nilfs2: segment constructor
[linux-2.6.git] / fs / nilfs2 / file.c
1 /*
2  * file.c - NILFS regular file handling primitives including fsync().
3  *
4  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
19  *
20  * Written by Amagai Yoshiji <amagai@osrg.net>,
21  *            Ryusuke Konishi <ryusuke@osrg.net>
22  */
23
24 #include <linux/fs.h>
25 #include <linux/mm.h>
26 #include <linux/writeback.h>
27 #include "nilfs.h"
28 #include "segment.h"
29
30 int nilfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
31 {
32         /*
33          * Called from fsync() system call
34          * This is the only entry point that can catch write and synch
35          * timing for both data blocks and intermediate blocks.
36          *
37          * This function should be implemented when the writeback function
38          * will be implemented.
39          */
40         struct inode *inode = dentry->d_inode;
41         int err;
42
43         if (!nilfs_inode_dirty(inode))
44                 return 0;
45
46         if (datasync)
47                 err = nilfs_construct_dsync_segment(inode->i_sb, inode);
48         else
49                 err = nilfs_construct_segment(inode->i_sb);
50
51         return err;
52 }
53
54 static ssize_t
55 nilfs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
56                      unsigned long nr_segs, loff_t pos)
57 {
58         struct file *file = iocb->ki_filp;
59         struct inode *inode = file->f_dentry->d_inode;
60         ssize_t ret;
61
62         ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
63         if (ret <= 0)
64                 return ret;
65
66         if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
67                 int err;
68
69                 err = nilfs_construct_dsync_segment(inode->i_sb, inode);
70                 if (unlikely(err))
71                         return err;
72         }
73         return ret;
74 }
75
76 static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
77 {
78         struct page *page = vmf->page;
79         struct inode *inode = vma->vm_file->f_dentry->d_inode;
80         struct nilfs_transaction_info ti;
81         int ret;
82
83         if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
84                 return VM_FAULT_SIGBUS; /* -ENOSPC */
85
86         lock_page(page);
87         if (page->mapping != inode->i_mapping ||
88             page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
89                 unlock_page(page);
90                 return VM_FAULT_NOPAGE; /* make the VM retry the fault */
91         }
92
93         /*
94          * check to see if the page is mapped already (no holes)
95          */
96         if (PageMappedToDisk(page)) {
97                 unlock_page(page);
98                 goto mapped;
99         }
100         if (page_has_buffers(page)) {
101                 struct buffer_head *bh, *head;
102                 int fully_mapped = 1;
103
104                 bh = head = page_buffers(page);
105                 do {
106                         if (!buffer_mapped(bh)) {
107                                 fully_mapped = 0;
108                                 break;
109                         }
110                 } while (bh = bh->b_this_page, bh != head);
111
112                 if (fully_mapped) {
113                         SetPageMappedToDisk(page);
114                         unlock_page(page);
115                         goto mapped;
116                 }
117         }
118         unlock_page(page);
119
120         /*
121          * fill hole blocks
122          */
123         ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
124         /* never returns -ENOMEM, but may return -ENOSPC */
125         if (unlikely(ret))
126                 return VM_FAULT_SIGBUS;
127
128         ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
129         if (unlikely(ret)) {
130                 nilfs_transaction_abort(inode->i_sb);
131                 return ret;
132         }
133         nilfs_transaction_commit(inode->i_sb);
134
135  mapped:
136         SetPageChecked(page);
137         wait_on_page_writeback(page);
138         return 0;
139 }
140
141 struct vm_operations_struct nilfs_file_vm_ops = {
142         .fault          = filemap_fault,
143         .page_mkwrite   = nilfs_page_mkwrite,
144 };
145
146 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
147 {
148         file_accessed(file);
149         vma->vm_ops = &nilfs_file_vm_ops;
150         vma->vm_flags |= VM_CAN_NONLINEAR;
151         return 0;
152 }
153
154 /*
155  * We have mostly NULL's here: the current defaults are ok for
156  * the nilfs filesystem.
157  */
158 struct file_operations nilfs_file_operations = {
159         .llseek         = generic_file_llseek,
160         .read           = do_sync_read,
161         .write          = do_sync_write,
162         .aio_read       = generic_file_aio_read,
163         .aio_write      = nilfs_file_aio_write,
164         .ioctl          = nilfs_ioctl,
165 #ifdef CONFIG_COMPAT
166         .compat_ioctl   = nilfs_compat_ioctl,
167 #endif  /* CONFIG_COMPAT */
168         .mmap           = nilfs_file_mmap,
169         .open           = generic_file_open,
170         /* .release     = nilfs_release_file, */
171         .fsync          = nilfs_sync_file,
172         .splice_read    = generic_file_splice_read,
173 };
174
175 struct inode_operations nilfs_file_inode_operations = {
176         .truncate       = nilfs_truncate,
177         .setattr        = nilfs_setattr,
178         .permission     = nilfs_permission,
179 };
180
181 /* end of file */