.
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*/
|
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if (skipped_read) {
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ClearPageChecked(page);
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ClearPageUptodate(page);
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}
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/*
|
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* Budgeting failed which means it would have to force
|
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* write-back but didn't, because we set the @fast flag in the
|
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* request. Write-back cannot be done now, while we have the
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* page locked, because it would deadlock. Unlock and free
|
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* everything and fall-back to slow-path.
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*/
|
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if (appending) {
|
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ubifs_assert(mutex_is_locked(&ui->ui_mutex));
|
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mutex_unlock(&ui->ui_mutex);
|
|
}
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
|
|
return write_begin_slow(mapping, pos, len, pagep, flags);
|
|
}
|
|
|
|
/*
|
|
* Whee, we acquired budgeting quickly - without involving
|
|
* garbage-collection, committing or forcing write-back. We return
|
|
* with @ui->ui_mutex locked if we are appending pages, and unlocked
|
|
* otherwise. This is an optimization (slightly hacky though).
|
|
*/
|
|
*pagep = page;
|
|
return 0;
|
|
|
|
}
|
|
|
|
/**
|
|
* cancel_budget - cancel budget.
|
|
* @c: UBIFS file-system description object
|
|
* @page: page to cancel budget for
|
|
* @ui: UBIFS inode object the page belongs to
|
|
* @appending: non-zero if the page is appended
|
|
*
|
|
* This is a helper function for a page write operation. It unlocks the
|
|
* @ui->ui_mutex in case of appending.
|
|
*/
|
|
static void cancel_budget(struct ubifs_info *c, struct page *page,
|
|
struct ubifs_inode *ui, int appending)
|
|
{
|
|
if (appending) {
|
|
if (!ui->dirty)
|
|
ubifs_release_dirty_inode_budget(c, ui);
|
|
mutex_unlock(&ui->ui_mutex);
|
|
}
|
|
if (!PagePrivate(page)) {
|
|
if (PageChecked(page))
|
|
release_new_page_budget(c);
|
|
else
|
|
release_existing_page_budget(c);
|
|
}
|
|
}
|
|
|
|
static int ubifs_write_end(struct file *file, struct address_space *mapping,
|
|
loff_t pos, unsigned len, unsigned copied,
|
|
struct page *page, void *fsdata)
|
|
{
|
|
struct inode *inode = mapping->host;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
loff_t end_pos = pos + len;
|
|
int appending = !!(end_pos > inode->i_size);
|
|
|
|
dbg_gen("ino %lu, pos %llu, pg %lu, len %u, copied %d, i_size %lld",
|
|
inode->i_ino, pos, page->index, len, copied, inode->i_size);
|
|
|
|
if (unlikely(copied < len && len == PAGE_CACHE_SIZE)) {
|
|
/*
|
|
* VFS copied less data to the page that it intended and
|
|
* declared in its '->write_begin()' call via the @len
|
|
* argument. If the page was not up-to-date, and @len was
|
|
* @PAGE_CACHE_SIZE, the 'ubifs_write_begin()' function did
|
|
* not load it from the media (for optimization reasons). This
|
|
* means that part of the page contains garbage. So read the
|
|
* page now.
|
|
*/
|
|
dbg_gen("copied %d instead of %d, read page and repeat",
|
|
copied, len);
|
|
cancel_budget(c, page, ui, appending);
|
|
|
|
/*
|
|
* Return 0 to force VFS to repeat the whole operation, or the
|
|
* error code if 'do_readpage()' fails.
|
|
*/
|
|
copied = do_readpage(page);
|
|
goto out;
|
|
}
|
|
|
|
if (!PagePrivate(page)) {
|
|
SetPagePrivate(page);
|
|
atomic_long_inc(&c->dirty_pg_cnt);
|
|
__set_page_dirty_nobuffers(page);
|
|
}
|
|
|
|
if (appending) {
|
|
i_size_write(inode, end_pos);
|
|
ui->ui_size = end_pos;
|
|
/*
|
|
* Note, we do not set @I_DIRTY_PAGES (which means that the
|
|
* inode has dirty pages), this has been done in
|
|
* '__set_page_dirty_nobuffers()'.
|
|
*/
|
|
__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
|
|
ubifs_assert(mutex_is_locked(&ui->ui_mutex));
|
|
mutex_unlock(&ui->ui_mutex);
|
|
}
|
|
|
|
out:
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
return copied;
|
|
}
|
|
|
|
/**
|
|
* populate_page - copy data nodes into a page for bulk-read.
|
|
* @c: UBIFS file-system description object
|
|
* @page: page
|
|
* @bu: bulk-read information
|
|
* @n: next zbranch slot
|
|
*
|
|
* This function returns %0 on success and a negative error code on failure.
|
|
*/
|
|
static int populate_page(struct ubifs_info *c, struct page *page,
|
|
struct bu_info *bu, int *n)
|
|
{
|
|
int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 0, read = 0;
|
|
struct inode *inode = page->mapping->host;
|
|
loff_t i_size = i_size_read(inode);
|
|
unsigned int page_block;
|
|
void *addr, *zaddr;
|
|
pgoff_t end_index;
|
|
|
|
dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
|
|
inode->i_ino, page->index, i_size, page->flags);
|
|
|
|
addr = zaddr = kmap(page);
|
|
|
|
end_index = (i_size - 1) >> PAGE_CACHE_SHIFT;
|
|
if (!i_size || page->index > end_index) {
|
|
hole = 1;
|
|
memset(addr, 0, PAGE_CACHE_SIZE);
|
|
goto out_hole;
|
|
}
|
|
|
|
page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
|
|
while (1) {
|
|
int err, len, out_len, dlen;
|
|
|
|
if (nn >= bu->cnt) {
|
|
hole = 1;
|
|
memset(addr, 0, UBIFS_BLOCK_SIZE);
|
|
} else if (key_block(c, &bu->zbranch[nn].key) == page_block) {
|
|
struct ubifs_data_node *dn;
|
|
|
|
dn = bu->buf + (bu->zbranch[nn].offs - offs);
|
|
|
|
ubifs_assert(le64_to_cpu(dn->ch.sqnum) >
|
|
ubifs_inode(inode)->creat_sqnum);
|
|
|
|
len = le32_to_cpu(dn->size);
|
|
if (len <= 0 || len > UBIFS_BLOCK_SIZE)
|
|
goto out_err;
|
|
|
|
dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
|
|
out_len = UBIFS_BLOCK_SIZE;
|
|
err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
|
|
le16_to_cpu(dn->compr_type));
|
|
if (err || len != out_len)
|
|
goto out_err;
|
|
|
|
if (len < UBIFS_BLOCK_SIZE)
|
|
memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
|
|
|
|
nn += 1;
|
|
read = (i << UBIFS_BLOCK_SHIFT) + len;
|
|
} else if (key_block(c, &bu->zbranch[nn].key) < page_block) {
|
|
nn += 1;
|
|
continue;
|
|
} else {
|
|
hole = 1;
|
|
memset(addr, 0, UBIFS_BLOCK_SIZE);
|
|
}
|
|
if (++i >= UBIFS_BLOCKS_PER_PAGE)
|
|
break;
|
|
addr += UBIFS_BLOCK_SIZE;
|
|
page_block += 1;
|
|
}
|
|
|
|
if (end_index == page->index) {
|
|
int len = i_size & (PAGE_CACHE_SIZE - 1);
|
|
|
|
if (len && len < read)
|
|
memset(zaddr + len, 0, read - len);
|
|
}
|
|
|
|
out_hole:
|
|
if (hole) {
|
|
SetPageChecked(page);
|
|
dbg_gen("hole");
|
|
}
|
|
|
|
SetPageUptodate(page);
|
|
ClearPageError(page);
|
|
flush_dcache_page(page);
|
|
kunmap(page);
|
|
*n = nn;
|
|
return 0;
|
|
|
|
out_err:
|
|
ClearPageUptodate(page);
|
|
SetPageError(page);
|
|
flush_dcache_page(page);
|
|
kunmap(page);
|
|
ubifs_err("bad data node (block %u, inode %lu)",
|
|
page_block, inode->i_ino);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/**
|
|
* ubifs_do_bulk_read - do bulk-read.
|
|
* @c: UBIFS file-system description object
|
|
* @bu: bulk-read information
|
|
* @page1: first page to read
|
|
*
|
|
* This function returns %1 if the bulk-read is done, otherwise %0 is returned.
|
|
*/
|
|
static int ubifs_do_bulk_read(struct ubifs_info *c, struct bu_info *bu,
|
|
struct page *page1)
|
|
{
|
|
pgoff_t offset = page1->index, end_index;
|
|
struct address_space *mapping = page1->mapping;
|
|
struct inode *inode = mapping->host;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
int err, page_idx, page_cnt, ret = 0, n = 0;
|
|
int allocate = bu->buf ? 0 : 1;
|
|
loff_t isize;
|
|
|
|
err = ubifs_tnc_get_bu_keys(c, bu);
|
|
if (err)
|
|
goto out_warn;
|
|
|
|
if (bu->eof) {
|
|
/* Turn off bulk-read at the end of the file */
|
|
ui->read_in_a_row = 1;
|
|
ui->bulk_read = 0;
|
|
}
|
|
|
|
page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT;
|
|
if (!page_cnt) {
|
|
/*
|
|
* This happens when there are multiple blocks per page and the
|
|
* blocks for the first page we are looking for, are not
|
|
* together. If all the pages were like this, bulk-read would
|
|
* reduce performance, so we turn it off for a while.
|
|
*/
|
|
goto out_bu_off;
|
|
}
|
|
|
|
if (bu->cnt) {
|
|
if (allocate) {
|
|
/*
|
|
* Allocate bulk-read buffer depending on how many data
|
|
* nodes we are going to read.
|
|
*/
|
|
bu->buf_len = bu->zbranch[bu->cnt - 1].offs +
|
|
bu->zbranch[bu->cnt - 1].len -
|
|
bu->zbranch[0].offs;
|
|
ubifs_assert(bu->buf_len > 0);
|
|
ubifs_assert(bu->buf_len <= c->leb_size);
|
|
bu->buf = kmalloc(bu->buf_len, GFP_NOFS | __GFP_NOWARN);
|
|
if (!bu->buf)
|
|
goto out_bu_off;
|
|
}
|
|
|
|
err = ubifs_tnc_bulk_read(c, bu);
|
|
if (err)
|
|
goto out_warn;
|
|
}
|
|
|
|
err = populate_page(c, page1, bu, &n);
|
|
if (err)
|
|
goto out_warn;
|
|
|
|
unlock_page(page1);
|
|
ret = 1;
|
|
|
|
isize = i_size_read(inode);
|
|
if (isize == 0)
|
|
goto out_free;
|
|
end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
|
|
|
|
for (page_idx = 1; page_idx < page_cnt; page_idx++) {
|
|
pgoff_t page_offset = offset + page_idx;
|
|
struct page *page;
|
|
|
|
if (page_offset > end_index)
|
|
break;
|
|
page = find_or_create_page(mapping, page_offset,
|
|
GFP_NOFS | __GFP_COLD);
|
|
if (!page)
|
|
break;
|
|
if (!PageUptodate(page))
|
|
err = populate_page(c, page, bu, &n);
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
if (err)
|
|
break;
|
|
}
|
|
|
|
ui->last_page_read = offset + page_idx - 1;
|
|
|
|
out_free:
|
|
if (allocate)
|
|
kfree(bu->buf);
|
|
return ret;
|
|
|
|
out_warn:
|
|
ubifs_warn("ignoring error %d and skipping bulk-read", err);
|
|
goto out_free;
|
|
|
|
out_bu_off:
|
|
ui->read_in_a_row = ui->bulk_read = 0;
|
|
goto out_free;
|
|
}
|
|
|
|
/**
|
|
* ubifs_bulk_read - determine whether to bulk-read and, if so, do it.
|
|
* @page: page from which to start bulk-read.
|
|
*
|
|
* Some flash media are capable of reading sequentially at faster rates. UBIFS
|
|
* bulk-read facility is designed to take advantage of that, by reading in one
|
|
* go consecutive data nodes that are also located consecutively in the same
|
|
* LEB. This function returns %1 if a bulk-read is done and %0 otherwise.
|
|
*/
|
|
static int ubifs_bulk_read(struct page *page)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
pgoff_t index = page->index, last_page_read = ui->last_page_read;
|
|
struct bu_info *bu;
|
|
int err = 0, allocated = 0;
|
|
|
|
ui->last_page_read = index;
|
|
if (!c->bulk_read)
|
|
return 0;
|
|
|
|
/*
|
|
* Bulk-read is protected by @ui->ui_mutex, but it is an optimization,
|
|
* so don't bother if we cannot lock the mutex.
|
|
*/
|
|
if (!mutex_trylock(&ui->ui_mutex))
|
|
return 0;
|
|
|
|
if (index != last_page_read + 1) {
|
|
/* Turn off bulk-read if we stop reading sequentially */
|
|
ui->read_in_a_row = 1;
|
|
if (ui->bulk_read)
|
|
ui->bulk_read = 0;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (!ui->bulk_read) {
|
|
ui->read_in_a_row += 1;
|
|
if (ui->read_in_a_row < 3)
|
|
goto out_unlock;
|
|
/* Three reads in a row, so switch on bulk-read */
|
|
ui->bulk_read = 1;
|
|
}
|
|
|
|
/*
|
|
* If possible, try to use pre-allocated bulk-read information, which
|
|
* is protected by @c->bu_mutex.
|
|
*/
|
|
if (mutex_trylock(&c->bu_mutex))
|
|
bu = &c->bu;
|
|
else {
|
|
bu = kmalloc(sizeof(struct bu_info), GFP_NOFS | __GFP_NOWARN);
|
|
if (!bu)
|
|
goto out_unlock;
|
|
|
|
bu->buf = NULL;
|
|
allocated = 1;
|
|
}
|
|
|
|
bu->buf_len = c->max_bu_buf_len;
|
|
data_key_init(c, &bu->key, inode->i_ino,
|
|
page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT);
|
|
err = ubifs_do_bulk_read(c, bu, page);
|
|
|
|
if (!allocated)
|
|
mutex_unlock(&c->bu_mutex);
|
|
else
|
|
kfree(bu);
|
|
|
|
out_unlock:
|
|
mutex_unlock(&ui->ui_mutex);
|
|
return err;
|
|
}
|
|
|
|
static int ubifs_readpage(struct file *file, struct page *page)
|
|
{
|
|
if (ubifs_bulk_read(page))
|
|
return 0;
|
|
do_readpage(page);
|
|
unlock_page(page);
|
|
return 0;
|
|
}
|
|
|
|
static int do_writepage(struct page *page, int len)
|
|
{
|
|
int err = 0, i, blen;
|
|
unsigned int block;
|
|
void *addr;
|
|
union ubifs_key key;
|
|
struct inode *inode = page->mapping->host;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
|
|
#ifdef UBIFS_DEBUG
|
|
spin_lock(&ui->ui_lock);
|
|
ubifs_assert(page->index <= ui->synced_i_size << PAGE_CACHE_SIZE);
|
|
spin_unlock(&ui->ui_lock);
|
|
#endif
|
|
|
|
/* Update radix tree tags */
|
|
set_page_writeback(page);
|
|
|
|
addr = kmap(page);
|
|
block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
|
|
i = 0;
|
|
while (len) {
|
|
blen = min_t(int, len, UBIFS_BLOCK_SIZE);
|
|
data_key_init(c, &key, inode->i_ino, block);
|
|
err = ubifs_jnl_write_data(c, inode, &key, addr, blen);
|
|
if (err)
|
|
break;
|
|
if (++i >= UBIFS_BLOCKS_PER_PAGE)
|
|
break;
|
|
block += 1;
|
|
addr += blen;
|
|
len -= blen;
|
|
}
|
|
if (err) {
|
|
SetPageError(page);
|
|
ubifs_err("cannot write page %lu of inode %lu, error %d",
|
|
page->index, inode->i_ino, err);
|
|
ubifs_ro_mode(c, err);
|
|
}
|
|
|
|
ubifs_assert(PagePrivate(page));
|
|
if (PageChecked(page))
|
|
release_new_page_budget(c);
|
|
else
|
|
release_existing_page_budget(c);
|
|
|
|
atomic_long_dec(&c->dirty_pg_cnt);
|
|
ClearPagePrivate(page);
|
|
ClearPageChecked(page);
|
|
|
|
kunmap(page);
|
|
unlock_page(page);
|
|
end_page_writeback(page);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* When writing-back dirty inodes, VFS first writes-back pages belonging to the
|
|
* inode, then the inode itself. For UBIFS this may cause a problem. Consider a
|
|
* situation when a we have an inode with size 0, then a megabyte of data is
|
|
* appended to the inode, then write-back starts and flushes some amount of the
|
|
* dirty pages, the journal becomes full, commit happens and finishes, and then
|
|
* an unclean reboot happens. When the file system is mounted next time, the
|
|
* inode size would still be 0, but there would be many pages which are beyond
|
|
* the inode size, they would be indexed and consume flash space. Because the
|
|
* journal has been committed, the replay would not be able to detect this
|
|
* situation and correct the inode size. This means UBIFS would have to scan
|
|
* whole index and correct all inode sizes, which is long an unacceptable.
|
|
*
|
|
* To prevent situations like this, UBIFS writes pages back only if they are
|
|
* within the last synchronized inode size, i.e. the size which has been
|
|
* written to the flash media last time. Otherwise, UBIFS forces inode
|
|
* write-back, thus making sure the on-flash inode contains current inode size,
|
|
* and then keeps writing pages back.
|
|
*
|
|
* Some locking issues explanation. 'ubifs_writepage()' first is called with
|
|
* the page locked, and it locks @ui_mutex. However, write-back does take inode
|
|
* @i_mutex, which means other VFS operations may be run on this inode at the
|
|
* same time. And the problematic one is truncation to smaller size, from where
|
|
* we have to call 'vmtruncate()', which first changes @inode->i_size, then
|
|
* drops the truncated pages. And while dropping the pages, it takes the page
|
|
* lock. This means that 'do_truncation()' cannot call 'vmtruncate()' with
|
|
* @ui_mutex locked, because it would deadlock with 'ubifs_writepage()'. This
|
|
* means that @inode->i_size is changed while @ui_mutex is unlocked.
|
|
*
|
|
* But in 'ubifs_writepage()' we have to guarantee that we do not write beyond
|
|
* inode size. How do we do this if @inode->i_size may became smaller while we
|
|
* are in the middle of 'ubifs_writepage()'? The UBIFS solution is the
|
|
* @ui->ui_isize "shadow" field which UBIFS uses instead of @inode->i_size
|
|
* internally and updates it under @ui_mutex.
|
|
*
|
|
* Q: why we do not worry that if we race with truncation, we may end up with a
|
|
* situation when the inode is truncated while we are in the middle of
|
|
* 'do_writepage()', so we do write beyond inode size?
|
|
* A: If we are in the middle of 'do_writepage()', truncation would be locked
|
|
* on the page lock and it would not write the truncated inode node to the
|
|
* journal before we have finished.
|
|
*/
|
|
static int ubifs_writepage(struct page *page, struct writeback_control *wbc)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
loff_t i_size = i_size_read(inode), synced_i_size;
|
|
pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
|
|
int err, len = i_size & (PAGE_CACHE_SIZE - 1);
|
|
void *kaddr;
|
|
|
|
dbg_gen("ino %lu, pg %lu, pg flags %#lx",
|
|
inode->i_ino, page->index, page->flags);
|
|
ubifs_assert(PagePrivate(page));
|
|
|
|
/* Is the page fully outside @i_size? (truncate in progress) */
|
|
if (page->index > end_index || (page->index == end_index && !len)) {
|
|
err = 0;
|
|
goto out_unlock;
|
|
}
|
|
|
|
spin_lock(&ui->ui_lock);
|
|
synced_i_size = ui->synced_i_size;
|
|
spin_unlock(&ui->ui_lock);
|
|
|
|
/* Is the page fully inside @i_size? */
|
|
if (page->index < end_index) {
|
|
if (page->index >= synced_i_size >> PAGE_CACHE_SHIFT) {
|
|
err = inode->i_sb->s_op->write_inode(inode, 1);
|
|
if (err)
|
|
goto out_unlock;
|
|
/*
|
|
* The inode has been written, but the write-buffer has
|
|
* not been synchronized, so in case of an unclean
|
|
* reboot we may end up with some pages beyond inode
|
|
* size, but they would be in the journal (because
|
|
* commit flushes write buffers) and recovery would deal
|
|
* with this.
|
|
*/
|
|
}
|
|
return do_writepage(page, PAGE_CACHE_SIZE);
|
|
}
|
|
|
|
/*
|
|
* The page straddles @i_size. It must be zeroed out on each and every
|
|
* writepage invocation because it may be mmapped. "A file is mapped
|
|
* in multiples of the page size. For a file that is not a multiple of
|
|
* the page size, the remaining memory is zeroed when mapped, and
|
|
* writes to that region are not written out to the file."
|
|
*/
|
|
kaddr = kmap_atomic(page, KM_USER0);
|
|
memset(kaddr + len, 0, PAGE_CACHE_SIZE - len);
|
|
flush_dcache_page(page);
|
|
kunmap_atomic(kaddr, KM_USER0);
|
|
|
|
if (i_size > synced_i_size) {
|
|
err = inode->i_sb->s_op->write_inode(inode, 1);
|
|
if (err)
|
|
goto out_unlock;
|
|
}
|
|
|
|
return do_writepage(page, len);
|
|
|
|
out_unlock:
|
|
unlock_page(page);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* do_attr_changes - change inode attributes.
|
|
* @inode: inode to change attributes for
|
|
* @attr: describes attributes to change
|
|
*/
|
|
static void do_attr_changes(struct inode *inode, const struct iattr *attr)
|
|
{
|
|
if (attr->ia_valid & ATTR_UID)
|
|
inode->i_uid = attr->ia_uid;
|
|
if (attr->ia_valid & ATTR_GID)
|
|
inode->i_gid = attr->ia_gid;
|
|
if (attr->ia_valid & ATTR_ATIME)
|
|
inode->i_atime = timespec_trunc(attr->ia_atime,
|
|
inode->i_sb->s_time_gran);
|
|
if (attr->ia_valid & ATTR_MTIME)
|
|
inode->i_mtime = timespec_trunc(attr->ia_mtime,
|
|
inode->i_sb->s_time_gran);
|
|
if (attr->ia_valid & ATTR_CTIME)
|
|
inode->i_ctime = timespec_trunc(attr->ia_ctime,
|
|
inode->i_sb->s_time_gran);
|
|
if (attr->ia_valid & ATTR_MODE) {
|
|
umode_t mode = attr->ia_mode;
|
|
|
|
if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
|
|
mode &= ~S_ISGID;
|
|
inode->i_mode = mode;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* do_truncation - truncate an inode.
|
|
* @c: UBIFS file-system description object
|
|
* @inode: inode to truncate
|
|
* @attr: inode attribute changes description
|
|
*
|
|
* This function implements VFS '->setattr()' call when the inode is truncated
|
|
* to a smaller size. Returns zero in case of success and a negative error code
|
|
* in case of failure.
|
|
*/
|
|
static int do_truncation(struct ubifs_info *c, struct inode *inode,
|
|
const struct iattr *attr)
|
|
{
|
|
int err;
|
|
struct ubifs_budget_req req;
|
|
loff_t old_size = inode->i_size, new_size = attr->ia_size;
|
|
int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
|
|
dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size);
|
|
memset(&req, 0, sizeof(struct ubifs_budget_req));
|
|
|
|
/*
|
|
* If this is truncation to a smaller size, and we do not truncate on a
|
|
* block boundary, budget for changing one data block, because the last
|
|
* block will be re-written.
|
|
*/
|
|
if (new_size & (UBIFS_BLOCK_SIZE - 1))
|
|
req.dirtied_page = 1;
|
|
|
|
req.dirtied_ino = 1;
|
|
/* A funny way to budget for truncation node */
|
|
req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ;
|
|
err = ubifs_budget_space(c, &req);
|
|
if (err) {
|
|
/*
|
|
* Treat truncations to zero as deletion and always allow them,
|
|
* just like we do for '->unlink()'.
|
|
*/
|
|
if (new_size || err != -ENOSPC)
|
|
return err;
|
|
budgeted = 0;
|
|
}
|
|
|
|
err = vmtruncate(inode, new_size);
|
|
if (err)
|
|
goto out_budg;
|
|
|
|
if (offset) {
|
|
pgoff_t index = new_size >> PAGE_CACHE_SHIFT;
|
|
struct page *page;
|
|
|
|
page = find_lock_page(inode->i_mapping, index);
|
|
if (page) {
|
|
if (PageDirty(page)) {
|
|
/*
|
|
* 'ubifs_jnl_truncate()' will try to truncate
|
|
* the last data node, but it contains
|
|
* out-of-date data because the page is dirty.
|
|
* Write the page now, so that
|
|
* 'ubifs_jnl_truncate()' will see an already
|
|
* truncated (and up to date) data node.
|
|
*/
|
|
ubifs_assert(PagePrivate(page));
|
|
|
|
clear_page_dirty_for_io(page);
|
|
if (UBIFS_BLOCKS_PER_PAGE_SHIFT)
|
|
offset = new_size &
|
|
(PAGE_CACHE_SIZE - 1);
|
|
err = do_writepage(page, offset);
|
|
page_cache_release(page);
|
|
if (err)
|
|
goto out_budg;
|
|
/*
|
|
* We could now tell 'ubifs_jnl_truncate()' not
|
|
* to read the last block.
|
|
*/
|
|
} else {
|
|
/*
|
|
* We could 'kmap()' the page and pass the data
|
|
* to 'ubifs_jnl_truncate()' to save it from
|
|
* having to read it.
|
|
*/
|
|
unlock_page(page);
|
|
page_cache_release(page);
|
|
}
|
|
}
|
|
}
|
|
|
|
mutex_lock(&ui->ui_mutex);
|
|
ui->ui_size = inode->i_size;
|
|
/* Truncation changes inode [mc]time */
|
|
inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
|
|
/* Other attributes may be changed at the same time as well */
|
|
do_attr_changes(inode, attr);
|
|
err = ubifs_jnl_truncate(c, inode, old_size, new_size);
|
|
mutex_unlock(&ui->ui_mutex);
|
|
|
|
out_budg:
|
|
if (budgeted)
|
|
ubifs_release_budget(c, &req);
|
|
else {
|
|
c->nospace = c->nospace_rp = 0;
|
|
smp_wmb();
|
|
}
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* do_setattr - change inode attributes.
|
|
* @c: UBIFS file-system description object
|
|
* @inode: inode to change attributes for
|
|
* @attr: inode attribute changes description
|
|
*
|
|
* This function implements VFS '->setattr()' call for all cases except
|
|
* truncations to smaller size. Returns zero in case of success and a negative
|
|
* error code in case of failure.
|
|
*/
|
|
static int do_setattr(struct ubifs_info *c, struct inode *inode,
|
|
const struct iattr *attr)
|
|
{
|
|
int err, release;
|
|
loff_t new_size = attr->ia_size;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
struct ubifs_budget_req req = { .dirtied_ino = 1,
|
|
.dirtied_ino_d = ALIGN(ui->data_len, 8) };
|
|
|
|
err = ubifs_budget_space(c, &req);
|
|
if (err)
|
|
return err;
|
|
|
|
if (attr->ia_valid & ATTR_SIZE) {
|
|
dbg_gen("size %lld -> %lld", inode->i_size, new_size);
|
|
err = vmtruncate(inode, new_size);
|
|
if (err)
|
|
goto out;
|
|
}
|
|
|
|
mutex_lock(&ui->ui_mutex);
|
|
if (attr->ia_valid & ATTR_SIZE) {
|
|
/* Truncation changes inode [mc]time */
|
|
inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
|
|
/* 'vmtruncate()' changed @i_size, update @ui_size */
|
|
ui->ui_size = inode->i_size;
|
|
}
|
|
|
|
do_attr_changes(inode, attr);
|
|
|
|
release = ui->dirty;
|
|
if (attr->ia_valid & ATTR_SIZE)
|
|
/*
|
|
* Inode length changed, so we have to make sure
|
|
* @I_DIRTY_DATASYNC is set.
|
|
*/
|
|
__mark_inode_dirty(inode, I_DIRTY_SYNC | I_DIRTY_DATASYNC);
|
|
else
|
|
mark_inode_dirty_sync(inode);
|
|
mutex_unlock(&ui->ui_mutex);
|
|
|
|
if (release)
|
|
ubifs_release_budget(c, &req);
|
|
if (IS_SYNC(inode))
|
|
err = inode->i_sb->s_op->write_inode(inode, 1);
|
|
return err;
|
|
|
|
out:
|
|
ubifs_release_budget(c, &req);
|
|
return err;
|
|
}
|
|
|
|
int ubifs_setattr(struct dentry *dentry, struct iattr *attr)
|
|
{
|
|
int err;
|
|
struct inode *inode = dentry->d_inode;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
|
|
dbg_gen("ino %lu, mode %#x, ia_valid %#x",
|
|
inode->i_ino, inode->i_mode, attr->ia_valid);
|
|
err = inode_change_ok(inode, attr);
|
|
if (err)
|
|
return err;
|
|
|
|
err = dbg_check_synced_i_size(inode);
|
|
if (err)
|
|
return err;
|
|
|
|
if ((attr->ia_valid & ATTR_SIZE) && attr->ia_size < inode->i_size)
|
|
/* Truncation to a smaller size */
|
|
err = do_truncation(c, inode, attr);
|
|
else
|
|
err = do_setattr(c, inode, attr);
|
|
|
|
return err;
|
|
}
|
|
|
|
static void ubifs_invalidatepage(struct page *page, unsigned long offset)
|
|
{
|
|
struct inode *inode = page->mapping->host;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
|
|
ubifs_assert(PagePrivate(page));
|
|
if (offset)
|
|
/* Partial page remains dirty */
|
|
return;
|
|
|
|
if (PageChecked(page))
|
|
release_new_page_budget(c);
|
|
else
|
|
release_existing_page_budget(c);
|
|
|
|
atomic_long_dec(&c->dirty_pg_cnt);
|
|
ClearPagePrivate(page);
|
|
ClearPageChecked(page);
|
|
}
|
|
|
|
static void *ubifs_follow_link(struct dentry *dentry, struct nameidata *nd)
|
|
{
|
|
struct ubifs_inode *ui = ubifs_inode(dentry->d_inode);
|
|
|
|
nd_set_link(nd, ui->data);
|
|
return NULL;
|
|
}
|
|
|
|
int ubifs_fsync(struct file *file, struct dentry *dentry, int datasync)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
int err;
|
|
|
|
dbg_gen("syncing inode %lu", inode->i_ino);
|
|
|
|
/*
|
|
* VFS has already synchronized dirty pages for this inode. Synchronize
|
|
* the inode unless this is a 'datasync()' call.
|
|
*/
|
|
if (!datasync || (inode->i_state & I_DIRTY_DATASYNC)) {
|
|
err = inode->i_sb->s_op->write_inode(inode, 1);
|
|
if (err)
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Nodes related to this inode may still sit in a write-buffer. Flush
|
|
* them.
|
|
*/
|
|
err = ubifs_sync_wbufs_by_inode(c, inode);
|
|
if (err)
|
|
return err;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* mctime_update_needed - check if mtime or ctime update is needed.
|
|
* @inode: the inode to do the check for
|
|
* @now: current time
|
|
*
|
|
* This helper function checks if the inode mtime/ctime should be updated or
|
|
* not. If current values of the time-stamps are within the UBIFS inode time
|
|
* granularity, they are not updated. This is an optimization.
|
|
*/
|
|
static inline int mctime_update_needed(const struct inode *inode,
|
|
const struct timespec *now)
|
|
{
|
|
if (!timespec_equal(&inode->i_mtime, now) ||
|
|
!timespec_equal(&inode->i_ctime, now))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* update_ctime - update mtime and ctime of an inode.
|
|
* @c: UBIFS file-system description object
|
|
* @inode: inode to update
|
|
*
|
|
* This function updates mtime and ctime of the inode if it is not equivalent to
|
|
* current time. Returns zero in case of success and a negative error code in
|
|
* case of failure.
|
|
*/
|
|
static int update_mctime(struct ubifs_info *c, struct inode *inode)
|
|
{
|
|
struct timespec now = ubifs_current_time(inode);
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
|
|
if (mctime_update_needed(inode, &now)) {
|
|
int err, release;
|
|
struct ubifs_budget_req req = { .dirtied_ino = 1,
|
|
.dirtied_ino_d = ALIGN(ui->data_len, 8) };
|
|
|
|
err = ubifs_budget_space(c, &req);
|
|
if (err)
|
|
return err;
|
|
|
|
mutex_lock(&ui->ui_mutex);
|
|
inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
|
|
release = ui->dirty;
|
|
mark_inode_dirty_sync(inode);
|
|
mutex_unlock(&ui->ui_mutex);
|
|
if (release)
|
|
ubifs_release_budget(c, &req);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t ubifs_aio_write(struct kiocb *iocb, const struct iovec *iov,
|
|
unsigned long nr_segs, loff_t pos)
|
|
{
|
|
int err;
|
|
struct inode *inode = iocb->ki_filp->f_mapping->host;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
|
|
err = update_mctime(c, inode);
|
|
if (err)
|
|
return err;
|
|
|
|
return generic_file_aio_write(iocb, iov, nr_segs, pos);
|
|
}
|
|
|
|
static int ubifs_set_page_dirty(struct page *page)
|
|
{
|
|
int ret;
|
|
|
|
ret = __set_page_dirty_nobuffers(page);
|
|
/*
|
|
* An attempt to dirty a page without budgeting for it - should not
|
|
* happen.
|
|
*/
|
|
ubifs_assert(ret == 0);
|
|
return ret;
|
|
}
|
|
|
|
static int ubifs_releasepage(struct page *page, gfp_t unused_gfp_flags)
|
|
{
|
|
/*
|
|
* An attempt to release a dirty page without budgeting for it - should
|
|
* not happen.
|
|
*/
|
|
if (PageWriteback(page))
|
|
return 0;
|
|
ubifs_assert(PagePrivate(page));
|
|
ubifs_assert(0);
|
|
ClearPagePrivate(page);
|
|
ClearPageChecked(page);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* mmap()d file has taken write protection fault and is being made
|
|
* writable. UBIFS must ensure page is budgeted for.
|
|
*/
|
|
static int ubifs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct page *page = vmf->page;
|
|
struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
|
|
struct ubifs_info *c = inode->i_sb->s_fs_info;
|
|
struct timespec now = ubifs_current_time(inode);
|
|
struct ubifs_budget_req req = { .new_page = 1 };
|
|
int err, update_time;
|
|
|
|
dbg_gen("ino %lu, pg %lu, i_size %lld", inode->i_ino, page->index,
|
|
i_size_read(inode));
|
|
ubifs_assert(!(inode->i_sb->s_flags & MS_RDONLY));
|
|
|
|
if (unlikely(c->ro_media))
|
|
return VM_FAULT_SIGBUS; /* -EROFS */
|
|
|
|
/*
|
|
* We have not locked @page so far so we may budget for changing the
|
|
* page. Note, we cannot do this after we locked the page, because
|
|
* budgeting may cause write-back which would cause deadlock.
|
|
*
|
|
* At the moment we do not know whether the page is dirty or not, so we
|
|
* assume that it is not and budget for a new page. We could look at
|
|
* the @PG_private flag and figure this out, but we may race with write
|
|
* back and the page state may change by the time we lock it, so this
|
|
* would need additional care. We do not bother with this at the
|
|
* moment, although it might be good idea to do. Instead, we allocate
|
|
* budget for a new page and amend it later on if the page was in fact
|
|
* dirty.
|
|
*
|
|
* The budgeting-related logic of this function is similar to what we
|
|
* do in 'ubifs_write_begin()' and 'ubifs_write_end()'. Glance there
|
|
* for more comments.
|
|
*/
|
|
update_time = mctime_update_needed(inode, &now);
|
|
if (update_time)
|
|
/*
|
|
* We have to change inode time stamp which requires extra
|
|
* budgeting.
|
|
*/
|
|
req.dirtied_ino = 1;
|
|
|
|
err = ubifs_budget_space(c, &req);
|
|
if (unlikely(err)) {
|
|
if (err == -ENOSPC)
|
|
ubifs_warn("out of space for mmapped file "
|
|
"(inode number %lu)", inode->i_ino);
|
|
return VM_FAULT_SIGBUS;
|
|
}
|
|
|
|
lock_page(page);
|
|
if (unlikely(page->mapping != inode->i_mapping ||
|
|
page_offset(page) > i_size_read(inode))) {
|
|
/* Page got truncated out from underneath us */
|
|
err = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
if (PagePrivate(page))
|
|
release_new_page_budget(c);
|
|
else {
|
|
if (!PageChecked(page))
|
|
ubifs_convert_page_budget(c);
|
|
SetPagePrivate(page);
|
|
atomic_long_inc(&c->dirty_pg_cnt);
|
|
__set_page_dirty_nobuffers(page);
|
|
}
|
|
|
|
if (update_time) {
|
|
int release;
|
|
struct ubifs_inode *ui = ubifs_inode(inode);
|
|
|
|
mutex_lock(&ui->ui_mutex);
|
|
inode->i_mtime = inode->i_ctime = ubifs_current_time(inode);
|
|
release = ui->dirty;
|
|
mark_inode_dirty_sync(inode);
|
|
mutex_unlock(&ui->ui_mutex);
|
|
if (release)
|
|
ubifs_release_dirty_inode_budget(c, ui);
|
|
}
|
|
|
|
unlock_page(page);
|
|
return 0;
|
|
|
|
out_unlock:
|
|
unlock_page(page);
|
|
ubifs_release_budget(c, &req);
|
|
if (err)
|
|
err = VM_FAULT_SIGBUS;
|
|
return err;
|
|
}
|
|
|
|
static const struct vm_operations_struct ubifs_file_vm_ops = {
|
|
.fault = filemap_fault,
|
|
.page_mkwrite = ubifs_vm_page_mkwrite,
|
|
};
|
|
|
|
static int ubifs_file_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
int err;
|
|
|
|
/* 'generic_file_mmap()' takes care of NOMMU case */
|
|
err = generic_file_mmap(file, vma);
|
|
if (err)
|
|
return err;
|
|
vma->vm_ops = &ubifs_file_vm_ops;
|
|
return 0;
|
|
}
|
|
|
|
const struct address_space_operations ubifs_file_address_operations = {
|
|
.readpage = ubifs_readpage,
|
|
.writepage = ubifs_writepage,
|
|
.write_begin = ubifs_write_begin,
|
|
.write_end = ubifs_write_end,
|
|
.invalidatepage = ubifs_invalidatepage,
|
|
.set_page_dirty = ubifs_set_page_dirty,
|
|
.releasepage = ubifs_releasepage,
|
|
};
|
|
|
|
const struct inode_operations ubifs_file_inode_operations = {
|
|
.setattr = ubifs_setattr,
|
|
.getattr = ubifs_getattr,
|
|
#ifdef CONFIG_UBIFS_FS_XATTR
|
|
.setxattr = ubifs_setxattr,
|
|
.getxattr = ubifs_getxattr,
|
|
.listxattr = ubifs_listxattr,
|
|
.removexattr = ubifs_removexattr,
|
|
#endif
|
|
};
|
|
|
|
const struct inode_operations ubifs_symlink_inode_operations = {
|
|
.readlink = generic_readlink,
|
|
.follow_link = ubifs_follow_link,
|
|
.setattr = ubifs_setattr,
|
|
.getattr = ubifs_getattr,
|
|
};
|
|
|
|
const struct file_operations ubifs_file_operations = {
|
|
.llseek = generic_file_llseek,
|
|
.read = do_sync_read,
|
|
.write = do_sync_write,
|
|
.aio_read = generic_file_aio_read,
|
|
.aio_write = ubifs_aio_write,
|
|
.mmap = ubifs_file_mmap,
|
|
.fsync = ubifs_fsync,
|
|
.unlocked_ioctl = ubifs_ioctl,
|
|
.splice_read = generic_file_splice_read,
|
|
.splice_write = generic_file_splice_write,
|
|
#ifdef CONFIG_COMPAT
|
|
.compat_ioctl = ubifs_compat_ioctl,
|
|
#endif
|
|
};
|