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ceph: return the real size read when it hits EOF 

Currently, if the sync read handler ends up reading more from the last
object in the file than the i_size indicates, then it'll end up
returning the wrong length. Ensure that we cap the returned length and
pos at the EOF.

Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Xiubo Li 2021-10-30 13:16:40 +08:00 committed by Ilya Dryomov
parent 8cfc0c7ed3
commit c3d8e0b5de
1 changed files with 8 additions and 5 deletions
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13
fs/ceph/file.c
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@ -847,6 +847,7 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
ssize_t ret;
u64 off = iocb->ki_pos;
u64 len = iov_iter_count(to);
u64 i_size;
dout("sync_read on file %p %llu~%u %s\n", file, off, (unsigned)len,
(file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
@ -870,7 +871,6 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
struct page **pages;
int num_pages;
size_t page_off;
u64 i_size;
bool more;
int idx;
size_t left;
@ -953,11 +953,14 @@ static ssize_t ceph_sync_read(struct kiocb *iocb, struct iov_iter *to,
}
if (off > iocb->ki_pos) {
if (ret >= 0 &&
iov_iter_count(to) > 0 && off >= i_size_read(inode))
if (off >= i_size) {
*retry_op = CHECK_EOF;
ret = off - iocb->ki_pos;
iocb->ki_pos = off;
ret = i_size - iocb->ki_pos;
iocb->ki_pos = i_size;
} else {
ret = off - iocb->ki_pos;
iocb->ki_pos = off;
}
}
dout("sync_read result %zd retry_op %d\n", ret, *retry_op);