Commit 5c5c5e51 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
Browse files

fuse: update file size on short read 



If the READ request returned a short count, then either

  - cached size is incorrect
  - filesystem is buggy, as short reads are only allowed on EOF

So assume that the size is wrong and refresh it, so that cached read() doesn't
zero fill the missing chunk.

Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ea9b9907

fs/fuse/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -132,7 +132,7 @@ static void fuse_lookup_init(struct fuse_req *req, struct inode *dir, 
	req->out.args[0].value = outarg;

}



static u64 fuse_get_attr_version(struct fuse_conn *fc)

u64 fuse_get_attr_version(struct fuse_conn *fc)

{

	u64 curr_version;

fs/fuse/file.c

+46 −6
Original line number Diff line number Diff line
@@ -363,7 +363,7 @@ static int fuse_fsync(struct file *file, struct dentry *de, int datasync) 
void fuse_read_fill(struct fuse_req *req, struct file *file,

		    struct inode *inode, loff_t pos, size_t count, int opcode)

{

	struct fuse_read_in *inarg = &req->misc.read_in;

	struct fuse_read_in *inarg = &req->misc.read.in;

	struct fuse_file *ff = file->private_data;



	inarg->fh = ff->fh;
@@ -389,7 +389,7 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file, 


	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);

	if (owner != NULL) {

		struct fuse_read_in *inarg = &req->misc.read_in;

		struct fuse_read_in *inarg = &req->misc.read.in;



		inarg->read_flags |= FUSE_READ_LOCKOWNER;

		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
@@ -398,11 +398,29 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file, 
	return req->out.args[0].size;

}



static void fuse_read_update_size(struct inode *inode, loff_t size,

				  u64 attr_ver)

{

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_inode *fi = get_fuse_inode(inode);



	spin_lock(&fc->lock);

	if (attr_ver == fi->attr_version && size < inode->i_size) {

		fi->attr_version = ++fc->attr_version;

		i_size_write(inode, size);

	}

	spin_unlock(&fc->lock);

}



static int fuse_readpage(struct file *file, struct page *page)

{

	struct inode *inode = page->mapping->host;

	struct fuse_conn *fc = get_fuse_conn(inode);

	struct fuse_req *req;

	size_t num_read;

	loff_t pos = page_offset(page);

	size_t count = PAGE_CACHE_SIZE;

	u64 attr_ver;

	int err;



	err = -EIO;
@@ -421,15 +439,25 @@ static int fuse_readpage(struct file *file, struct page *page) 
	if (IS_ERR(req))

		goto out;



	attr_ver = fuse_get_attr_version(fc);



	req->out.page_zeroing = 1;

	req->num_pages = 1;

	req->pages[0] = page;

	fuse_send_read(req, file, inode, page_offset(page), PAGE_CACHE_SIZE,

		       NULL);

	num_read = fuse_send_read(req, file, inode, pos, count, NULL);

	err = req->out.h.error;

	fuse_put_request(fc, req);

	if (!err)



	if (!err) {

		/*

		 * Short read means EOF.  If file size is larger, truncate it

		 */

		if (num_read < count)

			fuse_read_update_size(inode, pos + num_read, attr_ver);



		SetPageUptodate(page);

	}



	fuse_invalidate_attr(inode); /* atime changed */

 out:

	unlock_page(page);
@@ -439,8 +467,19 @@ static int fuse_readpage(struct file *file, struct page *page) 
static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)

{

	int i;

	size_t count = req->misc.read.in.size;

	size_t num_read = req->out.args[0].size;

	struct inode *inode = req->pages[0]->mapping->host;



	/*

	 * Short read means EOF.  If file size is larger, truncate it

	 */

	if (!req->out.h.error && num_read < count) {

		loff_t pos = page_offset(req->pages[0]) + num_read;

		fuse_read_update_size(inode, pos, req->misc.read.attr_ver);

	}



	fuse_invalidate_attr(req->pages[0]->mapping->host); /* atime changed */

	fuse_invalidate_attr(inode); /* atime changed */



	for (i = 0; i < req->num_pages; i++) {

		struct page *page = req->pages[i];
@@ -463,6 +502,7 @@ static void fuse_send_readpages(struct fuse_req *req, struct file *file, 
	size_t count = req->num_pages << PAGE_CACHE_SHIFT;

	req->out.page_zeroing = 1;

	fuse_read_fill(req, file, inode, pos, count, FUSE_READ);

	req->misc.read.attr_ver = fuse_get_attr_version(fc);

	if (fc->async_read) {

		struct fuse_file *ff = file->private_data;

		req->ff = fuse_file_get(ff);

fs/fuse/fuse_i.h

+6 −1
Original line number Diff line number Diff line
@@ -239,7 +239,10 @@ struct fuse_req { 
		} release;

		struct fuse_init_in init_in;

		struct fuse_init_out init_out;

		struct fuse_read_in read_in;

		struct {

			struct fuse_read_in in;

			u64 attr_ver;

		} read;

		struct {

			struct fuse_write_in in;

			struct fuse_write_out out;
@@ -637,3 +640,5 @@ void fuse_flush_writepages(struct inode *inode); 


void fuse_set_nowrite(struct inode *inode);

void fuse_release_nowrite(struct inode *inode);



u64 fuse_get_attr_version(struct fuse_conn *fc);

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