cachefiles: Fix missing pos updates in cachefiles_ondemand_fd_write_iter()

[ Upstream commit 56f4856b425a30e1d8b3e41e6cde8bfba90ba5f8 ]

In the erofs on-demand loading scenario, read and write operations are
usually delivered through "off" and "len" contained in read req in user
mode. Naturally, pwrite is used to specify a specific offset to complete
write operations.

However, if the write(not pwrite) syscall is called multiple times in the
read-ahead scenario, we need to manually update ki_pos after each write
operation to update file->f_pos.

This step is currently missing from the cachefiles_ondemand_fd_write_iter
function, added to address this issue.

Fixes: c838305450 ("cachefiles: notify the user daemon when looking up cookie")
Signed-off-by: Zizhi Wo <wozizhi@huawei.com>
Link: https://lore.kernel.org/r/20241107110649.3980193-3-wozizhi@huawei.com
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zizhi Wo 2024-11-07 19:06:46 +08:00 committed by Greg Kroah-Hartman
parent 01f605a4cd
commit ae8c963906
1 changed files with 3 additions and 1 deletions

View File

@ -78,8 +78,10 @@ static ssize_t cachefiles_ondemand_fd_write_iter(struct kiocb *kiocb,
trace_cachefiles_ondemand_fd_write(object, file_inode(file), pos, len);
ret = __cachefiles_write(object, file, pos, iter, NULL, NULL);
if (!ret)
if (!ret) {
ret = len;
kiocb->ki_pos += ret;
}
return ret;
}