| /* |
| * fs/logfs/file.c - prepare_write, commit_write and friends |
| * |
| * As should be obvious for Linux kernel code, license is GPLv2 |
| * |
| * Copyright (c) 2005-2008 Joern Engel <joern@logfs.org> |
| */ |
| #include "logfs.h" |
| #include <linux/sched.h> |
| #include <linux/writeback.h> |
| |
| static int logfs_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **pagep, void **fsdata) |
| { |
| struct inode *inode = mapping->host; |
| struct page *page; |
| pgoff_t index = pos >> PAGE_SHIFT; |
| |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (!page) |
| return -ENOMEM; |
| *pagep = page; |
| |
| if ((len == PAGE_SIZE) || PageUptodate(page)) |
| return 0; |
| if ((pos & PAGE_MASK) >= i_size_read(inode)) { |
| unsigned start = pos & (PAGE_SIZE - 1); |
| unsigned end = start + len; |
| |
| /* Reading beyond i_size is simple: memset to zero */ |
| zero_user_segments(page, 0, start, end, PAGE_SIZE); |
| return 0; |
| } |
| return logfs_readpage_nolock(page); |
| } |
| |
| static int logfs_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, struct page *page, |
| void *fsdata) |
| { |
| struct inode *inode = mapping->host; |
| pgoff_t index = page->index; |
| unsigned start = pos & (PAGE_SIZE - 1); |
| unsigned end = start + copied; |
| int ret = 0; |
| |
| BUG_ON(PAGE_SIZE != inode->i_sb->s_blocksize); |
| BUG_ON(page->index > I3_BLOCKS); |
| |
| if (copied < len) { |
| /* |
| * Short write of a non-initialized paged. Just tell userspace |
| * to retry the entire page. |
| */ |
| if (!PageUptodate(page)) { |
| copied = 0; |
| goto out; |
| } |
| } |
| if (copied == 0) |
| goto out; /* FIXME: do we need to update inode? */ |
| |
| if (i_size_read(inode) < (index << PAGE_SHIFT) + end) { |
| i_size_write(inode, (index << PAGE_SHIFT) + end); |
| mark_inode_dirty_sync(inode); |
| } |
| |
| SetPageUptodate(page); |
| if (!PageDirty(page)) { |
| if (!get_page_reserve(inode, page)) |
| __set_page_dirty_nobuffers(page); |
| else |
| ret = logfs_write_buf(inode, page, WF_LOCK); |
| } |
| out: |
| unlock_page(page); |
| put_page(page); |
| return ret ? ret : copied; |
| } |
| |
| int logfs_readpage(struct file *file, struct page *page) |
| { |
| int ret; |
| |
| ret = logfs_readpage_nolock(page); |
| unlock_page(page); |
| return ret; |
| } |
| |
| /* Clear the page's dirty flag in the radix tree. */ |
| /* TODO: mucking with PageWriteback is silly. Add a generic function to clear |
| * the dirty bit from the radix tree for filesystems that don't have to wait |
| * for page writeback to finish (i.e. any compressing filesystem). |
| */ |
| static void clear_radix_tree_dirty(struct page *page) |
| { |
| BUG_ON(PagePrivate(page) || page->private); |
| set_page_writeback(page); |
| end_page_writeback(page); |
| } |
| |
| static int __logfs_writepage(struct page *page) |
| { |
| struct inode *inode = page->mapping->host; |
| int err; |
| |
| err = logfs_write_buf(inode, page, WF_LOCK); |
| if (err) |
| set_page_dirty(page); |
| else |
| clear_radix_tree_dirty(page); |
| unlock_page(page); |
| return err; |
| } |
| |
| static int logfs_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| struct inode *inode = page->mapping->host; |
| loff_t i_size = i_size_read(inode); |
| pgoff_t end_index = i_size >> PAGE_SHIFT; |
| unsigned offset; |
| u64 bix; |
| level_t level; |
| |
| log_file("logfs_writepage(%lx, %lx, %p)\n", inode->i_ino, page->index, |
| page); |
| |
| logfs_unpack_index(page->index, &bix, &level); |
| |
| /* Indirect blocks are never truncated */ |
| if (level != 0) |
| return __logfs_writepage(page); |
| |
| /* |
| * TODO: everything below is a near-verbatim copy of nobh_writepage(). |
| * The relevant bits should be factored out after logfs is merged. |
| */ |
| |
| /* Is the page fully inside i_size? */ |
| if (bix < end_index) |
| return __logfs_writepage(page); |
| |
| /* Is the page fully outside i_size? (truncate in progress) */ |
| offset = i_size & (PAGE_SIZE-1); |
| if (bix > end_index || offset == 0) { |
| unlock_page(page); |
| return 0; /* don't care */ |
| } |
| |
| /* |
| * The page straddles i_size. It must be zeroed out on each and every |
| * writepage invokation because it may be mmapped. "A file is mapped |
| * in multiples of the page size. For a file that is not a multiple of |
| * the page size, the remaining memory is zeroed when mapped, and |
| * writes to that region are not written out to the file." |
| */ |
| zero_user_segment(page, offset, PAGE_SIZE); |
| return __logfs_writepage(page); |
| } |
| |
| static void logfs_invalidatepage(struct page *page, unsigned int offset, |
| unsigned int length) |
| { |
| struct logfs_block *block = logfs_block(page); |
| |
| if (block->reserved_bytes) { |
| struct super_block *sb = page->mapping->host->i_sb; |
| struct logfs_super *super = logfs_super(sb); |
| |
| super->s_dirty_pages -= block->reserved_bytes; |
| block->ops->free_block(sb, block); |
| BUG_ON(bitmap_weight(block->alias_map, LOGFS_BLOCK_FACTOR)); |
| } else |
| move_page_to_btree(page); |
| BUG_ON(PagePrivate(page) || page->private); |
| } |
| |
| static int logfs_releasepage(struct page *page, gfp_t only_xfs_uses_this) |
| { |
| return 0; /* None of these are easy to release */ |
| } |
| |
| |
| long logfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) |
| { |
| struct inode *inode = file_inode(file); |
| struct logfs_inode *li = logfs_inode(inode); |
| unsigned int oldflags, flags; |
| int err; |
| |
| switch (cmd) { |
| case FS_IOC_GETFLAGS: |
| flags = li->li_flags & LOGFS_FL_USER_VISIBLE; |
| return put_user(flags, (int __user *)arg); |
| case FS_IOC_SETFLAGS: |
| if (IS_RDONLY(inode)) |
| return -EROFS; |
| |
| if (!inode_owner_or_capable(inode)) |
| return -EACCES; |
| |
| err = get_user(flags, (int __user *)arg); |
| if (err) |
| return err; |
| |
| inode_lock(inode); |
| oldflags = li->li_flags; |
| flags &= LOGFS_FL_USER_MODIFIABLE; |
| flags |= oldflags & ~LOGFS_FL_USER_MODIFIABLE; |
| li->li_flags = flags; |
| inode_unlock(inode); |
| |
| inode->i_ctime = current_time(inode); |
| mark_inode_dirty_sync(inode); |
| return 0; |
| |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| int logfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| { |
| struct super_block *sb = file->f_mapping->host->i_sb; |
| struct inode *inode = file->f_mapping->host; |
| int ret; |
| |
| ret = filemap_write_and_wait_range(inode->i_mapping, start, end); |
| if (ret) |
| return ret; |
| |
| inode_lock(inode); |
| logfs_get_wblocks(sb, NULL, WF_LOCK); |
| logfs_write_anchor(sb); |
| logfs_put_wblocks(sb, NULL, WF_LOCK); |
| inode_unlock(inode); |
| |
| return 0; |
| } |
| |
| static int logfs_setattr(struct dentry *dentry, struct iattr *attr) |
| { |
| struct inode *inode = d_inode(dentry); |
| int err = 0; |
| |
| err = inode_change_ok(inode, attr); |
| if (err) |
| return err; |
| |
| if (attr->ia_valid & ATTR_SIZE) { |
| err = logfs_truncate(inode, attr->ia_size); |
| if (err) |
| return err; |
| } |
| |
| setattr_copy(inode, attr); |
| mark_inode_dirty(inode); |
| return 0; |
| } |
| |
| const struct inode_operations logfs_reg_iops = { |
| .setattr = logfs_setattr, |
| }; |
| |
| const struct file_operations logfs_reg_fops = { |
| .read_iter = generic_file_read_iter, |
| .write_iter = generic_file_write_iter, |
| .fsync = logfs_fsync, |
| .unlocked_ioctl = logfs_ioctl, |
| .llseek = generic_file_llseek, |
| .mmap = generic_file_readonly_mmap, |
| .open = generic_file_open, |
| }; |
| |
| const struct address_space_operations logfs_reg_aops = { |
| .invalidatepage = logfs_invalidatepage, |
| .readpage = logfs_readpage, |
| .releasepage = logfs_releasepage, |
| .set_page_dirty = __set_page_dirty_nobuffers, |
| .writepage = logfs_writepage, |
| .writepages = generic_writepages, |
| .write_begin = logfs_write_begin, |
| .write_end = logfs_write_end, |
| }; |