openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity
linux/fs/nilfs2/page.h

77 lines
2.4 KiB
C
Raw Normal View History

nilfs2: buffer and page operations This adds common routines for buffer/page operations used in B-tree node caches, meta data files, or segment constructor (log writer). NILFS uses copy functions for buffers and pages due to the following reasons: 1) Relocation required for COW Since NILFS changes address of on-disk blocks, moving buffers in page cache is needed for the buffers which are not addressed by a file offset. If buffer size is smaller than page size, this involves partial copy of pages. 2) Freezing mmapped pages NILFS calculates checksums for each log to ensure its validity. If page data changes after the checksum calculation, this validity check will not work correctly. To avoid this failure for mmaped pages, NILFS freezes their data by copying. 3) Copy-on-write for DAT pages NILFS makes clones of DAT page caches in a copy-on-write manner during GC processes, and this ensures atomicity and consistency of the DAT in the transient state. In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty() and nilfs_clear_page_dirty() respectively. * nilfs_mark_buffer_dirty() was required to avoid NULL pointer dereference faults: Since the page cache of B-tree node pages or data page cache of pseudo inodes does not have a valid mapping->host, calling mark_buffer_dirty() for their buffers causes the fault; it calls __mark_inode_dirty(NULL) through __set_page_dirty(). * nilfs_clear_page_dirty() was needed in the two cases: 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears page dirty flags when it copies back pages from the cloned cache (gcdat->{i_mapping,i_btnode_cache}) to its original cache (dat->{i_mapping,i_btnode_cache}). 2) Some B-tree operations like insertion or deletion may dispose buffers in dirty state, and this needs to cancel the dirty state of their pages. clear_page_dirty_for_io() caused faults because it does not clear the dirty tag on the page cache. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 10:01:27 +08:00
/*
* page.h - buffer/page management specific to NILFS
*
* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Written by Ryusuke Konishi <ryusuke@osrg.net>,
* Seiji Kihara <kihara@osrg.net>.
*/
#ifndef _NILFS_PAGE_H
#define _NILFS_PAGE_H
#include <linux/buffer_head.h>
#include "nilfs.h"
/*
* Extended buffer state bits
*/
enum {
BH_NILFS_Allocated = BH_PrivateStart,
BH_NILFS_Node,
BH_NILFS_Volatile,
nilfs2: introduce check flag to btree node buffer nilfs_btree_get_block() now may return untested buffer due to read-ahead. This adds a new flag for buffer heads so that the btree code can check whether the buffer is already verified or not. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-18 09:42:25 +08:00
BH_NILFS_Checked,
nilfs2: add routines to redirect access to buffers of DAT file During garbage collection (GC), DAT file, which converts virtual block number to real block number, may return disk block number that is not yet written to the device. To avoid access to unwritten blocks, the current implementation stores changes to the caches of GCDAT during GC and atomically commit the changes into the DAT file after they are written to the device. This patch, instead, adds a function that makes a copy of specified buffer and stores it in nilfs_shadow_map, and a function to get the backup copy as needed (nilfs_mdt_freeze_buffer and nilfs_mdt_get_frozen_buffer respectively). Before DAT changes block number in an entry block, it makes a copy and redirect access to the buffer so that address conversion function (i.e. nilfs_dat_translate) refers to the old address saved in the copy. This patch gives requisites for such redirection. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-08-31 10:40:34 +08:00
BH_NILFS_Redirected,
nilfs2: buffer and page operations This adds common routines for buffer/page operations used in B-tree node caches, meta data files, or segment constructor (log writer). NILFS uses copy functions for buffers and pages due to the following reasons: 1) Relocation required for COW Since NILFS changes address of on-disk blocks, moving buffers in page cache is needed for the buffers which are not addressed by a file offset. If buffer size is smaller than page size, this involves partial copy of pages. 2) Freezing mmapped pages NILFS calculates checksums for each log to ensure its validity. If page data changes after the checksum calculation, this validity check will not work correctly. To avoid this failure for mmaped pages, NILFS freezes their data by copying. 3) Copy-on-write for DAT pages NILFS makes clones of DAT page caches in a copy-on-write manner during GC processes, and this ensures atomicity and consistency of the DAT in the transient state. In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty() and nilfs_clear_page_dirty() respectively. * nilfs_mark_buffer_dirty() was required to avoid NULL pointer dereference faults: Since the page cache of B-tree node pages or data page cache of pseudo inodes does not have a valid mapping->host, calling mark_buffer_dirty() for their buffers causes the fault; it calls __mark_inode_dirty(NULL) through __set_page_dirty(). * nilfs_clear_page_dirty() was needed in the two cases: 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears page dirty flags when it copies back pages from the cloned cache (gcdat->{i_mapping,i_btnode_cache}) to its original cache (dat->{i_mapping,i_btnode_cache}). 2) Some B-tree operations like insertion or deletion may dispose buffers in dirty state, and this needs to cancel the dirty state of their pages. clear_page_dirty_for_io() caused faults because it does not clear the dirty tag on the page cache. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 10:01:27 +08:00
};
BUFFER_FNS(NILFS_Node, nilfs_node) /* nilfs node buffers */
BUFFER_FNS(NILFS_Volatile, nilfs_volatile)
nilfs2: introduce check flag to btree node buffer nilfs_btree_get_block() now may return untested buffer due to read-ahead. This adds a new flag for buffer heads so that the btree code can check whether the buffer is already verified or not. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-07-18 09:42:25 +08:00
BUFFER_FNS(NILFS_Checked, nilfs_checked) /* buffer is verified */
nilfs2: add routines to redirect access to buffers of DAT file During garbage collection (GC), DAT file, which converts virtual block number to real block number, may return disk block number that is not yet written to the device. To avoid access to unwritten blocks, the current implementation stores changes to the caches of GCDAT during GC and atomically commit the changes into the DAT file after they are written to the device. This patch, instead, adds a function that makes a copy of specified buffer and stores it in nilfs_shadow_map, and a function to get the backup copy as needed (nilfs_mdt_freeze_buffer and nilfs_mdt_get_frozen_buffer respectively). Before DAT changes block number in an entry block, it makes a copy and redirect access to the buffer so that address conversion function (i.e. nilfs_dat_translate) refers to the old address saved in the copy. This patch gives requisites for such redirection. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-08-31 10:40:34 +08:00
BUFFER_FNS(NILFS_Redirected, nilfs_redirected) /* redirected to a copy */
nilfs2: buffer and page operations This adds common routines for buffer/page operations used in B-tree node caches, meta data files, or segment constructor (log writer). NILFS uses copy functions for buffers and pages due to the following reasons: 1) Relocation required for COW Since NILFS changes address of on-disk blocks, moving buffers in page cache is needed for the buffers which are not addressed by a file offset. If buffer size is smaller than page size, this involves partial copy of pages. 2) Freezing mmapped pages NILFS calculates checksums for each log to ensure its validity. If page data changes after the checksum calculation, this validity check will not work correctly. To avoid this failure for mmaped pages, NILFS freezes their data by copying. 3) Copy-on-write for DAT pages NILFS makes clones of DAT page caches in a copy-on-write manner during GC processes, and this ensures atomicity and consistency of the DAT in the transient state. In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty() and nilfs_clear_page_dirty() respectively. * nilfs_mark_buffer_dirty() was required to avoid NULL pointer dereference faults: Since the page cache of B-tree node pages or data page cache of pseudo inodes does not have a valid mapping->host, calling mark_buffer_dirty() for their buffers causes the fault; it calls __mark_inode_dirty(NULL) through __set_page_dirty(). * nilfs_clear_page_dirty() was needed in the two cases: 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears page dirty flags when it copies back pages from the cloned cache (gcdat->{i_mapping,i_btnode_cache}) to its original cache (dat->{i_mapping,i_btnode_cache}). 2) Some B-tree operations like insertion or deletion may dispose buffers in dirty state, and this needs to cancel the dirty state of their pages. clear_page_dirty_for_io() caused faults because it does not clear the dirty tag on the page cache. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 10:01:27 +08:00
int __nilfs_clear_page_dirty(struct page *);
struct buffer_head *nilfs_grab_buffer(struct inode *, struct address_space *,
unsigned long, unsigned long);
void nilfs_forget_buffer(struct buffer_head *);
void nilfs_copy_buffer(struct buffer_head *, struct buffer_head *);
int nilfs_page_buffers_clean(struct page *);
void nilfs_page_bug(struct page *);
int nilfs_copy_dirty_pages(struct address_space *, struct address_space *);
void nilfs_copy_back_pages(struct address_space *, struct address_space *);
nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption The NILFS2 driver remounts itself in RO mode in the case of discovering metadata corruption (for example, discovering a broken bmap). But usually, this takes place when there have been file system operations before remounting in RO mode. Thereby, NILFS2 driver can be in RO mode with presence of dirty pages in modified inodes' address spaces. It results in flush kernel thread's infinite trying to flush dirty pages in RO mode. As a result, it is possible to see such side effects as: (1) flush kernel thread occupies 50% - 99% of CPU time; (2) system can't be shutdowned without manual power switch off. SYMPTOMS: (1) System log contains error message: "Remounting filesystem read-only". (2) The flush kernel thread occupies 50% - 99% of CPU time. (3) The system can't be shutdowned without manual power switch off. REPRODUCTION PATH: (1) Create volume group with name "unencrypted" by means of vgcreate utility. (2) Run script (prepared by Anthony Doggett <Anthony2486@interfaces.org.uk>): ----------------[BEGIN SCRIPT]-------------------- #!/bin/bash VG=unencrypted #apt-get install nilfs-tools darcs lvcreate --size 2G --name ntest $VG mkfs.nilfs2 -b 1024 -B 8192 /dev/mapper/$VG-ntest mkdir /var/tmp/n mkdir /var/tmp/n/ntest mount /dev/mapper/$VG-ntest /var/tmp/n/ntest mkdir /var/tmp/n/ntest/thedir cd /var/tmp/n/ntest/thedir sleep 2 date darcs init sleep 2 dmesg|tail -n 5 date darcs whatsnew || true date sleep 2 dmesg|tail -n 5 ----------------[END SCRIPT]-------------------- (3) Try to shutdown the system. REPRODUCIBILITY: 100% FIX: This patch implements checking mount state of NILFS2 driver in nilfs_writepage(), nilfs_writepages() and nilfs_mdt_write_page() methods. If it is detected the RO mount state then all dirty pages are simply discarded with warning messages is written in system log. [akpm@linux-foundation.org: fix printk warning] Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Anthony Doggett <Anthony2486@interfaces.org.uk> Cc: ARAI Shun-ichi <hermes@ceres.dti.ne.jp> Cc: Piotr Szymaniak <szarpaj@grubelek.pl> Cc: Zahid Chowdhury <zahid.chowdhury@starsolutions.com> Cc: Elmer Zhang <freeboy6716@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-05-01 06:27:48 +08:00
void nilfs_clear_dirty_page(struct page *, bool);
void nilfs_clear_dirty_pages(struct address_space *, bool);
fs: remove mapping->backing_dev_info Now that we never use the backing_dev_info pointer in struct address_space we can simply remove it and save 4 to 8 bytes in every inode. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-01-14 17:42:37 +08:00
void nilfs_mapping_init(struct address_space *mapping, struct inode *inode);
nilfs2: buffer and page operations This adds common routines for buffer/page operations used in B-tree node caches, meta data files, or segment constructor (log writer). NILFS uses copy functions for buffers and pages due to the following reasons: 1) Relocation required for COW Since NILFS changes address of on-disk blocks, moving buffers in page cache is needed for the buffers which are not addressed by a file offset. If buffer size is smaller than page size, this involves partial copy of pages. 2) Freezing mmapped pages NILFS calculates checksums for each log to ensure its validity. If page data changes after the checksum calculation, this validity check will not work correctly. To avoid this failure for mmaped pages, NILFS freezes their data by copying. 3) Copy-on-write for DAT pages NILFS makes clones of DAT page caches in a copy-on-write manner during GC processes, and this ensures atomicity and consistency of the DAT in the transient state. In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty() and nilfs_clear_page_dirty() respectively. * nilfs_mark_buffer_dirty() was required to avoid NULL pointer dereference faults: Since the page cache of B-tree node pages or data page cache of pseudo inodes does not have a valid mapping->host, calling mark_buffer_dirty() for their buffers causes the fault; it calls __mark_inode_dirty(NULL) through __set_page_dirty(). * nilfs_clear_page_dirty() was needed in the two cases: 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears page dirty flags when it copies back pages from the cloned cache (gcdat->{i_mapping,i_btnode_cache}) to its original cache (dat->{i_mapping,i_btnode_cache}). 2) Some B-tree operations like insertion or deletion may dispose buffers in dirty state, and this needs to cancel the dirty state of their pages. clear_page_dirty_for_io() caused faults because it does not clear the dirty tag on the page cache. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 10:01:27 +08:00
unsigned nilfs_page_count_clean_buffers(struct page *, unsigned, unsigned);
nilfs2: fiemap support This adds fiemap to nilfs. Two new functions, nilfs_fiemap and nilfs_find_uncommitted_extent are added. nilfs_fiemap() implements the fiemap inode operation, and nilfs_find_uncommitted_extent() helps to get a range of data blocks whose physical location has not been determined. nilfs_fiemap() collects extent information by looping through nilfs_bmap_lookup_contig and nilfs_find_uncommitted_extent routines. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
2010-12-26 15:38:43 +08:00
unsigned long nilfs_find_uncommitted_extent(struct inode *inode,
sector_t start_blk,
sector_t *blkoff);
nilfs2: buffer and page operations This adds common routines for buffer/page operations used in B-tree node caches, meta data files, or segment constructor (log writer). NILFS uses copy functions for buffers and pages due to the following reasons: 1) Relocation required for COW Since NILFS changes address of on-disk blocks, moving buffers in page cache is needed for the buffers which are not addressed by a file offset. If buffer size is smaller than page size, this involves partial copy of pages. 2) Freezing mmapped pages NILFS calculates checksums for each log to ensure its validity. If page data changes after the checksum calculation, this validity check will not work correctly. To avoid this failure for mmaped pages, NILFS freezes their data by copying. 3) Copy-on-write for DAT pages NILFS makes clones of DAT page caches in a copy-on-write manner during GC processes, and this ensures atomicity and consistency of the DAT in the transient state. In addition, NILFS uses two obsolete functions, nilfs_mark_buffer_dirty() and nilfs_clear_page_dirty() respectively. * nilfs_mark_buffer_dirty() was required to avoid NULL pointer dereference faults: Since the page cache of B-tree node pages or data page cache of pseudo inodes does not have a valid mapping->host, calling mark_buffer_dirty() for their buffers causes the fault; it calls __mark_inode_dirty(NULL) through __set_page_dirty(). * nilfs_clear_page_dirty() was needed in the two cases: 1) For B-tree node pages and data pages of the dat/gcdat, NILFS2 clears page dirty flags when it copies back pages from the cloned cache (gcdat->{i_mapping,i_btnode_cache}) to its original cache (dat->{i_mapping,i_btnode_cache}). 2) Some B-tree operations like insertion or deletion may dispose buffers in dirty state, and this needs to cancel the dirty state of their pages. clear_page_dirty_for_io() caused faults because it does not clear the dirty tag on the page cache. Signed-off-by: Seiji Kihara <kihara.seiji@lab.ntt.co.jp> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 10:01:27 +08:00
#define NILFS_PAGE_BUG(page, m, a...) \
do { nilfs_page_bug(page); BUG(); } while (0)
static inline struct buffer_head *
nilfs_page_get_nth_block(struct page *page, unsigned int count)
{
struct buffer_head *bh = page_buffers(page);
while (count-- > 0)
bh = bh->b_this_page;
get_bh(bh);
return bh;
}
#endif /* _NILFS_PAGE_H */