| Message ID | 1547862626-18425-1-git-send-email-pshilov@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | CIFS: Fix possible hang duing async MTU reads and writes | expand |
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 238b16d..82967f6 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -165,14 +165,14 @@ smb2_wait_mtu_credits(struct TCP_Server_Info *server, unsigned int size, scredits = server->credits; /* can deadlock with reopen */ - if (scredits == 1) { + if (scredits <= 8) { *num = SMB2_MAX_BUFFER_SIZE; *credits = 0; break; } - /* leave one credit for a possible reopen */ - scredits--; + /* leave some credits for reopen and other ops */ + scredits -= 8; *num = min_t(unsigned int, size, scredits * SMB2_MAX_BUFFER_SIZE);
When doing MTU i/o we need to leave some credits for possible reopen requests and other operations happening in parallel. Currently we leave 1 credit which is not enough even for reopen only: we need at least 2 credits if durable handle reconnect fails. Also there may be other operations at the same time including compounding ones which require 3 credits at a time each. Fix this by leaving 8 credits which is big enough to cover most scenarios. The proper fix would be to reconnect a file handle first and then obtain credits for an MTU request but this leads to bigger code changes and should happen in other patches. Cc: <stable@vger.kernel.org> Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com> --- fs/cifs/smb2ops.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)