Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 1 | /* |
| 2 | * fs/logfs/file.c - prepare_write, commit_write and friends |
| 3 | * |
| 4 | * As should be obvious for Linux kernel code, license is GPLv2 |
| 5 | * |
| 6 | * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> |
| 7 | */ |
| 8 | #include "logfs.h" |
| 9 | #include <linux/sched.h> |
| 10 | #include <linux/writeback.h> |
| 11 | |
| 12 | static int logfs_write_begin(struct file *file, struct address_space *mapping, |
| 13 | loff_t pos, unsigned len, unsigned flags, |
| 14 | struct page **pagep, void **fsdata) |
| 15 | { |
| 16 | struct inode *inode = mapping->host; |
| 17 | struct page *page; |
| 18 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
| 19 | |
| 20 | page = grab_cache_page_write_begin(mapping, index, flags); |
| 21 | if (!page) |
| 22 | return -ENOMEM; |
| 23 | *pagep = page; |
| 24 | |
| 25 | if ((len == PAGE_CACHE_SIZE) || PageUptodate(page)) |
| 26 | return 0; |
| 27 | if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) { |
| 28 | unsigned start = pos & (PAGE_CACHE_SIZE - 1); |
| 29 | unsigned end = start + len; |
| 30 | |
| 31 | /* Reading beyond i_size is simple: memset to zero */ |
| 32 | zero_user_segments(page, 0, start, end, PAGE_CACHE_SIZE); |
| 33 | return 0; |
| 34 | } |
| 35 | return logfs_readpage_nolock(page); |
| 36 | } |
| 37 | |
| 38 | static int logfs_write_end(struct file *file, struct address_space *mapping, |
| 39 | loff_t pos, unsigned len, unsigned copied, struct page *page, |
| 40 | void *fsdata) |
| 41 | { |
| 42 | struct inode *inode = mapping->host; |
| 43 | pgoff_t index = page->index; |
| 44 | unsigned start = pos & (PAGE_CACHE_SIZE - 1); |
| 45 | unsigned end = start + copied; |
| 46 | int ret = 0; |
| 47 | |
| 48 | BUG_ON(PAGE_CACHE_SIZE != inode->i_sb->s_blocksize); |
| 49 | BUG_ON(page->index > I3_BLOCKS); |
| 50 | |
| 51 | if (copied < len) { |
| 52 | /* |
| 53 | * Short write of a non-initialized paged. Just tell userspace |
| 54 | * to retry the entire page. |
| 55 | */ |
| 56 | if (!PageUptodate(page)) { |
| 57 | copied = 0; |
| 58 | goto out; |
| 59 | } |
| 60 | } |
| 61 | if (copied == 0) |
| 62 | goto out; /* FIXME: do we need to update inode? */ |
| 63 | |
| 64 | if (i_size_read(inode) < (index << PAGE_CACHE_SHIFT) + end) { |
| 65 | i_size_write(inode, (index << PAGE_CACHE_SHIFT) + end); |
| 66 | mark_inode_dirty_sync(inode); |
| 67 | } |
| 68 | |
| 69 | SetPageUptodate(page); |
| 70 | if (!PageDirty(page)) { |
| 71 | if (!get_page_reserve(inode, page)) |
| 72 | __set_page_dirty_nobuffers(page); |
| 73 | else |
| 74 | ret = logfs_write_buf(inode, page, WF_LOCK); |
| 75 | } |
| 76 | out: |
| 77 | unlock_page(page); |
| 78 | page_cache_release(page); |
| 79 | return ret ? ret : copied; |
| 80 | } |
| 81 | |
| 82 | int logfs_readpage(struct file *file, struct page *page) |
| 83 | { |
| 84 | int ret; |
| 85 | |
| 86 | ret = logfs_readpage_nolock(page); |
| 87 | unlock_page(page); |
| 88 | return ret; |
| 89 | } |
| 90 | |
| 91 | /* Clear the page's dirty flag in the radix tree. */ |
| 92 | /* TODO: mucking with PageWriteback is silly. Add a generic function to clear |
| 93 | * the dirty bit from the radix tree for filesystems that don't have to wait |
| 94 | * for page writeback to finish (i.e. any compressing filesystem). |
| 95 | */ |
| 96 | static void clear_radix_tree_dirty(struct page *page) |
| 97 | { |
| 98 | BUG_ON(PagePrivate(page) || page->private); |
| 99 | set_page_writeback(page); |
| 100 | end_page_writeback(page); |
| 101 | } |
| 102 | |
| 103 | static int __logfs_writepage(struct page *page) |
| 104 | { |
| 105 | struct inode *inode = page->mapping->host; |
| 106 | int err; |
| 107 | |
| 108 | err = logfs_write_buf(inode, page, WF_LOCK); |
| 109 | if (err) |
| 110 | set_page_dirty(page); |
| 111 | else |
| 112 | clear_radix_tree_dirty(page); |
| 113 | unlock_page(page); |
| 114 | return err; |
| 115 | } |
| 116 | |
| 117 | static int logfs_writepage(struct page *page, struct writeback_control *wbc) |
| 118 | { |
| 119 | struct inode *inode = page->mapping->host; |
| 120 | loff_t i_size = i_size_read(inode); |
| 121 | pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; |
| 122 | unsigned offset; |
| 123 | u64 bix; |
| 124 | level_t level; |
| 125 | |
| 126 | log_file("logfs_writepage(%lx, %lx, %p)\n", inode->i_ino, page->index, |
| 127 | page); |
| 128 | |
| 129 | logfs_unpack_index(page->index, &bix, &level); |
| 130 | |
| 131 | /* Indirect blocks are never truncated */ |
| 132 | if (level != 0) |
| 133 | return __logfs_writepage(page); |
| 134 | |
| 135 | /* |
| 136 | * TODO: everything below is a near-verbatim copy of nobh_writepage(). |
| 137 | * The relevant bits should be factored out after logfs is merged. |
| 138 | */ |
| 139 | |
| 140 | /* Is the page fully inside i_size? */ |
| 141 | if (bix < end_index) |
| 142 | return __logfs_writepage(page); |
| 143 | |
| 144 | /* Is the page fully outside i_size? (truncate in progress) */ |
| 145 | offset = i_size & (PAGE_CACHE_SIZE-1); |
| 146 | if (bix > end_index || offset == 0) { |
| 147 | unlock_page(page); |
| 148 | return 0; /* don't care */ |
| 149 | } |
| 150 | |
| 151 | /* |
| 152 | * The page straddles i_size. It must be zeroed out on each and every |
| 153 | * writepage invokation because it may be mmapped. "A file is mapped |
| 154 | * in multiples of the page size. For a file that is not a multiple of |
| 155 | * the page size, the remaining memory is zeroed when mapped, and |
| 156 | * writes to that region are not written out to the file." |
| 157 | */ |
| 158 | zero_user_segment(page, offset, PAGE_CACHE_SIZE); |
| 159 | return __logfs_writepage(page); |
| 160 | } |
| 161 | |
| 162 | static void logfs_invalidatepage(struct page *page, unsigned long offset) |
| 163 | { |
Joern Engel | 05ebad8 | 2010-05-04 19:41:09 +0200 | [diff] [blame] | 164 | struct logfs_block *block = logfs_block(page); |
| 165 | |
| 166 | if (block->reserved_bytes) { |
| 167 | struct super_block *sb = page->mapping->host->i_sb; |
| 168 | struct logfs_super *super = logfs_super(sb); |
| 169 | |
| 170 | super->s_dirty_pages -= block->reserved_bytes; |
| 171 | block->ops->free_block(sb, block); |
| 172 | BUG_ON(bitmap_weight(block->alias_map, LOGFS_BLOCK_FACTOR)); |
| 173 | } else |
| 174 | move_page_to_btree(page); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 175 | BUG_ON(PagePrivate(page) || page->private); |
| 176 | } |
| 177 | |
| 178 | static int logfs_releasepage(struct page *page, gfp_t only_xfs_uses_this) |
| 179 | { |
| 180 | return 0; /* None of these are easy to release */ |
| 181 | } |
| 182 | |
| 183 | |
Arnd Bergmann | 02d6d68 | 2010-04-27 22:30:06 +0200 | [diff] [blame] | 184 | long logfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 185 | { |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 186 | struct inode *inode = file_inode(file); |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 187 | struct logfs_inode *li = logfs_inode(inode); |
| 188 | unsigned int oldflags, flags; |
| 189 | int err; |
| 190 | |
| 191 | switch (cmd) { |
| 192 | case FS_IOC_GETFLAGS: |
| 193 | flags = li->li_flags & LOGFS_FL_USER_VISIBLE; |
| 194 | return put_user(flags, (int __user *)arg); |
| 195 | case FS_IOC_SETFLAGS: |
| 196 | if (IS_RDONLY(inode)) |
| 197 | return -EROFS; |
| 198 | |
Serge E. Hallyn | 2e14967 | 2011-03-23 16:43:26 -0700 | [diff] [blame] | 199 | if (!inode_owner_or_capable(inode)) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 200 | return -EACCES; |
| 201 | |
| 202 | err = get_user(flags, (int __user *)arg); |
| 203 | if (err) |
| 204 | return err; |
| 205 | |
| 206 | mutex_lock(&inode->i_mutex); |
| 207 | oldflags = li->li_flags; |
| 208 | flags &= LOGFS_FL_USER_MODIFIABLE; |
| 209 | flags |= oldflags & ~LOGFS_FL_USER_MODIFIABLE; |
| 210 | li->li_flags = flags; |
| 211 | mutex_unlock(&inode->i_mutex); |
| 212 | |
| 213 | inode->i_ctime = CURRENT_TIME; |
| 214 | mark_inode_dirty_sync(inode); |
| 215 | return 0; |
| 216 | |
| 217 | default: |
| 218 | return -ENOTTY; |
| 219 | } |
| 220 | } |
| 221 | |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 222 | int logfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 223 | { |
Christoph Hellwig | 7ea8085 | 2010-05-26 17:53:25 +0200 | [diff] [blame] | 224 | struct super_block *sb = file->f_mapping->host->i_sb; |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 225 | struct inode *inode = file->f_mapping->host; |
| 226 | int ret; |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 227 | |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 228 | ret = filemap_write_and_wait_range(inode->i_mapping, start, end); |
| 229 | if (ret) |
| 230 | return ret; |
| 231 | |
| 232 | mutex_lock(&inode->i_mutex); |
Prasad Joshi | 13ced29 | 2012-01-28 11:36:06 +0530 | [diff] [blame] | 233 | logfs_get_wblocks(sb, NULL, WF_LOCK); |
Joern Engel | c0c79c3 | 2010-05-05 22:33:36 +0200 | [diff] [blame] | 234 | logfs_write_anchor(sb); |
Prasad Joshi | 13ced29 | 2012-01-28 11:36:06 +0530 | [diff] [blame] | 235 | logfs_put_wblocks(sb, NULL, WF_LOCK); |
Josef Bacik | 02c24a8 | 2011-07-16 20:44:56 -0400 | [diff] [blame] | 236 | mutex_unlock(&inode->i_mutex); |
| 237 | |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 238 | return 0; |
| 239 | } |
| 240 | |
| 241 | static int logfs_setattr(struct dentry *dentry, struct iattr *attr) |
| 242 | { |
| 243 | struct inode *inode = dentry->d_inode; |
| 244 | int err = 0; |
| 245 | |
Christoph Hellwig | db78b87 | 2010-06-04 11:30:03 +0200 | [diff] [blame] | 246 | err = inode_change_ok(inode, attr); |
| 247 | if (err) |
| 248 | return err; |
| 249 | |
Christoph Hellwig | 1025774 | 2010-06-04 11:30:02 +0200 | [diff] [blame] | 250 | if (attr->ia_valid & ATTR_SIZE) { |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 251 | err = logfs_truncate(inode, attr->ia_size); |
Christoph Hellwig | 1025774 | 2010-06-04 11:30:02 +0200 | [diff] [blame] | 252 | if (err) |
| 253 | return err; |
| 254 | } |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 255 | |
Christoph Hellwig | 1025774 | 2010-06-04 11:30:02 +0200 | [diff] [blame] | 256 | setattr_copy(inode, attr); |
| 257 | mark_inode_dirty(inode); |
| 258 | return 0; |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 259 | } |
| 260 | |
| 261 | const struct inode_operations logfs_reg_iops = { |
| 262 | .setattr = logfs_setattr, |
| 263 | }; |
| 264 | |
| 265 | const struct file_operations logfs_reg_fops = { |
| 266 | .aio_read = generic_file_aio_read, |
| 267 | .aio_write = generic_file_aio_write, |
| 268 | .fsync = logfs_fsync, |
Arnd Bergmann | 02d6d68 | 2010-04-27 22:30:06 +0200 | [diff] [blame] | 269 | .unlocked_ioctl = logfs_ioctl, |
Joern Engel | 5db53f3 | 2009-11-20 20:13:39 +0100 | [diff] [blame] | 270 | .llseek = generic_file_llseek, |
| 271 | .mmap = generic_file_readonly_mmap, |
| 272 | .open = generic_file_open, |
| 273 | .read = do_sync_read, |
| 274 | .write = do_sync_write, |
| 275 | }; |
| 276 | |
| 277 | const struct address_space_operations logfs_reg_aops = { |
| 278 | .invalidatepage = logfs_invalidatepage, |
| 279 | .readpage = logfs_readpage, |
| 280 | .releasepage = logfs_releasepage, |
| 281 | .set_page_dirty = __set_page_dirty_nobuffers, |
| 282 | .writepage = logfs_writepage, |
| 283 | .writepages = generic_writepages, |
| 284 | .write_begin = logfs_write_begin, |
| 285 | .write_end = logfs_write_end, |
| 286 | }; |