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![Josef Bacik](/assets/img/avatar_default.png)
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
167 lines
4.4 KiB
C
167 lines
4.4 KiB
C
/*
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* file.c - NILFS regular file handling primitives including fsync().
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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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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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Written by Amagai Yoshiji <amagai@osrg.net>,
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* Ryusuke Konishi <ryusuke@osrg.net>
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*/
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/writeback.h>
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#include "nilfs.h"
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#include "segment.h"
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int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync)
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{
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/*
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* Called from fsync() system call
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* This is the only entry point that can catch write and synch
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* timing for both data blocks and intermediate blocks.
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*
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* This function should be implemented when the writeback function
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* will be implemented.
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*/
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struct inode *inode = file->f_mapping->host;
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int err;
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err = filemap_write_and_wait_range(inode->i_mapping, start, end);
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if (err)
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return err;
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mutex_lock(&inode->i_mutex);
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if (!nilfs_inode_dirty(inode)) {
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mutex_unlock(&inode->i_mutex);
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return 0;
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}
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if (datasync)
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err = nilfs_construct_dsync_segment(inode->i_sb, inode, 0,
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LLONG_MAX);
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else
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err = nilfs_construct_segment(inode->i_sb);
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mutex_unlock(&inode->i_mutex);
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return err;
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}
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static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct page *page = vmf->page;
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struct inode *inode = vma->vm_file->f_dentry->d_inode;
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struct nilfs_transaction_info ti;
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int ret;
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if (unlikely(nilfs_near_disk_full(inode->i_sb->s_fs_info)))
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return VM_FAULT_SIGBUS; /* -ENOSPC */
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lock_page(page);
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if (page->mapping != inode->i_mapping ||
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page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
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unlock_page(page);
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return VM_FAULT_NOPAGE; /* make the VM retry the fault */
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}
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/*
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* check to see if the page is mapped already (no holes)
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*/
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if (PageMappedToDisk(page))
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goto mapped;
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if (page_has_buffers(page)) {
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struct buffer_head *bh, *head;
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int fully_mapped = 1;
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bh = head = page_buffers(page);
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do {
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if (!buffer_mapped(bh)) {
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fully_mapped = 0;
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break;
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}
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} while (bh = bh->b_this_page, bh != head);
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if (fully_mapped) {
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SetPageMappedToDisk(page);
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goto mapped;
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}
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}
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unlock_page(page);
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/*
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* fill hole blocks
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*/
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ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
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/* never returns -ENOMEM, but may return -ENOSPC */
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if (unlikely(ret))
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return VM_FAULT_SIGBUS;
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ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
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if (ret != VM_FAULT_LOCKED) {
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nilfs_transaction_abort(inode->i_sb);
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return ret;
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}
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nilfs_set_file_dirty(inode, 1 << (PAGE_SHIFT - inode->i_blkbits));
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nilfs_transaction_commit(inode->i_sb);
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mapped:
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wait_on_page_writeback(page);
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return VM_FAULT_LOCKED;
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}
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static const struct vm_operations_struct nilfs_file_vm_ops = {
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.fault = filemap_fault,
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.page_mkwrite = nilfs_page_mkwrite,
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};
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static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
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{
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file_accessed(file);
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vma->vm_ops = &nilfs_file_vm_ops;
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vma->vm_flags |= VM_CAN_NONLINEAR;
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return 0;
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}
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/*
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* We have mostly NULL's here: the current defaults are ok for
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* the nilfs filesystem.
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*/
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const struct file_operations nilfs_file_operations = {
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.llseek = generic_file_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = generic_file_aio_read,
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.aio_write = generic_file_aio_write,
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.unlocked_ioctl = nilfs_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = nilfs_compat_ioctl,
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#endif /* CONFIG_COMPAT */
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.mmap = nilfs_file_mmap,
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.open = generic_file_open,
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/* .release = nilfs_release_file, */
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.fsync = nilfs_sync_file,
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.splice_read = generic_file_splice_read,
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};
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const struct inode_operations nilfs_file_inode_operations = {
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.truncate = nilfs_truncate,
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.setattr = nilfs_setattr,
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.permission = nilfs_permission,
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.fiemap = nilfs_fiemap,
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};
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/* end of file */
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