6.18-stable review patch. If anyone has any objections, please let me know.
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From: David Howells dhowells@redhat.com
[ Upstream commit 9d85ac939d52e93d80efb01a299c6f0bedb30487 ]
If a DIO read or an unbuffered read request extends beyond the EOF, the server will return a short read and a status code indicating that EOF was hit, which gets translated to -ENODATA. Note that the client does not cap the request at i_size, but asks for the amount requested in case there's a race on the server with a third party.
Now, on the client side, the request will get split into multiple subrequests if rsize is smaller than the full request size. A subrequest that starts before or at the EOF and returns short data up to the EOF will be correctly handled, with the NETFS_SREQ_HIT_EOF flag being set, indicating to netfslib that we can't read more.
If a subrequest, however, starts after the EOF and not at it, HIT_EOF will not be flagged, its error will be set to -ENODATA and it will be abandoned. This will cause the request as a whole to fail with -ENODATA.
Fix this by setting NETFS_SREQ_HIT_EOF on any subrequest that lies beyond the EOF marker.
This can be reproduced by mounting with "cache=none,sign,vers=1.0" and doing a read of a file that's significantly bigger than the size of the file (e.g. attempting to read 64KiB from a 16KiB file).
Fixes: a68c74865f51 ("cifs: Fix SMB1 readv/writev callback in the same way as SMB2/3") Signed-off-by: David Howells dhowells@redhat.com Reviewed-by: Paulo Alcantara (Red Hat) pc@manguebit.org cc: Shyam Prasad N sprasad@microsoft.com cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/smb/client/cifssmb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/smb/client/cifssmb.c b/fs/smb/client/cifssmb.c index dcc50a2bfa4b2..bfc9b1ea76fac 100644 --- a/fs/smb/client/cifssmb.c +++ b/fs/smb/client/cifssmb.c @@ -1374,7 +1374,7 @@ cifs_readv_callback(struct mid_q_entry *mid) } else { size_t trans = rdata->subreq.transferred + rdata->got_bytes; if (trans < rdata->subreq.len && - rdata->subreq.start + trans == ictx->remote_i_size) { + rdata->subreq.start + trans >= ictx->remote_i_size) { rdata->result = 0; __set_bit(NETFS_SREQ_HIT_EOF, &rdata->subreq.flags); } else if (rdata->got_bytes > 0) {