~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/bfs/file.c

Version: ~ [ linux-5.10-rc5 ] ~ [ linux-5.9.10 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.79 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.159 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.208 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.245 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.245 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  *      fs/bfs/file.c
  3  *      BFS file operations.
  4  *      Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
  5  *
  6  *      Make the file block allocation algorithm understand the size
  7  *      of the underlying block device.
  8  *      Copyright (C) 2007 Dmitri Vorobiev <dmitri.vorobiev@gmail.com>
  9  *
 10  */
 11 
 12 #include <linux/fs.h>
 13 #include <linux/buffer_head.h>
 14 #include "bfs.h"
 15 
 16 #undef DEBUG
 17 
 18 #ifdef DEBUG
 19 #define dprintf(x...)   printf(x)
 20 #else
 21 #define dprintf(x...)
 22 #endif
 23 
 24 const struct file_operations bfs_file_operations = {
 25         .llseek         = generic_file_llseek,
 26         .read_iter      = generic_file_read_iter,
 27         .write_iter     = generic_file_write_iter,
 28         .mmap           = generic_file_mmap,
 29         .splice_read    = generic_file_splice_read,
 30 };
 31 
 32 static int bfs_move_block(unsigned long from, unsigned long to,
 33                                         struct super_block *sb)
 34 {
 35         struct buffer_head *bh, *new;
 36 
 37         bh = sb_bread(sb, from);
 38         if (!bh)
 39                 return -EIO;
 40         new = sb_getblk(sb, to);
 41         memcpy(new->b_data, bh->b_data, bh->b_size);
 42         mark_buffer_dirty(new);
 43         bforget(bh);
 44         brelse(new);
 45         return 0;
 46 }
 47 
 48 static int bfs_move_blocks(struct super_block *sb, unsigned long start,
 49                                 unsigned long end, unsigned long where)
 50 {
 51         unsigned long i;
 52 
 53         dprintf("%08lx-%08lx->%08lx\n", start, end, where);
 54         for (i = start; i <= end; i++)
 55                 if(bfs_move_block(i, where + i, sb)) {
 56                         dprintf("failed to move block %08lx -> %08lx\n", i,
 57                                                                 where + i);
 58                         return -EIO;
 59                 }
 60         return 0;
 61 }
 62 
 63 static int bfs_get_block(struct inode *inode, sector_t block,
 64                         struct buffer_head *bh_result, int create)
 65 {
 66         unsigned long phys;
 67         int err;
 68         struct super_block *sb = inode->i_sb;
 69         struct bfs_sb_info *info = BFS_SB(sb);
 70         struct bfs_inode_info *bi = BFS_I(inode);
 71 
 72         phys = bi->i_sblock + block;
 73         if (!create) {
 74                 if (phys <= bi->i_eblock) {
 75                         dprintf("c=%d, b=%08lx, phys=%09lx (granted)\n",
 76                                 create, (unsigned long)block, phys);
 77                         map_bh(bh_result, sb, phys);
 78                 }
 79                 return 0;
 80         }
 81 
 82         /*
 83          * If the file is not empty and the requested block is within the
 84          * range of blocks allocated for this file, we can grant it.
 85          */
 86         if (bi->i_sblock && (phys <= bi->i_eblock)) {
 87                 dprintf("c=%d, b=%08lx, phys=%08lx (interim block granted)\n", 
 88                                 create, (unsigned long)block, phys);
 89                 map_bh(bh_result, sb, phys);
 90                 return 0;
 91         }
 92 
 93         /* The file will be extended, so let's see if there is enough space. */
 94         if (phys >= info->si_blocks)
 95                 return -ENOSPC;
 96 
 97         /* The rest has to be protected against itself. */
 98         mutex_lock(&info->bfs_lock);
 99 
100         /*
101          * If the last data block for this file is the last allocated
102          * block, we can extend the file trivially, without moving it
103          * anywhere.
104          */
105         if (bi->i_eblock == info->si_lf_eblk) {
106                 dprintf("c=%d, b=%08lx, phys=%08lx (simple extension)\n", 
107                                 create, (unsigned long)block, phys);
108                 map_bh(bh_result, sb, phys);
109                 info->si_freeb -= phys - bi->i_eblock;
110                 info->si_lf_eblk = bi->i_eblock = phys;
111                 mark_inode_dirty(inode);
112                 err = 0;
113                 goto out;
114         }
115 
116         /* Ok, we have to move this entire file to the next free block. */
117         phys = info->si_lf_eblk + 1;
118         if (phys + block >= info->si_blocks) {
119                 err = -ENOSPC;
120                 goto out;
121         }
122 
123         if (bi->i_sblock) {
124                 err = bfs_move_blocks(inode->i_sb, bi->i_sblock, 
125                                                 bi->i_eblock, phys);
126                 if (err) {
127                         dprintf("failed to move ino=%08lx -> fs corruption\n",
128                                                                 inode->i_ino);
129                         goto out;
130                 }
131         } else
132                 err = 0;
133 
134         dprintf("c=%d, b=%08lx, phys=%08lx (moved)\n",
135                 create, (unsigned long)block, phys);
136         bi->i_sblock = phys;
137         phys += block;
138         info->si_lf_eblk = bi->i_eblock = phys;
139 
140         /*
141          * This assumes nothing can write the inode back while we are here
142          * and thus update inode->i_blocks! (XXX)
143          */
144         info->si_freeb -= bi->i_eblock - bi->i_sblock + 1 - inode->i_blocks;
145         mark_inode_dirty(inode);
146         map_bh(bh_result, sb, phys);
147 out:
148         mutex_unlock(&info->bfs_lock);
149         return err;
150 }
151 
152 static int bfs_writepage(struct page *page, struct writeback_control *wbc)
153 {
154         return block_write_full_page(page, bfs_get_block, wbc);
155 }
156 
157 static int bfs_readpage(struct file *file, struct page *page)
158 {
159         return block_read_full_page(page, bfs_get_block);
160 }
161 
162 static void bfs_write_failed(struct address_space *mapping, loff_t to)
163 {
164         struct inode *inode = mapping->host;
165 
166         if (to > inode->i_size)
167                 truncate_pagecache(inode, inode->i_size);
168 }
169 
170 static int bfs_write_begin(struct file *file, struct address_space *mapping,
171                         loff_t pos, unsigned len, unsigned flags,
172                         struct page **pagep, void **fsdata)
173 {
174         int ret;
175 
176         ret = block_write_begin(mapping, pos, len, flags, pagep,
177                                 bfs_get_block);
178         if (unlikely(ret))
179                 bfs_write_failed(mapping, pos + len);
180 
181         return ret;
182 }
183 
184 static sector_t bfs_bmap(struct address_space *mapping, sector_t block)
185 {
186         return generic_block_bmap(mapping, block, bfs_get_block);
187 }
188 
189 const struct address_space_operations bfs_aops = {
190         .readpage       = bfs_readpage,
191         .writepage      = bfs_writepage,
192         .write_begin    = bfs_write_begin,
193         .write_end      = generic_write_end,
194         .bmap           = bfs_bmap,
195 };
196 
197 const struct inode_operations bfs_file_inops;
198 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp