Commit 744bcd71 authored by David Howells's avatar David Howells
Browse files

afs: Allow dumping of server cursor on operation failure 



Provide an option to allow the file or volume location server cursor to be
dumped if the rotation routine falls off the end without managing to
contact a server.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
parent 30062bd1

fs/afs/Kconfig

+12 −0
Original line number Diff line number Diff line
@@ -27,3 +27,15 @@ config AFS_FSCACHE 
	help

	  Say Y here if you want AFS data to be cached locally on disk through

	  the generic filesystem cache manager



config AFS_DEBUG_CURSOR

	bool "AFS server cursor debugging"

	depends on AFS_FS

	help

	  Say Y here to cause the contents of a server cursor to be dumped to

	  the dmesg log if the server rotation algorithm fails to successfully

	  contact a server.



	  See <file:Documentation/filesystems/afs.txt> for more information.



	  If unsure, say N.

fs/afs/addr_list.c

+2 −0
Original line number Diff line number Diff line
@@ -358,6 +358,8 @@ bool afs_iterate_addresses(struct afs_addr_cursor *ac) 
	if (!ac->alist)

		return false;



	ac->nr_iterations++;



	if (ac->begun) {

		ac->index++;

		if (ac->index == ac->alist->nr_addrs)

fs/afs/internal.h

+3 −0
Original line number Diff line number Diff line
@@ -660,6 +660,7 @@ struct afs_addr_cursor { 
	short			error;

	bool			begun;		/* T if we've begun iteration */

	bool			responded;	/* T if the current address responded */

	unsigned short		nr_iterations;	/* Number of address iterations */

};



/*
@@ -677,6 +678,7 @@ struct afs_vl_cursor { 
#define AFS_VL_CURSOR_STOP	0x0001		/* Set to cease iteration */

#define AFS_VL_CURSOR_RETRY	0x0002		/* Set to do a retry */

#define AFS_VL_CURSOR_RETRIED	0x0004		/* Set if started a retry */

	unsigned short		nr_iterations;	/* Number of server iterations */

};



/*
@@ -700,6 +702,7 @@ struct afs_fs_cursor { 
#define AFS_FS_CURSOR_VNOVOL	0x0008		/* Set if seen VNOVOL */

#define AFS_FS_CURSOR_CUR_ONLY	0x0010		/* Set if current server only (file lock held) */

#define AFS_FS_CURSOR_NO_VSLEEP	0x0020		/* Set to prevent sleep on VBUSY, VOFFLINE, ... */

	unsigned short		nr_iterations;	/* Number of server iterations */

};



/*

fs/afs/rotate.c

+57 −0
Original line number Diff line number Diff line
@@ -156,6 +156,8 @@ bool afs_select_fileserver(struct afs_fs_cursor *fc) 
		return false;

	}



	fc->nr_iterations++;



	/* Evaluate the result of the previous operation, if there was one. */

	switch (error) {

	case SHRT_MAX:
@@ -519,6 +521,56 @@ bool afs_select_current_fileserver(struct afs_fs_cursor *fc) 
	return false;

}



/*

 * Dump cursor state in the case of the error being EDESTADDRREQ.

 */

static void afs_dump_edestaddrreq(const struct afs_fs_cursor *fc)

{

	static int count;

	int i;



	if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)

		return;

	count++;



	rcu_read_lock();



	pr_notice("EDESTADDR occurred\n");

	pr_notice("FC: cbb=%x cbb2=%x fl=%hx err=%hd\n",

		  fc->cb_break, fc->cb_break_2, fc->flags, fc->error);

	pr_notice("FC: st=%u ix=%u ni=%u\n",

		  fc->start, fc->index, fc->nr_iterations);



	if (fc->server_list) {

		const struct afs_server_list *sl = fc->server_list;

		pr_notice("FC: SL nr=%u ix=%u vnov=%hx\n",

			  sl->nr_servers, sl->index, sl->vnovol_mask);

		for (i = 0; i < sl->nr_servers; i++) {

			const struct afs_server *s = sl->servers[i].server;

			pr_notice("FC: server fl=%lx av=%u %pU\n",

				  s->flags, s->addr_version, &s->uuid);

			if (s->addresses) {

				const struct afs_addr_list *a =

					rcu_dereference(s->addresses);

				pr_notice("FC:  - av=%u nr=%u/%u/%u ax=%u\n",

					  a->version,

					  a->nr_ipv4, a->nr_addrs, a->max_addrs,

					  a->index);

				pr_notice("FC:  - pr=%lx yf=%lx\n",

					  a->probed, a->yfs);

				if (a == fc->ac.alist)

					pr_notice("FC:  - current\n");

			}

		}

	}



	pr_notice("AC: as=%u ax=%u ac=%d er=%d b=%u r=%u ni=%u\n",

		  fc->ac.start, fc->ac.index, fc->ac.abort_code, fc->ac.error,

		  fc->ac.begun, fc->ac.responded, fc->ac.nr_iterations);



	rcu_read_unlock();

}



/*

 * Tidy up a filesystem cursor and unlock the vnode.

 */
@@ -526,6 +578,11 @@ int afs_end_vnode_operation(struct afs_fs_cursor *fc) 
{

	struct afs_net *net = afs_v2net(fc->vnode);



	if (fc->error == -EDESTADDRREQ ||

	    fc->error == -ENETUNREACH ||

	    fc->error == -EHOSTUNREACH)

		afs_dump_edestaddrreq(fc);



	mutex_unlock(&fc->vnode->io_lock);



	afs_end_cursor(&fc->ac);

fs/afs/vl_rotate.c

+53 −0
Original line number Diff line number Diff line
@@ -83,6 +83,8 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc) 
		return false;

	}



	vc->nr_iterations++;



	/* Evaluate the result of the previous operation, if there was one. */

	switch (error) {

	case SHRT_MAX:
@@ -234,6 +236,52 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc) 
	return false;

}



/*

 * Dump cursor state in the case of the error being EDESTADDRREQ.

 */

static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)

{

	static int count;

	int i;



	if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)

		return;

	count++;



	rcu_read_lock();

	pr_notice("EDESTADDR occurred\n");

	pr_notice("VC: st=%u ix=%u ni=%hu fl=%hx err=%hd\n",

		  vc->start, vc->index, vc->nr_iterations, vc->flags, vc->error);



	if (vc->server_list) {

		const struct afs_vlserver_list *sl = vc->server_list;

		pr_notice("VC: SL nr=%u ix=%u\n",

			  sl->nr_servers, sl->index);

		for (i = 0; i < sl->nr_servers; i++) {

			const struct afs_vlserver *s = sl->servers[i].server;

			pr_notice("VC: server fl=%lx %s+%hu\n",

				  s->flags, s->name, s->port);

			if (s->addresses) {

				const struct afs_addr_list *a =

					rcu_dereference(s->addresses);

				pr_notice("VC:  - av=%u nr=%u/%u/%u ax=%u\n",

					  a->version,

					  a->nr_ipv4, a->nr_addrs, a->max_addrs,

					  a->index);

				pr_notice("VC:  - pr=%lx yf=%lx\n",

					  a->probed, a->yfs);

				if (a == vc->ac.alist)

					pr_notice("VC:  - current\n");

			}

		}

	}



	pr_notice("AC: as=%u ax=%u ac=%d er=%d b=%u r=%u ni=%hu\n",

		  vc->ac.start, vc->ac.index, vc->ac.abort_code, vc->ac.error,

		  vc->ac.begun, vc->ac.responded, vc->ac.nr_iterations);

	rcu_read_unlock();

}



/*

 * Tidy up a volume location server cursor and unlock the vnode.

 */
@@ -241,6 +289,11 @@ int afs_end_vlserver_operation(struct afs_vl_cursor *vc) 
{

	struct afs_net *net = vc->cell->net;



	if (vc->error == -EDESTADDRREQ ||

	    vc->error == -ENETUNREACH ||

	    vc->error == -EHOSTUNREACH)

		afs_vl_dump_edestaddrreq(vc);



	afs_end_cursor(&vc->ac);

	afs_put_vlserverlist(net, vc->server_list);