X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Flibfs.c;h=232bea425b09155a1f116981e4e53283a1738bbc;hb=d27d7a9a7838587fcdcc6f2b042f5610eb4984a1;hp=ddfa89948c3f1e6cbf553f213883cb2ca2a4ed5e;hpb=d5aacad548db1ff547adf35d0a77eb2a8ed4fe14;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/libfs.c b/fs/libfs.c index ddfa899..232bea4 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -5,6 +5,7 @@ #include #include +#include #include #include #include @@ -217,7 +218,7 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name, return PTR_ERR(s); s->s_flags = MS_NOUSER; - s->s_maxbytes = ~0ULL; + s->s_maxbytes = MAX_LFS_FILESIZE; s->s_blocksize = PAGE_SIZE; s->s_blocksize_bits = PAGE_SHIFT; s->s_magic = magic; @@ -338,28 +339,14 @@ int simple_readpage(struct file *file, struct page *page) return 0; } -int simple_prepare_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - if (!PageUptodate(page)) { - if (to - from != PAGE_CACHE_SIZE) - zero_user_segments(page, - 0, from, - to, PAGE_CACHE_SIZE); - } - return 0; -} - int simple_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct page *page; pgoff_t index; - unsigned from; index = pos >> PAGE_CACHE_SHIFT; - from = pos & (PAGE_CACHE_SIZE - 1); page = grab_cache_page_write_begin(mapping, index, flags); if (!page) @@ -367,43 +354,59 @@ int simple_write_begin(struct file *file, struct address_space *mapping, *pagep = page; - return simple_prepare_write(file, page, from, from+len); -} - -static int simple_commit_write(struct file *file, struct page *page, - unsigned from, unsigned to) -{ - struct inode *inode = page->mapping->host; - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; + if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) { + unsigned from = pos & (PAGE_CACHE_SIZE - 1); - if (!PageUptodate(page)) - SetPageUptodate(page); - /* - * No need to use i_size_read() here, the i_size - * cannot change under us because we hold the i_mutex. - */ - if (pos > inode->i_size) - i_size_write(inode, pos); - set_page_dirty(page); + zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE); + } return 0; } +/** + * simple_write_end - .write_end helper for non-block-device FSes + * @available: See .write_end of address_space_operations + * @file: " + * @mapping: " + * @pos: " + * @len: " + * @copied: " + * @page: " + * @fsdata: " + * + * simple_write_end does the minimum needed for updating a page after writing is + * done. It has the same API signature as the .write_end of + * address_space_operations vector. So it can just be set onto .write_end for + * FSes that don't need any other processing. i_mutex is assumed to be held. + * Block based filesystems should use generic_write_end(). + * NOTE: Even though i_size might get updated by this function, mark_inode_dirty + * is not called, so a filesystem that actually does store data in .write_inode + * should extend on what's done here with a call to mark_inode_dirty() in the + * case that i_size has changed. + */ int simple_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { - unsigned from = pos & (PAGE_CACHE_SIZE - 1); + struct inode *inode = page->mapping->host; + loff_t last_pos = pos + copied; /* zero the stale part of the page if we did a short copy */ if (copied < len) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + from + copied, 0, len - copied); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + + zero_user(page, from + copied, len - copied); } - simple_commit_write(file, page, from, from+copied); + if (!PageUptodate(page)) + SetPageUptodate(page); + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold the i_mutex. + */ + if (last_pos > inode->i_size) + i_size_write(inode, last_pos); + set_page_dirty(page); unlock_page(page); page_cache_release(page); @@ -527,14 +530,52 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos, const void *from, size_t available) { loff_t pos = *ppos; + size_t ret; + if (pos < 0) return -EINVAL; - if (pos >= available) + if (pos >= available || !count) + return 0; + if (count > available - pos) + count = available - pos; + ret = copy_to_user(to, from + pos, count); + if (ret == count) + return -EFAULT; + count -= ret; + *ppos = pos + count; + return count; +} + +/** + * simple_write_to_buffer - copy data from user space to the buffer + * @to: the buffer to write to + * @available: the size of the buffer + * @ppos: the current position in the buffer + * @from: the user space buffer to read from + * @count: the maximum number of bytes to read + * + * The simple_write_to_buffer() function reads up to @count bytes from the user + * space address starting at @from into the buffer @to at offset @ppos. + * + * On success, the number of bytes written is returned and the offset @ppos is + * advanced by this number, or negative value is returned on error. + **/ +ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos, + const void __user *from, size_t count) +{ + loff_t pos = *ppos; + size_t res; + + if (pos < 0) + return -EINVAL; + if (pos >= available || !count) return 0; if (count > available - pos) count = available - pos; - if (copy_to_user(to, from + pos, count)) + res = copy_from_user(to + pos, from, count); + if (res == count) return -EFAULT; + count -= res; *ppos = pos + count; return count; } @@ -735,10 +776,11 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, if (copy_from_user(attr->set_buf, buf, size)) goto out; - ret = len; /* claim we got the whole input */ attr->set_buf[size] = '\0'; val = simple_strtol(attr->set_buf, NULL, 0); - attr->set(attr->data, val); + ret = attr->set(attr->data, val); + if (ret == 0) + ret = len; /* on success, claim we got the whole input */ out: mutex_unlock(&attr->mutex); return ret; @@ -843,13 +885,11 @@ EXPORT_SYMBOL(simple_write_end); EXPORT_SYMBOL(simple_dir_inode_operations); EXPORT_SYMBOL(simple_dir_operations); EXPORT_SYMBOL(simple_empty); -EXPORT_SYMBOL(d_alloc_name); EXPORT_SYMBOL(simple_fill_super); EXPORT_SYMBOL(simple_getattr); EXPORT_SYMBOL(simple_link); EXPORT_SYMBOL(simple_lookup); EXPORT_SYMBOL(simple_pin_fs); -EXPORT_UNUSED_SYMBOL(simple_prepare_write); EXPORT_SYMBOL(simple_readpage); EXPORT_SYMBOL(simple_release_fs); EXPORT_SYMBOL(simple_rename); @@ -858,6 +898,7 @@ EXPORT_SYMBOL(simple_statfs); EXPORT_SYMBOL(simple_sync_file); EXPORT_SYMBOL(simple_unlink); EXPORT_SYMBOL(simple_read_from_buffer); +EXPORT_SYMBOL(simple_write_to_buffer); EXPORT_SYMBOL(memory_read_from_buffer); EXPORT_SYMBOL(simple_transaction_set); EXPORT_SYMBOL(simple_transaction_get);