irqchip/qcom-pdc: Switch to IRQCHIP_PLATFORM_DRIVER and allow as a module
[linux-2.6-microblaze.git] / fs / bfs / file.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *      fs/bfs/file.c
4  *      BFS file operations.
5  *      Copyright (C) 1999-2018 Tigran Aivazian <aivazian.tigran@gmail.com>
6  *
7  *      Make the file block allocation algorithm understand the size
8  *      of the underlying block device.
9  *      Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
10  *
11  */
12
13 #include <linux/fs.h>
14 #include <linux/buffer_head.h>
15 #include "bfs.h"
16
17 #undef DEBUG
18
19 #ifdef DEBUG
20 #define dprintf(x...)   printf(x)
21 #else
22 #define dprintf(x...)
23 #endif
24
25 const struct file_operations bfs_file_operations = {
26         .llseek         = generic_file_llseek,
27         .read_iter      = generic_file_read_iter,
28         .write_iter     = generic_file_write_iter,
29         .mmap           = generic_file_mmap,
30         .splice_read    = generic_file_splice_read,
31 };
32
33 static int bfs_move_block(unsigned long from, unsigned long to,
34                                         struct super_block *sb)
35 {
36         struct buffer_head *bh, *new;
37
38         bh = sb_bread(sb, from);
39         if (!bh)
40                 return -EIO;
41         new = sb_getblk(sb, to);
42         memcpy(new->b_data, bh->b_data, bh->b_size);
43         mark_buffer_dirty(new);
44         bforget(bh);
45         brelse(new);
46         return 0;
47 }
48
49 static int bfs_move_blocks(struct super_block *sb, unsigned long start,
50                                 unsigned long end, unsigned long where)
51 {
52         unsigned long i;
53
54         dprintf("%08lx-%08lx->%08lx\n", start, end, where);
55         for (i = start; i <= end; i++)
56                 if(bfs_move_block(i, where + i, sb)) {
57                         dprintf("failed to move block %08lx -> %08lx\n", i,
58                                                                 where + i);
59                         return -EIO;
60                 }
61         return 0;
62 }
63
64 static int bfs_get_block(struct inode *inode, sector_t block,
65                         struct buffer_head *bh_result, int create)
66 {
67         unsigned long phys;
68         int err;
69         struct super_block *sb = inode->i_sb;
70         struct bfs_sb_info *info = BFS_SB(sb);
71         struct bfs_inode_info *bi = BFS_I(inode);
72
73         phys = bi->i_sblock + block;
74         if (!create) {
75                 if (phys <= bi->i_eblock) {
76                         dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
77                                 create, (unsigned long)block, phys);
78                         map_bh(bh_result, sb, phys);
79                 }
80                 return 0;
81         }
82
83         /*
84          * If the file is not empty and the requested block is within the
85          * range of blocks allocated for this file, we can grant it.
86          */
87         if (bi->i_sblock && (phys <= bi->i_eblock)) {
88                 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", 
89                                 create, (unsigned long)block, phys);
90                 map_bh(bh_result, sb, phys);
91                 return 0;
92         }
93
94         /* The file will be extended, so let's see if there is enough space. */
95         if (phys >= info->si_blocks)
96                 return -ENOSPC;
97
98         /* The rest has to be protected against itself. */
99         mutex_lock(&info->bfs_lock);
100
101         /*
102          * If the last data block for this file is the last allocated
103          * block, we can extend the file trivially, without moving it
104          * anywhere.
105          */
106         if (bi->i_eblock == info->si_lf_eblk) {
107                 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", 
108                                 create, (unsigned long)block, phys);
109                 map_bh(bh_result, sb, phys);
110                 info->si_freeb -= phys - bi->i_eblock;
111                 info->si_lf_eblk = bi->i_eblock = phys;
112                 mark_inode_dirty(inode);
113                 err = 0;
114                 goto out;
115         }
116
117         /* Ok, we have to move this entire file to the next free block. */
118         phys = info->si_lf_eblk + 1;
119         if (phys + block >= info->si_blocks) {
120                 err = -ENOSPC;
121                 goto out;
122         }
123
124         if (bi->i_sblock) {
125                 err = bfs_move_blocks(inode->i_sb, bi->i_sblock, 
126                                                 bi->i_eblock, phys);
127                 if (err) {
128                         dprintf("failed to move ino=%08lx -> fs corruption\n",
129                                                                 inode->i_ino);
130                         goto out;
131                 }
132         } else
133                 err = 0;
134
135         dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
136                 create, (unsigned long)block, phys);
137         bi->i_sblock = phys;
138         phys += block;
139         info->si_lf_eblk = bi->i_eblock = phys;
140
141         /*
142          * This assumes nothing can write the inode back while we are here
143          * and thus update inode->i_blocks! (XXX)
144          */
145         info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
146         mark_inode_dirty(inode);
147         map_bh(bh_result, sb, phys);
148 out:
149         mutex_unlock(&info->bfs_lock);
150         return err;
151 }
152
153 static int bfs_writepage(struct page *page, struct writeback_control *wbc)
154 {
155         return block_write_full_page(page, bfs_get_block, wbc);
156 }
157
158 static int bfs_readpage(struct file *file, struct page *page)
159 {
160         return block_read_full_page(page, bfs_get_block);
161 }
162
163 static void bfs_write_failed(struct address_space *mapping, loff_t to)
164 {
165         struct inode *inode = mapping->host;
166
167         if (to > inode->i_size)
168                 truncate_pagecache(inode, inode->i_size);
169 }
170
171 static int bfs_write_begin(struct file *file, struct address_space *mapping,
172                         loff_t pos, unsigned len, unsigned flags,
173                         struct page **pagep, void **fsdata)
174 {
175         int ret;
176
177         ret = block_write_begin(mapping, pos, len, flags, pagep,
178                                 bfs_get_block);
179         if (unlikely(ret))
180                 bfs_write_failed(mapping, pos + len);
181
182         return ret;
183 }
184
185 static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
186 {
187         return generic_block_bmap(mapping, block, bfs_get_block);
188 }
189
190 const struct address_space_operations bfs_aops = {
191         .readpage       = bfs_readpage,
192         .writepage      = bfs_writepage,
193         .write_begin    = bfs_write_begin,
194         .write_end      = generic_write_end,
195         .bmap           = bfs_bmap,
196 };
197
198 const struct inode_operations bfs_file_inops;