Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6
[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, 0,
48                                                     LLONG_MAX);
49         else
50                 err = nilfs_construct_segment(inode->i_sb);
51
52         return err;
53 }
54
55 static int nilfs_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
56 {
57         struct page *page = vmf->page;
58         struct inode *inode = vma->vm_file->f_dentry->d_inode;
59         struct nilfs_transaction_info ti;
60         int ret;
61
62         if (unlikely(nilfs_near_disk_full(NILFS_SB(inode->i_sb)->s_nilfs)))
63                 return VM_FAULT_SIGBUS; /* -ENOSPC */
64
65         lock_page(page);
66         if (page->mapping != inode->i_mapping ||
67             page_offset(page) >= i_size_read(inode) || !PageUptodate(page)) {
68                 unlock_page(page);
69                 return VM_FAULT_NOPAGE; /* make the VM retry the fault */
70         }
71
72         /*
73          * check to see if the page is mapped already (no holes)
74          */
75         if (PageMappedToDisk(page)) {
76                 unlock_page(page);
77                 goto mapped;
78         }
79         if (page_has_buffers(page)) {
80                 struct buffer_head *bh, *head;
81                 int fully_mapped = 1;
82
83                 bh = head = page_buffers(page);
84                 do {
85                         if (!buffer_mapped(bh)) {
86                                 fully_mapped = 0;
87                                 break;
88                         }
89                 } while (bh = bh->b_this_page, bh != head);
90
91                 if (fully_mapped) {
92                         SetPageMappedToDisk(page);
93                         unlock_page(page);
94                         goto mapped;
95                 }
96         }
97         unlock_page(page);
98
99         /*
100          * fill hole blocks
101          */
102         ret = nilfs_transaction_begin(inode->i_sb, &ti, 1);
103         /* never returns -ENOMEM, but may return -ENOSPC */
104         if (unlikely(ret))
105                 return VM_FAULT_SIGBUS;
106
107         ret = block_page_mkwrite(vma, vmf, nilfs_get_block);
108         if (unlikely(ret)) {
109                 nilfs_transaction_abort(inode->i_sb);
110                 return ret;
111         }
112         nilfs_transaction_commit(inode->i_sb);
113
114  mapped:
115         SetPageChecked(page);
116         wait_on_page_writeback(page);
117         return 0;
118 }
119
120 static const struct vm_operations_struct nilfs_file_vm_ops = {
121         .fault          = filemap_fault,
122         .page_mkwrite   = nilfs_page_mkwrite,
123 };
124
125 static int nilfs_file_mmap(struct file *file, struct vm_area_struct *vma)
126 {
127         file_accessed(file);
128         vma->vm_ops = &nilfs_file_vm_ops;
129         vma->vm_flags |= VM_CAN_NONLINEAR;
130         return 0;
131 }
132
133 /*
134  * We have mostly NULL's here: the current defaults are ok for
135  * the nilfs filesystem.
136  */
137 const struct file_operations nilfs_file_operations = {
138         .llseek         = generic_file_llseek,
139         .read           = do_sync_read,
140         .write          = do_sync_write,
141         .aio_read       = generic_file_aio_read,
142         .aio_write      = generic_file_aio_write,
143         .unlocked_ioctl = nilfs_ioctl,
144 #ifdef CONFIG_COMPAT
145         .compat_ioctl   = nilfs_ioctl,
146 #endif  /* CONFIG_COMPAT */
147         .mmap           = nilfs_file_mmap,
148         .open           = generic_file_open,
149         /* .release     = nilfs_release_file, */
150         .fsync          = nilfs_sync_file,
151         .splice_read    = generic_file_splice_read,
152 };
153
154 const struct inode_operations nilfs_file_inode_operations = {
155         .truncate       = nilfs_truncate,
156         .setattr        = nilfs_setattr,
157         .permission     = nilfs_permission,
158 };
159
160 /* end of file */