[patch 068/104] cifs: Fix cifs reconnection flags

Greg KH
2008-12-03T20:16:54Z

[-- Attachment #1: cifs-fix-cifs-reconnection-flags.patch --]
[-- Type: text/plain, Size: 18464 bytes --]

2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------
From: Steve French <sfrench@us.ibm.com>

commit 3b7952109361c684caf0c50474da8662ecc81019 upstream

[CIFS] Fix cifs reconnection flags

In preparation for Jeff's big umount/mount fixes to remove the possibility of
various races in cifs mount and linked list handling of sessions, sockets and
tree connections, this patch cleans up some repetitive code in cifs_mount,
and addresses a problem with ses->status and tcon->tidStatus in which we
were overloading the "need_reconnect" state with other status in that
field. So the "need_reconnect" flag has been broken out from those
two state fields (need reconnect was not mutually exclusive from some of the
other possible tid and ses states). In addition, a few exit cases in
cifs_mount were cleaned up, and a problem with a tcon flag (for lease support)
was not being set consistently for the 2nd mount of the same share

CC: Jeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/cifs/cifsfs.c | 2
fs/cifs/cifsglob.h | 5 +
fs/cifs/cifssmb.c | 40 ++++----
fs/cifs/connect.c | 252 ++++++++++++++++++++++++++---------------------------
fs/cifs/file.c | 2
5 files changed, 155 insertions(+), 146 deletions(-)

--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -967,7 +967,7 @@ static int cifs_oplock_thread(void *dumm
not bother sending an oplock release if session
to server still is disconnected since oplock
already released by the server in that case */
- if (pTcon->tidStatus != CifsNeedReconnect) {
+ if (!pTcon->need_reconnect) {
rc = CIFSSMBLock(0, pTcon, netfid,
0 /* len */ , 0 /* offset */, 0,
0, LOCKING_ANDX_OPLOCK_RELEASE,
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -122,6 +122,8 @@ struct cifs_cred {
*/

struct TCP_Server_Info {
+ struct list_head tcp_ses_list;
+ struct list_head smb_ses_list;
/* 15 character server name + 0x20 16th byte indicating type = srv */
char server_RFC1001_name[SERVER_NAME_LEN_WITH_NULL];
char unicode_server_Name[SERVER_NAME_LEN_WITH_NULL * 2];
@@ -195,6 +197,7 @@ struct cifsUidInfo {
*/
struct cifsSesInfo {
struct list_head cifsSessionList;
+ struct list_head tcon_list;
struct semaphore sesSem;
#if 0
struct cifsUidInfo *uidInfo; /* pointer to user info */
@@ -216,6 +219,7 @@ struct cifsSesInfo {
char userName[MAX_USERNAME_SIZE + 1];
char *domainName;
char *password;
+ bool need_reconnect:1; /* connection reset, uid now invalid */
};
/* no more than one of the following three session flags may be set */
#define CIFS_SES_NT4 1
@@ -287,6 +291,7 @@ struct cifsTconInfo {
bool seal:1; /* transport encryption for this mounted share */
bool unix_ext:1; /* if false disable Linux extensions to CIFS protocol
for this mount even if server would support */
+ bool need_reconnect:1; /* connection reset, tid now invalid */
/* BB add field for back pointer to sb struct(s)? */
};

--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -190,10 +190,10 @@ small_smb_init(int smb_command, int wct,
/* need to prevent multiple threads trying to
simultaneously reconnect the same SMB session */
down(&tcon->ses->sesSem);
- if (tcon->ses->status == CifsNeedReconnect)
+ if (tcon->ses->need_reconnect)
rc = cifs_setup_session(0, tcon->ses,
nls_codepage);
- if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
+ if (!rc && (tcon->need_reconnect)) {
mark_open_files_invalid(tcon);
rc = CIFSTCon(0, tcon->ses, tcon->treeName,
tcon, nls_codepage);
@@ -295,7 +295,7 @@ smb_init(int smb_command, int wct, struc
check for tcp and smb session status done differently
for those three - in the calling routine */
if (tcon) {
- if (tcon->tidStatus == CifsExiting) {
+ if (tcon->need_reconnect) {
/* only tree disconnect, open, and write,
(and ulogoff which does not have tcon)
are allowed as we start force umount */
@@ -337,10 +337,10 @@ smb_init(int smb_command, int wct, struc
/* need to prevent multiple threads trying to
simultaneously reconnect the same SMB session */
down(&tcon->ses->sesSem);
- if (tcon->ses->status == CifsNeedReconnect)
+ if (tcon->ses->need_reconnect)
rc = cifs_setup_session(0, tcon->ses,
nls_codepage);
- if (!rc && (tcon->tidStatus == CifsNeedReconnect)) {
+ if (!rc && (tcon->need_reconnect)) {
mark_open_files_invalid(tcon);
rc = CIFSTCon(0, tcon->ses, tcon->treeName,
tcon, nls_codepage);
@@ -759,7 +759,7 @@ CIFSSMBTDis(const int xid, struct cifsTc

/* No need to return error on this operation if tid invalidated and
closed on server already e.g. due to tcp session crashing */
- if (tcon->tidStatus == CifsNeedReconnect) {
+ if (tcon->need_reconnect) {
up(&tcon->tconSem);
return 0;
}
@@ -806,32 +806,36 @@ CIFSSMBLogoff(const int xid, struct cifs
up(&ses->sesSem);
return -EBUSY;
}
+
+ if (ses->server == NULL)
+ return -EIO;
+
+ if (ses->need_reconnect)
+ goto session_already_dead; /* no need to send SMBlogoff if uid
+ already closed due to reconnect */
rc = small_smb_init(SMB_COM_LOGOFF_ANDX, 2, NULL, (void **)&pSMB);
if (rc) {
up(&ses->sesSem);
return rc;
}

- if (ses->server) {
- pSMB->hdr.Mid = GetNextMid(ses->server);
+ pSMB->hdr.Mid = GetNextMid(ses->server);

- if (ses->server->secMode &
+ if (ses->server->secMode &
(SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED))
pSMB->hdr.Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
- }

pSMB->hdr.Uid = ses->Suid;

pSMB->AndXCommand = 0xFF;
rc = SendReceiveNoRsp(xid, ses, (struct smb_hdr *) pSMB, 0);
- if (ses->server) {
- atomic_dec(&ses->server->socketUseCount);
- if (atomic_read(&ses->server->socketUseCount) == 0) {
- spin_lock(&GlobalMid_Lock);
- ses->server->tcpStatus = CifsExiting;
- spin_unlock(&GlobalMid_Lock);
- rc = -ESHUTDOWN;
- }
+session_already_dead:
+ atomic_dec(&ses->server->socketUseCount);
+ if (atomic_read(&ses->server->socketUseCount) == 0) {
+ spin_lock(&GlobalMid_Lock);
+ ses->server->tcpStatus = CifsExiting;
+ spin_unlock(&GlobalMid_Lock);
+ rc = -ESHUTDOWN;
}
up(&ses->sesSem);

--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -147,7 +147,7 @@ cifs_reconnect(struct TCP_Server_Info *s
ses = list_entry(tmp, struct cifsSesInfo, cifsSessionList);
if (ses->server) {
if (ses->server == server) {
- ses->status = CifsNeedReconnect;
+ ses->need_reconnect = true;
ses->ipc_tid = 0;
}
}
@@ -156,7 +156,7 @@ cifs_reconnect(struct TCP_Server_Info *s
list_for_each(tmp, &GlobalTreeConnectionList) {
tcon = list_entry(tmp, struct cifsTconInfo, cifsConnectionList);
if ((tcon->ses) && (tcon->ses->server == server))
- tcon->tidStatus = CifsNeedReconnect;
+ tcon->need_reconnect = true;
}
read_unlock(&GlobalSMBSeslock);
/* do not want to be sending data on a socket we are freeing */
@@ -1868,6 +1868,92 @@ convert_delimiter(char *path, char delim
}
}

+static void setup_cifs_sb(struct smb_vol *pvolume_info,
+ struct cifs_sb_info *cifs_sb)
+{
+ if (pvolume_info->rsize > CIFSMaxBufSize) {
+ cERROR(1, ("rsize %d too large, using MaxBufSize",
+ pvolume_info->rsize));
+ cifs_sb->rsize = CIFSMaxBufSize;
+ } else if ((pvolume_info->rsize) &&
+ (pvolume_info->rsize <= CIFSMaxBufSize))
+ cifs_sb->rsize = pvolume_info->rsize;
+ else /* default */
+ cifs_sb->rsize = CIFSMaxBufSize;
+
+ if (pvolume_info->wsize > PAGEVEC_SIZE * PAGE_CACHE_SIZE) {
+ cERROR(1, ("wsize %d too large, using 4096 instead",
+ pvolume_info->wsize));
+ cifs_sb->wsize = 4096;
+ } else if (pvolume_info->wsize)
+ cifs_sb->wsize = pvolume_info->wsize;
+ else
+ cifs_sb->wsize = min_t(const int,
+ PAGEVEC_SIZE * PAGE_CACHE_SIZE,
+ 127*1024);
+ /* old default of CIFSMaxBufSize was too small now
+ that SMB Write2 can send multiple pages in kvec.
+ RFC1001 does not describe what happens when frame
+ bigger than 128K is sent so use that as max in
+ conjunction with 52K kvec constraint on arch with 4K
+ page size */
+
+ if (cifs_sb->rsize < 2048) {
+ cifs_sb->rsize = 2048;
+ /* Windows ME may prefer this */
+ cFYI(1, ("readsize set to minimum: 2048"));
+ }
+ /* calculate prepath */
+ cifs_sb->prepath = pvolume_info->prepath;
+ if (cifs_sb->prepath) {
+ cifs_sb->prepathlen = strlen(cifs_sb->prepath);
+ /* we can not convert the / to \ in the path
+ separators in the prefixpath yet because we do not
+ know (until reset_cifs_unix_caps is called later)
+ whether POSIX PATH CAP is available. We normalize
+ the / to \ after reset_cifs_unix_caps is called */
+ pvolume_info->prepath = NULL;
+ } else
+ cifs_sb->prepathlen = 0;
+ cifs_sb->mnt_uid = pvolume_info->linux_uid;
+ cifs_sb->mnt_gid = pvolume_info->linux_gid;
+ cifs_sb->mnt_file_mode = pvolume_info->file_mode;
+ cifs_sb->mnt_dir_mode = pvolume_info->dir_mode;
+ cFYI(1, ("file mode: 0x%x dir mode: 0x%x",
+ cifs_sb->mnt_file_mode, cifs_sb->mnt_dir_mode));
+
+ if (pvolume_info->noperm)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_PERM;
+ if (pvolume_info->setuids)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
+ if (pvolume_info->server_ino)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
+ if (pvolume_info->remap)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SPECIAL_CHR;
+ if (pvolume_info->no_xattr)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_XATTR;
+ if (pvolume_info->sfu_emul)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;
+ if (pvolume_info->nobrl)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
+ if (pvolume_info->cifs_acl)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
+ if (pvolume_info->override_uid)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
+ if (pvolume_info->override_gid)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
+ if (pvolume_info->dynperm)
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DYNPERM;
+ if (pvolume_info->direct_io) {
+ cFYI(1, ("mounting share using direct i/o"));
+ cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
+ }
+
+ if ((pvolume_info->cifs_acl) && (pvolume_info->dynperm))
+ cERROR(1, ("mount option dynperm ignored if cifsacl "
+ "mount option supported"));
+}
+
int
cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
char *mount_data, const char *devname)
@@ -1973,9 +2059,7 @@ cifs_mount(struct super_block *sb, struc
goto out;
}

- if (srvTcp) {
- cFYI(1, ("Existing tcp session with server found"));
- } else { /* create socket */
+ if (!srvTcp) { /* create socket */
if (volume_info.port)
sin_server.sin_port = htons(volume_info.port);
else
@@ -2051,7 +2135,7 @@ cifs_mount(struct super_block *sb, struc
cFYI(1, ("Existing smb sess found (status=%d)",
pSesInfo->status));
down(&pSesInfo->sesSem);
- if (pSesInfo->status == CifsNeedReconnect) {
+ if (pSesInfo->need_reconnect) {
cFYI(1, ("Session needs reconnect"));
rc = cifs_setup_session(xid, pSesInfo,
cifs_sb->local_nls);
@@ -2101,139 +2185,52 @@ cifs_mount(struct super_block *sb, struc

/* search for existing tcon to this server share */
if (!rc) {
- if (volume_info.rsize > CIFSMaxBufSize) {
- cERROR(1, ("rsize %d too large, using MaxBufSize",
- volume_info.rsize));
- cifs_sb->rsize = CIFSMaxBufSize;
- } else if ((volume_info.rsize) &&
- (volume_info.rsize <= CIFSMaxBufSize))
- cifs_sb->rsize = volume_info.rsize;
- else /* default */
- cifs_sb->rsize = CIFSMaxBufSize;
-
- if (volume_info.wsize > PAGEVEC_SIZE * PAGE_CACHE_SIZE) {
- cERROR(1, ("wsize %d too large, using 4096 instead",
- volume_info.wsize));
- cifs_sb->wsize = 4096;
- } else if (volume_info.wsize)
- cifs_sb->wsize = volume_info.wsize;
- else
- cifs_sb->wsize =
- min_t(const int, PAGEVEC_SIZE * PAGE_CACHE_SIZE,
- 127*1024);
- /* old default of CIFSMaxBufSize was too small now
- that SMB Write2 can send multiple pages in kvec.
- RFC1001 does not describe what happens when frame
- bigger than 128K is sent so use that as max in
- conjunction with 52K kvec constraint on arch with 4K
- page size */
-
- if (cifs_sb->rsize < 2048) {
- cifs_sb->rsize = 2048;
- /* Windows ME may prefer this */
- cFYI(1, ("readsize set to minimum: 2048"));
- }
- /* calculate prepath */
- cifs_sb->prepath = volume_info.prepath;
- if (cifs_sb->prepath) {
- cifs_sb->prepathlen = strlen(cifs_sb->prepath);
- /* we can not convert the / to \ in the path
- separators in the prefixpath yet because we do not
- know (until reset_cifs_unix_caps is called later)
- whether POSIX PATH CAP is available. We normalize
- the / to \ after reset_cifs_unix_caps is called */
- volume_info.prepath = NULL;
- } else
- cifs_sb->prepathlen = 0;
- cifs_sb->mnt_uid = volume_info.linux_uid;
- cifs_sb->mnt_gid = volume_info.linux_gid;
- cifs_sb->mnt_file_mode = volume_info.file_mode;
- cifs_sb->mnt_dir_mode = volume_info.dir_mode;
- cFYI(1, ("file mode: 0x%x dir mode: 0x%x",
- cifs_sb->mnt_file_mode, cifs_sb->mnt_dir_mode));
-
- if (volume_info.noperm)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_PERM;
- if (volume_info.setuids)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SET_UID;
- if (volume_info.server_ino)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_SERVER_INUM;
- if (volume_info.remap)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_MAP_SPECIAL_CHR;
- if (volume_info.no_xattr)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_XATTR;
- if (volume_info.sfu_emul)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_UNX_EMUL;
- if (volume_info.nobrl)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_NO_BRL;
- if (volume_info.cifs_acl)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_CIFS_ACL;
- if (volume_info.override_uid)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_UID;
- if (volume_info.override_gid)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_OVERR_GID;
- if (volume_info.dynperm)
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DYNPERM;
- if (volume_info.direct_io) {
- cFYI(1, ("mounting share using direct i/o"));
- cifs_sb->mnt_cifs_flags |= CIFS_MOUNT_DIRECT_IO;
- }
-
- if ((volume_info.cifs_acl) && (volume_info.dynperm))
- cERROR(1, ("mount option dynperm ignored if cifsacl "
- "mount option supported"));
-
+ setup_cifs_sb(&volume_info, cifs_sb);
tcon =
find_unc(sin_server.sin_addr.s_addr, volume_info.UNC,
volume_info.username);
if (tcon) {
cFYI(1, ("Found match on UNC path"));
- /* we can have only one retry value for a connection
- to a share so for resources mounted more than once
- to the same server share the last value passed in
- for the retry flag is used */
- tcon->retry = volume_info.retry;
- tcon->nocase = volume_info.nocase;
if (tcon->seal != volume_info.seal)
cERROR(1, ("transport encryption setting "
"conflicts with existing tid"));
} else {
tcon = tconInfoAlloc();
- if (tcon == NULL)
+ if (tcon == NULL) {
rc = -ENOMEM;
- else {
- /* check for null share name ie connecting to
- * dfs root */
-
- /* BB check if this works for exactly length
- * three strings */
- if ((strchr(volume_info.UNC + 3, '\\') == NULL)
- && (strchr(volume_info.UNC + 3, '/') ==
- NULL)) {
-/* rc = connect_to_dfs_path(xid, pSesInfo,
- "", cifs_sb->local_nls,
- cifs_sb->mnt_cifs_flags &
- CIFS_MOUNT_MAP_SPECIAL_CHR);*/
- cFYI(1, ("DFS root not supported"));
- rc = -ENODEV;
- goto out;
- } else {
- /* BB Do we need to wrap sesSem around
- * this TCon call and Unix SetFS as
- * we do on SessSetup and reconnect? */
- rc = CIFSTCon(xid, pSesInfo,
- volume_info.UNC,
- tcon, cifs_sb->local_nls);
- cFYI(1, ("CIFS Tcon rc = %d", rc));
- }
- if (!rc) {
- atomic_inc(&pSesInfo->inUse);
- tcon->retry = volume_info.retry;
- tcon->nocase = volume_info.nocase;
- tcon->seal = volume_info.seal;
- }
+ goto mount_fail_check;
}
+
+ /* check for null share name ie connect to dfs root */
+
+ /* BB check if works for exactly length 3 strings */
+ if ((strchr(volume_info.UNC + 3, '\\') == NULL)
+ && (strchr(volume_info.UNC + 3, '/') == NULL)) {
+ /* rc = connect_to_dfs_path(...) */
+ cFYI(1, ("DFS root not supported"));
+ rc = -ENODEV;
+ goto mount_fail_check;
+ } else {
+ /* BB Do we need to wrap sesSem around
+ * this TCon call and Unix SetFS as
+ * we do on SessSetup and reconnect? */
+ rc = CIFSTCon(xid, pSesInfo, volume_info.UNC,
+ tcon, cifs_sb->local_nls);
+ cFYI(1, ("CIFS Tcon rc = %d", rc));
+ }
+ if (!rc) {
+ atomic_inc(&pSesInfo->inUse);
+ tcon->seal = volume_info.seal;
+ } else
+ goto mount_fail_check;
}
+
+ /* we can have only one retry value for a connection
+ to a share so for resources mounted more than once
+ to the same server share the last value passed in
+ for the retry flag is used */
+ tcon->retry = volume_info.retry;
+ tcon->nocase = volume_info.nocase;
}
if (pSesInfo) {
if (pSesInfo->capabilities & CAP_LARGE_FILES) {
@@ -2246,6 +2243,7 @@ cifs_mount(struct super_block *sb, struc
sb->s_time_gran = 100;

/* on error free sesinfo and tcon struct if needed */
+mount_fail_check:
if (rc) {
/* if session setup failed, use count is zero but
we still need to free cifsd thread */
@@ -3499,6 +3497,7 @@ CIFSTCon(unsigned int xid, struct cifsSe
/* above now done in SendReceive */
if ((rc == 0) && (tcon != NULL)) {
tcon->tidStatus = CifsGood;
+ tcon->need_reconnect = false;
tcon->tid = smb_buffer_response->Tid;
bcc_ptr = pByteArea(smb_buffer_response);
length = strnlen(bcc_ptr, BCC(smb_buffer_response) - 2);
@@ -3730,6 +3729,7 @@ int cifs_setup_session(unsigned int xid,
} else {
cFYI(1, ("CIFS Session Established successfully"));
pSesInfo->status = CifsGood;
+ pSesInfo->need_reconnect = false;
}

ss_err_exit:
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -493,7 +493,7 @@ int cifs_close(struct inode *inode, stru
if (pTcon) {
/* no sense reconnecting to close a file that is
already closed */
- if (pTcon->tidStatus != CifsNeedReconnect) {
+ if (!pTcon->need_reconnect) {
timeout = 2;
while ((atomic_read(&pSMBFile->wrtPending) != 0)
&& (timeout <= 2048)) {