afs: Add comments on abort handling (fe245c8f) · Commits · git / linux-net

fs/afs/rotate.c

+90 −11

Original line number	Diff line number	Diff line
		@@ -13,6 +13,7 @@
		#include <linux/sched/signal.h>
		#include "internal.h"
		#include "afs_fs.h"
		#include "protocol_uae.h"

		/*
		* Begin iteration through a server list, starting with the vnode's last used
		@@ -143,6 +144,11 @@ bool afs_select_fileserver(struct afs_operation *op)
		case -ECONNABORTED:
		/* The far side rejected the operation on some grounds. This
		* might involve the server being busy or the volume having been moved.
		*
		* Note that various V* errors should not be sent to a cache manager
		* by a fileserver as they should be translated to more modern UAE*
		* errors instead. IBM AFS and OpenAFS fileservers, however, do leak
		* these abort codes.
		*/
		switch (op->ac.abort_code) {
		case VNOVOL:
		@@ -150,6 +156,11 @@ bool afs_select_fileserver(struct afs_operation *op)
		* - May indicate that the VL is wrong - retry once and compare
		* the results.
		* - May indicate that the fileserver couldn't attach to the vol.
		* - The volume might have been temporarily removed so that it can
		* be replaced by a volume restore. "vos" might have ended one
		* transaction and has yet to create the next.
		* - The volume might not be blessed or might not be in-service
		* (administrative action).
		*/
		if (op->flags & AFS_OPERATION_VNOVOL) {
		op->error = -EREMOTEIO;
		@@ -183,16 +194,56 @@ bool afs_select_fileserver(struct afs_operation *op)
		_leave(" = t [vnovol]");
		return true;

		case VSALVAGE: /* TODO: Should this return an error or iterate? */
		case VVOLEXISTS:
		case VNOSERVICE:
		case VONLINE:
		case VDISKFULL:
		case VOVERQUOTA:
		op->error = afs_abort_to_error(op->ac.abort_code);
		/* These should not be returned from the fileserver. */
		pr_warn("Fileserver returned unexpected abort %d\n",
		op->ac.abort_code);
		op->error = -EREMOTEIO;
		goto next_server;

		case VNOSERVICE:
		/* Prior to AFS 3.2 VNOSERVICE was returned from the fileserver
		* if the volume was neither in-service nor administratively
		* blessed. All usage was replaced by VNOVOL because AFS 3.1 and
		* earlier cache managers did not handle VNOSERVICE and assumed
		* it was the client OSes errno 105.
		*
		* Starting with OpenAFS 1.4.8 VNOSERVICE was repurposed as the
		* fileserver idle dead time error which was sent in place of
		* RX_CALL_TIMEOUT (-3). The error was intended to be sent if the
		* fileserver took too long to send a reply to the client.
		* RX_CALL_TIMEOUT would have caused the cache manager to mark the
		* server down whereas VNOSERVICE since AFS 3.2 would cause cache
		* manager to temporarily (up to 15 minutes) mark the volume
		* instance as unusable.
		*
		* The idle dead logic resulted in cache inconsistency since a
		* state changing call that the cache manager assumed was dead
		* could still be processed to completion by the fileserver. This
		* logic was removed in OpenAFS 1.8.0 and VNOSERVICE is no longer
		* returned. However, many 1.4.8 through 1.6.24 fileservers are
		* still in existence.
		*
		* AuriStorFS fileservers have never returned VNOSERVICE.
		*
		* VNOSERVICE should be treated as an alias for RX_CALL_TIMEOUT.
		*/
		case RX_CALL_TIMEOUT:
		op->error = -ETIMEDOUT;
		goto next_server;

		case VSALVAGING: /* This error should not be leaked to cache managers
		* but is from OpenAFS demand attach fileservers.
		* It should be treated as an alias for VOFFLINE.
		*/
		case VSALVAGE: /* VSALVAGE should be treated as a synonym of VOFFLINE */
		case VOFFLINE:
		/* The volume is in use by the volserver or another volume utility
		* for an operation that might alter the contents. The volume is
		* expected to come back but it might take a long time (could be
		* days).
		*/
		if (!test_and_set_bit(AFS_VOLUME_OFFLINE, &op->volume->flags)) {
		afs_busy(op->volume, op->ac.abort_code);
		clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
		@@ -207,11 +258,20 @@ bool afs_select_fileserver(struct afs_operation *op)
		}
		goto busy;

		case VSALVAGING:
		case VRESTARTING:
		case VRESTARTING: /* The fileserver is either shutting down or starting up. */
		case VBUSY:
		/* Retry after going round all the servers unless we
		* have a file lock we need to maintain.
		/* The volume is in use by the volserver or another volume
		* utility for an operation that is not expected to alter the
		* contents of the volume. VBUSY does not need to be returned
		* for a ROVOL or BACKVOL bound to an ITBusy volserver
		* transaction. The fileserver is permitted to continue serving
		* content from ROVOLs and BACKVOLs during an ITBusy transaction
		* because the content will not change. However, many fileserver
		* releases do return VBUSY for ROVOL and BACKVOL instances under
		* many circumstances.
		*
		* Retry after going round all the servers unless we have a file
		* lock we need to maintain.
		*/
		if (op->flags & AFS_OPERATION_NO_VSLEEP) {
		op->error = -EBUSY;
		@@ -270,10 +330,29 @@ bool afs_select_fileserver(struct afs_operation *op)

		goto restart_from_beginning;

		case VDISKFULL:
		case UAENOSPC:
		/* The partition is full. Only applies to RWVOLs.
		* Translate locally and return ENOSPC.
		* No replicas to failover to.
		*/
		op->error = -ENOSPC;
		goto failed_but_online;

		case VOVERQUOTA:
		case UAEDQUOT:
		/* Volume is full. Only applies to RWVOLs.
		* Translate locally and return EDQUOT.
		* No replicas to failover to.
		*/
		op->error = -EDQUOT;
		goto failed_but_online;

		default:
		op->error = afs_abort_to_error(op->ac.abort_code);
		failed_but_online:
		clear_bit(AFS_VOLUME_OFFLINE, &op->volume->flags);
		clear_bit(AFS_VOLUME_BUSY, &op->volume->flags);
		op->error = afs_abort_to_error(op->ac.abort_code);
		goto failed;
		}