Commit 36ee1313 authored by Namjae Jeon's avatar Namjae Jeon
Browse files

ntfs: use page allocation for resident attribute inline data 



The current kmemdup() based allocation for IOMAP_INLINE can result in
inline_data pointer having a non-zero page offset. This causes
iomap_inline_data_valid() to fail the check:

    iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data)

and triggers the kernel BUG at fs/iomap/buffered-io.c:1061.

This particularly affects workloads with frequent small file access
(e.g. Firefox Nightly profile on NTFS with bind mount) when using the
new ntfs. This fix this by allocating a full page with alloc_page() so that
page_address() always returns a page-aligned address.

Reviewed-by: default avatarHyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
parent 6e0152c7

fs/ntfs/iomap.c

+19 −7
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ static int ntfs_read_iomap_begin_resident(struct inode *inode, loff_t offset, lo 
	u32 attr_len;

	int err = 0;

	char *kattr;

	struct page *ipage;



	if (NInoAttr(ni))

		base_ni = ni->ext.base_ntfs_ino;
@@ -129,15 +130,18 @@ static int ntfs_read_iomap_begin_resident(struct inode *inode, loff_t offset, lo 


	kattr = (u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset);



	iomap->inline_data = kmemdup(kattr, attr_len, GFP_KERNEL);

	if (!iomap->inline_data) {

	ipage = alloc_page(GFP_NOFS | __GFP_ZERO);

	if (!ipage) {

		err = -ENOMEM;

		goto out;

	}



	memcpy(page_address(ipage), kattr, attr_len);

	iomap->type = IOMAP_INLINE;

	iomap->inline_data = page_address(ipage);

	iomap->offset = 0;

	iomap->length = attr_len;

	iomap->private = ipage;



out:

	if (ctx)
@@ -285,8 +289,11 @@ static int ntfs_read_iomap_begin(struct inode *inode, loff_t offset, loff_t leng 
static int ntfs_read_iomap_end(struct inode *inode, loff_t pos, loff_t length,

		ssize_t written, unsigned int flags, struct iomap *iomap)

{

	if (iomap->type == IOMAP_INLINE)

		kfree(iomap->inline_data);

	if (iomap->type == IOMAP_INLINE) {

		struct page *ipage = iomap->private;



		put_page(ipage);

	}



	return written;

}
@@ -652,6 +659,7 @@ static int ntfs_write_iomap_begin_resident(struct inode *inode, loff_t offset, 
	u32 attr_len;

	int err = 0;

	char *kattr;

	struct page *ipage;



	ctx = ntfs_attr_get_search_ctx(ni, NULL);

	if (!ctx) {
@@ -672,16 +680,19 @@ static int ntfs_write_iomap_begin_resident(struct inode *inode, loff_t offset, 
	attr_len = le32_to_cpu(a->data.resident.value_length);

	kattr = (u8 *)a + le16_to_cpu(a->data.resident.value_offset);



	iomap->inline_data = kmemdup(kattr, attr_len, GFP_KERNEL);

	if (!iomap->inline_data) {

	ipage = alloc_page(GFP_NOFS | __GFP_ZERO);

	if (!ipage) {

		err = -ENOMEM;

		goto out;

	}



	memcpy(page_address(ipage), kattr, attr_len);

	iomap->type = IOMAP_INLINE;

	iomap->inline_data = page_address(ipage);

	iomap->offset = 0;

	/* iomap requires there is only one INLINE_DATA extent */

	iomap->length = attr_len;

	iomap->private = ipage;



out:

	if (ctx)
@@ -771,6 +782,7 @@ static int ntfs_write_iomap_end_resident(struct inode *inode, loff_t pos, 
	u32 attr_len;

	int err;

	char *kattr;

	struct page *ipage = iomap->private;



	mutex_lock(&ni->mrec_lock);

	ctx = ntfs_attr_get_search_ctx(ni, NULL);
@@ -799,7 +811,7 @@ static int ntfs_write_iomap_end_resident(struct inode *inode, loff_t pos, 
	mark_mft_record_dirty(ctx->ntfs_ino);

err_out:

	ntfs_attr_put_search_ctx(ctx);

	kfree(iomap->inline_data);

	put_page(ipage);

	mutex_unlock(&ni->mrec_lock);

	return written;