--- fs/logfs/file.c | 263 ++++ diff --git a/fs/logfs/file.c b/fs/logfs/file.c new file mode 100644 index 0000000..370f367 --- /dev/null +++ b/fs/logfs/file.c @@ -0,0 +1,263 @@ +/* + * 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@xxxxxxxxx> + */ +#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_CACHE_SHIFT; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + *pagep = page; + + if ((len == PAGE_CACHE_SIZE) || PageUptodate(page)) + return 0; + if ((pos & PAGE_CACHE_MASK) >= i_size_read(inode)) { + unsigned start = pos & (PAGE_CACHE_SIZE - 1); + unsigned end = start + len; + + /* Reading beyond i_size is simple: memset to zero */ + zero_user_segments(page, 0, start, end, PAGE_CACHE_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_CACHE_SIZE - 1); + unsigned end = start + copied; + int ret = 0; + + BUG_ON(PAGE_CACHE_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_CACHE_SHIFT) + end) { + i_size_write(inode, (index << PAGE_CACHE_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); + page_cache_release(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_CACHE_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_CACHE_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_CACHE_SIZE); + return __logfs_writepage(page); +} + +static void logfs_invalidatepage(struct page *page, unsigned long offset) +{ + 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 */ +} + + +int logfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, + unsigned long arg) +{ + 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 (!is_owner_or_cap(inode)) + return -EACCES; + + err = get_user(flags, (int __user *)arg); + if (err) + return err; + + mutex_lock(&inode->i_mutex); + oldflags = li->li_flags; + flags &= LOGFS_FL_USER_MODIFIABLE; + flags |= oldflags & ~LOGFS_FL_USER_MODIFIABLE; + li->li_flags = flags; + mutex_unlock(&inode->i_mutex); + + inode->i_ctime = CURRENT_TIME; + mark_inode_dirty_sync(inode); + return 0; + + default: + return -ENOTTY; + } +} + +int logfs_fsync(struct file *file, struct dentry *dentry, int datasync) +{ + struct super_block *sb = dentry->d_inode->i_sb; + struct logfs_super *super = logfs_super(sb); + + /* FIXME: write anchor */ + super->s_devops->sync(sb); + return 0; +} + +static int logfs_setattr(struct dentry *dentry, struct iattr *attr) +{ + struct inode *inode = dentry->d_inode; + int err = 0; + + if (attr->ia_valid & ATTR_SIZE) + err = logfs_truncate(inode, attr->ia_size); + attr->ia_valid &= ~ATTR_SIZE; + + if (!err) + err = inode_change_ok(inode, attr); + if (!err) + err = inode_setattr(inode, attr); + return err; +} + +const struct inode_operations logfs_reg_iops = { + .setattr = logfs_setattr, +}; + +const struct file_operations logfs_reg_fops = { + .aio_read = generic_file_aio_read, + .aio_write = generic_file_aio_write, + .fsync = logfs_fsync, + .ioctl = logfs_ioctl, + .llseek = generic_file_llseek, + .mmap = generic_file_readonly_mmap, + .open = generic_file_open, + .read = do_sync_read, + .write = do_sync_write, +}; + +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, +}; -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html