[PATCH AUTOSEL 5.7 245/388] fuse: fix copy_file_range cache issues

Sasha Levin
2020-06-18T02:38:21Z

From: Miklos Szeredi <mszeredi@redhat.com>

[ Upstream commit 2c4656dfd994538176db30ce09c02cc0dfc361ae ]

a) Dirty cache needs to be written back not just in the writeback_cache
case, since the dirty pages may come from memory maps.

b) The fuse_writeback_range() helper takes an inclusive interval, so the
end position needs to be pos+len-1 instead of pos+len.

Fixes: 88bc7d5097a1 ("fuse: add support for copy_file_range()")
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/fuse/file.c | 20 ++++++++------------
1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index d400b71b98d5..d58324198b7a 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -3280,13 +3280,11 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
return -EXDEV;

- if (fc->writeback_cache) {
- inode_lock(inode_in);
- err = fuse_writeback_range(inode_in, pos_in, pos_in + len);
- inode_unlock(inode_in);
- if (err)
- return err;
- }
+ inode_lock(inode_in);
+ err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1);
+ inode_unlock(inode_in);
+ if (err)
+ return err;

inode_lock(inode_out);

@@ -3294,11 +3292,9 @@ static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in,
if (err)
goto out;

- if (fc->writeback_cache) {
- err = fuse_writeback_range(inode_out, pos_out, pos_out + len);
- if (err)
- goto out;
- }
+ err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1);
+ if (err)
+ goto out;

if (is_unstable)
set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state);
--
2.25.1