[PATCH] CIFS: Indicate reconnect with a parm in read_into

Discussion:

[PATCH] CIFS: Indicate reconnect with a parm in read_into_pages

Pavel Shilovsky

2014-07-09 12:48:47 UTC

that lets us not mix EAGAIN error code with reconnect and
prevent possible errors further.

Signed-off-by: Pavel Shilovsky <pshilovsky-***@public.gmane.org>
---
fs/cifs/cifsglob.h | 2 +-
fs/cifs/cifsproto.h | 2 +-
fs/cifs/cifssmb.c | 11 ++++++++---
fs/cifs/connect.c | 11 +++++++++--
fs/cifs/file.c | 16 ++++++++++------
5 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index f33ff4c..f57e5bc 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1064,7 +1064,7 @@ struct cifs_readdata {
struct work_struct work;
int (*read_into_pages)(struct TCP_Server_Info *server,
struct cifs_readdata *rdata,
- unsigned int len);
+ unsigned int len, bool *was_reconnect);
struct kvec iov;
unsigned int pagesz;
unsigned int tailsz;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index c31ce98..8e4f826 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -184,7 +184,7 @@ extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
unsigned int to_read);
extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
struct kvec *iov_orig, unsigned int nr_segs,
- unsigned int to_read);
+ unsigned int to_read, bool *was_reconnect);
extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
struct cifs_sb_info *cifs_sb);
extern int cifs_match_super(struct super_block *, void *);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index e411d2e..6697b78 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1425,6 +1425,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
struct cifs_readdata *rdata = mid->callback_data;
char *buf = server->smallbuf;
unsigned int buflen = get_rfc1002_length(buf) + 4;
+ bool was_reconnect;

cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n",
__func__, mid->mid, rdata->offset, rdata->bytes);
@@ -1440,7 +1441,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
rdata->iov.iov_base = buf + HEADER_SIZE(server) - 1;
rdata->iov.iov_len = len;

- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_readv_from_socket(server, &rdata->iov, 1, len, NULL);
if (length < 0)
return length;
server->total_read += length;
@@ -1488,7 +1489,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
/* read any junk before data into the rest of smallbuf */
rdata->iov.iov_base = buf + server->total_read;
rdata->iov.iov_len = len;
- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_readv_from_socket(server, &rdata->iov, 1, len,
+ NULL);
if (length < 0)
return length;
server->total_read += length;
@@ -1508,7 +1510,10 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
return cifs_readv_discard(server, mid);
}

- length = rdata->read_into_pages(server, rdata, data_len);
+ length = rdata->read_into_pages(server, rdata, data_len,
+ &was_reconnect);
+ if (was_reconnect)
+ return -EAGAIN;
if (length < 0)
return length;

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 20d75b8..f6a8107 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -538,13 +538,15 @@ get_server_iovec(struct TCP_Server_Info *server, unsigned int nr_segs)

int
cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
- unsigned int nr_segs, unsigned int to_read)
+ unsigned int nr_segs, unsigned int to_read,
+ bool *was_reconnect)
{
int length = 0;
int total_read;
unsigned int segs;
struct msghdr smb_msg;
struct kvec *iov;
+ bool rec = false;

iov = get_server_iovec(server, nr_segs);
if (!iov)
@@ -557,6 +559,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
try_to_freeze();

if (server_unresponsive(server)) {
+ rec = true;
total_read = -EAGAIN;
break;
}
@@ -571,6 +574,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
break;
} else if (server->tcpStatus == CifsNeedReconnect) {
cifs_reconnect(server);
+ rec = true;
total_read = -EAGAIN;
break;
} else if (length == -ERESTARTSYS ||
@@ -588,10 +592,13 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
cifs_dbg(FYI, "Received no data or error: expecting %d\n"
"got %d", to_read, length);
cifs_reconnect(server);
+ rec = true;
total_read = -EAGAIN;
break;
}
}
+ if (was_reconnect)
+ *was_reconnect = rec;
return total_read;
}

@@ -604,7 +611,7 @@ cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
iov.iov_base = buf;
iov.iov_len = to_read;

- return cifs_readv_from_socket(server, &iov, 1, to_read);
+ return cifs_readv_from_socket(server, &iov, 1, to_read, NULL);
}

static bool
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index d5f66ba..d7f5742 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2865,7 +2865,8 @@ cifs_uncached_readv_complete(struct work_struct *work)

static int
cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
+ struct cifs_readdata *rdata, unsigned int len,
+ bool *was_reconnect)
{
int total_read = 0, result = 0;
unsigned int i;
@@ -2900,7 +2901,8 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
continue;
}

- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+ result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len,
+ was_reconnect);
kunmap(page);
if (result < 0)
break;
@@ -2908,7 +2910,7 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
total_read += result;
}

- return total_read > 0 && result != -EAGAIN ? total_read : result;
+ return total_read > 0 ? total_read : result;
}

static int
@@ -3287,7 +3289,8 @@ cifs_readv_complete(struct work_struct *work)

static int
cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
+ struct cifs_readdata *rdata, unsigned int len,
+ bool *was_reconnect)
{
int total_read = 0, result = 0;
unsigned int i;
@@ -3350,7 +3353,8 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
continue;
}

- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+ result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len,
+ was_reconnect);
kunmap(page);
if (result < 0)
break;
@@ -3358,7 +3362,7 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
total_read += result;
}

- return total_read > 0 && result != -EAGAIN ? total_read : result;
+ return total_read > 0 ? total_read : result;
}

static int

--
1.8.1.2

Jeff Layton

2014-07-09 13:07:19 UTC

Permalink

On Wed, 9 Jul 2014 16:48:47 +0400

Post by Pavel Shilovsky
that lets us not mix EAGAIN error code with reconnect and
prevent possible errors further.
---
fs/cifs/cifsglob.h | 2 +-
fs/cifs/cifsproto.h | 2 +-
fs/cifs/cifssmb.c | 11 ++++++++---
fs/cifs/connect.c | 11 +++++++++--
fs/cifs/file.c | 16 ++++++++++------
5 files changed, 29 insertions(+), 13 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index f33ff4c..f57e5bc 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1064,7 +1064,7 @@ struct cifs_readdata {
struct work_struct work;
int (*read_into_pages)(struct TCP_Server_Info *server,
struct cifs_readdata *rdata,
- unsigned int len);
+ unsigned int len, bool *was_reconnect);
struct kvec iov;
unsigned int pagesz;
unsigned int tailsz;
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index c31ce98..8e4f826 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -184,7 +184,7 @@ extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
unsigned int to_read);
extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
struct kvec *iov_orig, unsigned int nr_segs,
- unsigned int to_read);
+ unsigned int to_read, bool *was_reconnect);
extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
struct cifs_sb_info *cifs_sb);
extern int cifs_match_super(struct super_block *, void *);
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index e411d2e..6697b78 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1425,6 +1425,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
struct cifs_readdata *rdata = mid->callback_data;
char *buf = server->smallbuf;
unsigned int buflen = get_rfc1002_length(buf) + 4;
+ bool was_reconnect;
cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n",
__func__, mid->mid, rdata->offset, rdata->bytes);
@@ -1440,7 +1441,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
rdata->iov.iov_base = buf + HEADER_SIZE(server) - 1;
rdata->iov.iov_len = len;
- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_readv_from_socket(server, &rdata->iov, 1, len, NULL);
if (length < 0)
return length;
server->total_read += length;
@@ -1488,7 +1489,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
/* read any junk before data into the rest of smallbuf */
rdata->iov.iov_base = buf + server->total_read;
rdata->iov.iov_len = len;
- length = cifs_readv_from_socket(server, &rdata->iov, 1, len);
+ length = cifs_readv_from_socket(server, &rdata->iov, 1, len,
+ NULL);
if (length < 0)
return length;
server->total_read += length;
@@ -1508,7 +1510,10 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
return cifs_readv_discard(server, mid);
}
- length = rdata->read_into_pages(server, rdata, data_len);
+ length = rdata->read_into_pages(server, rdata, data_len,
+ &was_reconnect);
+ if (was_reconnect)
+ return -EAGAIN;
if (length < 0)
return length;
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 20d75b8..f6a8107 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -538,13 +538,15 @@ get_server_iovec(struct TCP_Server_Info *server, unsigned int nr_segs)
int
cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
- unsigned int nr_segs, unsigned int to_read)
+ unsigned int nr_segs, unsigned int to_read,
+ bool *was_reconnect)
{
int length = 0;
int total_read;
unsigned int segs;
struct msghdr smb_msg;
struct kvec *iov;
+ bool rec = false;
iov = get_server_iovec(server, nr_segs);
if (!iov)
@@ -557,6 +559,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
try_to_freeze();
if (server_unresponsive(server)) {
+ rec = true;
total_read = -EAGAIN;
break;
}
@@ -571,6 +574,7 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
break;
} else if (server->tcpStatus == CifsNeedReconnect) {
cifs_reconnect(server);
+ rec = true;
total_read = -EAGAIN;
break;
} else if (length == -ERESTARTSYS ||
@@ -588,10 +592,13 @@ cifs_readv_from_socket(struct TCP_Server_Info *server, struct kvec *iov_orig,
cifs_dbg(FYI, "Received no data or error: expecting %d\n"
"got %d", to_read, length);
cifs_reconnect(server);
+ rec = true;
total_read = -EAGAIN;
break;
}
}
+ if (was_reconnect)
+ *was_reconnect = rec;
return total_read;
}
@@ -604,7 +611,7 @@ cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
iov.iov_base = buf;
iov.iov_len = to_read;
- return cifs_readv_from_socket(server, &iov, 1, to_read);
+ return cifs_readv_from_socket(server, &iov, 1, to_read, NULL);
}
static bool
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index d5f66ba..d7f5742 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2865,7 +2865,8 @@ cifs_uncached_readv_complete(struct work_struct *work)
static int
cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
+ struct cifs_readdata *rdata, unsigned int len,
+ bool *was_reconnect)
{
int total_read = 0, result = 0;
unsigned int i;
@@ -2900,7 +2901,8 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
continue;
}
- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+ result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len,
+ was_reconnect);
kunmap(page);
if (result < 0)
break;
@@ -2908,7 +2910,7 @@ cifs_uncached_read_into_pages(struct TCP_Server_Info *server,
total_read += result;
}
- return total_read > 0 && result != -EAGAIN ? total_read : result;
+ return total_read > 0 ? total_read : result;
}
static int
@@ -3287,7 +3289,8 @@ cifs_readv_complete(struct work_struct *work)
static int
cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
- struct cifs_readdata *rdata, unsigned int len)
+ struct cifs_readdata *rdata, unsigned int len,
+ bool *was_reconnect)
{
int total_read = 0, result = 0;
unsigned int i;
@@ -3350,7 +3353,8 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
continue;
}
- result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len);
+ result = cifs_readv_from_socket(server, &iov, 1, iov.iov_len,
+ was_reconnect);
kunmap(page);
if (result < 0)
break;
@@ -3358,7 +3362,7 @@ cifs_readpages_read_into_pages(struct TCP_Server_Info *server,
total_read += result;
}
- return total_read > 0 && result != -EAGAIN ? total_read : result;
+ return total_read > 0 ? total_read : result;
}
static int

Ugh.

It seems like we ought to instead just designate a different error code
than -EAGAIN (-ECONNABORTED?) for the case where a reconnect is needed,
and fix up the callers to handle that appropriately. There aren't that
many callers of cifs_readv_from_socket...

--
Jeff Layton <jlayton-***@public.gmane.org>

Pavel Shilovsky

2014-07-10 09:48:38 UTC

Permalink

Post by Jeff Layton
On Wed, 9 Jul 2014 16:48:47 +0400

Ugh.
It seems like we ought to instead just designate a different error code
than -EAGAIN (-ECONNABORTED?) for the case where a reconnect is needed,
and fix up the callers to handle that appropriately. There aren't that
many callers of cifs_readv_from_socket...

Agree. I've created the series that uses this new error code. It also
uses a short read data (got before reconnect) to fill the output
buffer and prevents the issue you described before: when we retry a
partially received request and got non-retry error, we loose the
received data.

--
Best regards,
Pavel Shilovsky.