Commit 7097c964 authored by David Howells's avatar David Howells
Browse files

cachefiles: Fix __cachefiles_prepare_write() 



Fix __cachefiles_prepare_write() to correctly determine whether the
requested write will fit correctly with the DIO alignment.

Reported-by: default avatarGao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarYiqun Leng <yqleng@linux.alibaba.com>
Tested-by: default avatarJia Zhu <zhujia.zj@bytedance.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
cc: linux-erofs@lists.ozlabs.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
parent 80105ed2

fs/cachefiles/io.c

+17 −11
Original line number Diff line number Diff line
@@ -522,16 +522,22 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 
			       bool no_space_allocated_yet)

{

	struct cachefiles_cache *cache = object->volume->cache;

	loff_t start = *_start, pos;

	size_t len = *_len, down;

	unsigned long long start = *_start, pos;

	size_t len = *_len;

	int ret;



	/* Round to DIO size */

	down = start - round_down(start, PAGE_SIZE);

	*_start = start - down;

	*_len = round_up(down + len, PAGE_SIZE);

	if (down < start || *_len > upper_len)

	start = round_down(*_start, PAGE_SIZE);

	if (start != *_start) {

		kleave(" = -ENOBUFS [down]");

		return -ENOBUFS;

	}

	if (*_len > upper_len) {

		kleave(" = -ENOBUFS [up]");

		return -ENOBUFS;

	}



	*_len = round_up(len, PAGE_SIZE);



	/* We need to work out whether there's sufficient disk space to perform

	 * the write - but we can skip that check if we have space already
@@ -542,7 +548,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 


	pos = cachefiles_inject_read_error();

	if (pos == 0)

		pos = vfs_llseek(file, *_start, SEEK_DATA);

		pos = vfs_llseek(file, start, SEEK_DATA);

	if (pos < 0 && pos >= (loff_t)-MAX_ERRNO) {

		if (pos == -ENXIO)

			goto check_space; /* Unallocated tail */
@@ -550,7 +556,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 
					  cachefiles_trace_seek_error);

		return pos;

	}

	if ((u64)pos >= (u64)*_start + *_len)

	if (pos >= start + *_len)

		goto check_space; /* Unallocated region */



	/* We have a block that's at least partially filled - if we're low on
@@ -563,13 +569,13 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 


	pos = cachefiles_inject_read_error();

	if (pos == 0)

		pos = vfs_llseek(file, *_start, SEEK_HOLE);

		pos = vfs_llseek(file, start, SEEK_HOLE);

	if (pos < 0 && pos >= (loff_t)-MAX_ERRNO) {

		trace_cachefiles_io_error(object, file_inode(file), pos,

					  cachefiles_trace_seek_error);

		return pos;

	}

	if ((u64)pos >= (u64)*_start + *_len)

	if (pos >= start + *_len)

		return 0; /* Fully allocated */



	/* Partially allocated, but insufficient space: cull. */
@@ -577,7 +583,7 @@ int __cachefiles_prepare_write(struct cachefiles_object *object, 
	ret = cachefiles_inject_remove_error();

	if (ret == 0)

		ret = vfs_fallocate(file, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,

				    *_start, *_len);

				    start, *_len);

	if (ret < 0) {

		trace_cachefiles_io_error(object, file_inode(file), ret,

					  cachefiles_trace_fallocate_error);