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Commit a3a53b76 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

cifs: Add support for failover in smb2_reconnect() 



After a successful failover in cifs_reconnect(), the smb2_reconnect()
function will make sure to reconnect every tcon to new target server.

For SMB2+.

Signed-off-by: default avatarPaulo Alcantara <palcantara@suse.de>
Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 23324407

fs/cifs/cifsproto.h

+2 −0
Original line number Diff line number Diff line
@@ -565,6 +565,8 @@ void cifs_free_hash(struct crypto_shash **shash, struct sdesc **sdesc); 
extern void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page,

				unsigned int *len, unsigned int *offset);



void extract_unc_hostname(const char *unc, const char **h, size_t *len);



#ifdef CONFIG_CIFS_DFS_UPCALL

static inline int get_dfs_path(const unsigned int xid, struct cifs_ses *ses,

			       const char *old_path,

fs/cifs/misc.c

+17 −0
Original line number Diff line number Diff line
@@ -952,3 +952,20 @@ void rqst_page_get_length(struct smb_rqst *rqst, unsigned int page, 
	else if (page == 0)

		*len = rqst->rq_pagesz - rqst->rq_offset;

}



void extract_unc_hostname(const char *unc, const char **h, size_t *len)

{

	const char *end;



	/* skip initial slashes */

	while (*unc && (*unc == '\\' || *unc == '/'))

		unc++;



	end = unc;



	while (*end && !(*end == '\\' || *end == '/'))

		end++;



	*h = unc;

	*len = end - unc;

}

fs/cifs/smb2pdu.c

+85 −3
Original line number Diff line number Diff line
@@ -50,6 +50,9 @@ 
#include "cifs_spnego.h"

#include "smbdirect.h"

#include "trace.h"

#ifdef CONFIG_CIFS_DFS_UPCALL

#include "dfs_cache.h"

#endif



/*

 *  The following table defines the expected "StructureSize" of SMB2 requests
@@ -152,6 +155,77 @@ smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd, 
	return;

}



#ifdef CONFIG_CIFS_DFS_UPCALL

static int __smb2_reconnect(const struct nls_table *nlsc,

			    struct cifs_tcon *tcon)

{

	int rc;

	struct dfs_cache_tgt_list tl;

	struct dfs_cache_tgt_iterator *it = NULL;

	char tree[MAX_TREE_SIZE + 1];

	const char *tcp_host;

	size_t tcp_host_len;

	const char *dfs_host;

	size_t dfs_host_len;



	if (tcon->ipc) {

		snprintf(tree, sizeof(tree), "\\\\%s\\IPC$",

			 tcon->ses->server->hostname);

		return SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);

	}



	if (!tcon->dfs_path)

		return SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);



	rc = dfs_cache_noreq_find(tcon->dfs_path + 1, NULL, &tl);

	if (rc)

		return rc;



	extract_unc_hostname(tcon->ses->server->hostname, &tcp_host,

			     &tcp_host_len);



	for (it = dfs_cache_get_tgt_iterator(&tl); it;

	     it = dfs_cache_get_next_tgt(&tl, it)) {

		const char *tgt = dfs_cache_get_tgt_name(it);



		extract_unc_hostname(tgt, &dfs_host, &dfs_host_len);



		if (dfs_host_len != tcp_host_len

		    || strncasecmp(dfs_host, tcp_host, dfs_host_len) != 0) {

			cifs_dbg(FYI, "%s: skipping %.*s, doesn't match %.*s",

				 __func__,

				 (int)dfs_host_len, dfs_host,

				 (int)tcp_host_len, tcp_host);

			continue;

		}



		snprintf(tree, sizeof(tree), "\\%s", tgt);



		rc = SMB2_tcon(0, tcon->ses, tree, tcon, nlsc);

		if (!rc)

			break;

		if (rc == -EREMOTE)

			break;

	}



	if (!rc) {

		if (it)

			rc = dfs_cache_noreq_update_tgthint(tcon->dfs_path + 1,

							    it);

		else

			rc = -ENOENT;

	}

	dfs_cache_free_tgts(&tl);

	return rc;

}

#else

static inline int __smb2_reconnect(const struct nls_table *nlsc,

				   struct cifs_tcon *tcon)

{

	return SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nlsc);

}

#endif



static int

smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)

{
@@ -159,6 +233,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) 
	struct nls_table *nls_codepage;

	struct cifs_ses *ses;

	struct TCP_Server_Info *server;

	int retries;



	/*

	 * SMB2s NegProt, SessSetup, Logoff do not have tcon yet so
@@ -192,9 +267,12 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) 
	ses = tcon->ses;

	server = ses->server;



	retries = server->nr_targets;



	/*

	 * Give demultiplex thread up to 10 seconds to reconnect, should be

	 * greater than cifs socket timeout which is 7 seconds

	 * Give demultiplex thread up to 10 seconds to each target available for

	 * reconnect -- should be greater than cifs socket timeout which is 7

	 * seconds.

	 */

	while (server->tcpStatus == CifsNeedReconnect) {

		/*
@@ -225,6 +303,9 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) 
		if (server->tcpStatus != CifsNeedReconnect)

			break;



		if (--retries)

			continue;



		/*

		 * on "soft" mounts we wait once. Hard mounts keep

		 * retrying until process is killed or server comes
@@ -234,6 +315,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) 
			cifs_dbg(FYI, "gave up waiting on reconnect in smb_init\n");

			return -EHOSTDOWN;

		}

		retries = server->nr_targets;

	}



	if (!tcon->ses->need_reconnect && !tcon->need_reconnect)
@@ -271,7 +353,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon) 
	if (tcon->use_persistent)

		tcon->need_reopen_files = true;



	rc = SMB2_tcon(0, tcon->ses, tcon->treeName, tcon, nls_codepage);

	rc = __smb2_reconnect(nls_codepage, tcon);

	mutex_unlock(&tcon->ses->session_mutex);



	cifs_dbg(FYI, "reconnect tcon rc = %d\n", rc);