On 11/1/21 7:58 PM, Jeff Layton wrote:
On Sat, 2021-10-30 at 13:16 +0800, xiubli@xxxxxxxxxx wrote:
From: Xiubo Li <xiubli@xxxxxxxxxx>
Currently, if we end up reading more from the last object in the file
than the i_size indicates then we'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@xxxxxxxxxx>
---
Changed in V4:
- move the i_size_read() into the while loop and use the lastest i_size
read to do the check at the end of ceph_sync_read().
fs/ceph/file.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 91173d3aa161..6005b430f6f7 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -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);
Thanks, looks good. I dropped the two patches I had merged for this on
Friday and merged this one instead.
Cool, thanks.
