[PATCH] cifs: fix credit accounting for extra channel

[Steve French]

With multichannel, operations like the queries
from "ls -lR" can cause all credits to be used and
errors to be returned since max_credits was not
being set correctly on the secondary channels and
thus the client was requesting 0 credits incorrectly
in some cases (which can lead to not having
enough credits to perform any operation on that
channel).

Signed-off-by: Aurelien Aptel <aaptel at suse.com>
CC: <stable at vger.kernel.org> # v5.8+
Reviewed-by: Shyam Prasad N <sprasad at microsoft.com>
Signed-off-by: Steve French <stfrench at microsoft.com>
---
 fs/cifs/connect.c | 10 +++++-----
 fs/cifs/sess.c    |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 112692300fb6..68642e3d4270 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1429,6 +1429,11 @@ cifs_get_tcp_session(struct smb3_fs_context *ctx)
  tcp_ses->min_offload = ctx->min_offload;
  tcp_ses->tcpStatus = CifsNeedNegotiate;

+ if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
+ tcp_ses->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
+ else
+ tcp_ses->max_credits = ctx->max_credits;
+
  tcp_ses->nr_targets = 1;
  tcp_ses->ignore_signature = ctx->ignore_signature;
  /* thread spawned, put it on the list */
@@ -2832,11 +2837,6 @@ static int mount_get_conns(struct
smb3_fs_context *ctx, struct cifs_sb_info *cif

  *nserver = server;

- if ((ctx->max_credits < 20) || (ctx->max_credits > 60000))
- server->max_credits = SMB2_MAX_CREDITS_AVAILABLE;
- else
- server->max_credits = ctx->max_credits;
-
  /* get a reference to a SMB session */
  ses = cifs_get_smb_ses(server, ctx);
  if (IS_ERR(ses)) {
diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 183a3a868d7b..63d517b9f2ff 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -230,6 +230,7 @@ cifs_ses_add_channel(struct cifs_sb_info *cifs_sb,
struct cifs_ses *ses,
  ctx.noautotune = ses->server->noautotune;
  ctx.sockopt_tcp_nodelay = ses->server->tcp_nodelay;
  ctx.echo_interval = ses->server->echo_interval / HZ;
+ ctx.max_credits = ses->server->max_credits;

  /*
  * This will be used for encoding/decoding user/domain/pw

-- 
Thanks,

Steve
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