Commit 5433c629 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

smb: client: optimize referral walk on failed link targets 



If a link referral request sent to root server was successful but
client failed to connect to all link targets, there is no need to
retry same link referral on a different root server.  Set an end
marker for the DFS root referral so the client will not attempt to
re-send link referrals to different root servers on failures.

Signed-off-by: default avatarPaulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 4b1b4c8b

fs/smb/client/dfs.c

+26 −43
Original line number Diff line number Diff line
@@ -98,15 +98,16 @@ static inline int parse_dfs_target(struct smb3_fs_context *ctx, 
	return rc;

}



static int setup_dfs_ref(struct cifs_mount_ctx *mnt_ctx,

			 struct dfs_info3_param *tgt,

			 struct dfs_ref_walk *rw)

static int setup_dfs_ref(struct dfs_info3_param *tgt, struct dfs_ref_walk *rw)

{

	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;

	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;

	struct cifs_sb_info *cifs_sb = rw->mnt_ctx->cifs_sb;

	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;

	char *ref_path, *full_path;

	int rc;



	set_root_smb_session(rw->mnt_ctx);

	ref_walk_ses(rw) = ctx->dfs_root_ses;



	full_path = smb3_fs_context_fullpath(ctx, CIFS_DIR_SEP(cifs_sb));

	if (IS_ERR(full_path))

		return PTR_ERR(full_path);
@@ -123,35 +124,22 @@ static int setup_dfs_ref(struct cifs_mount_ctx *mnt_ctx, 
	}

	ref_walk_path(rw) = ref_path;

	ref_walk_fpath(rw) = full_path;

	ref_walk_ses(rw) = ctx->dfs_root_ses;

	return 0;



	return dfs_get_referral(rw->mnt_ctx,

				ref_walk_path(rw) + 1,

				ref_walk_tl(rw));

}



static int __dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx,

			       struct dfs_ref_walk *rw)

static int __dfs_referral_walk(struct dfs_ref_walk *rw)

{

	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;

	struct smb3_fs_context *ctx = rw->mnt_ctx->fs_ctx;

	struct cifs_mount_ctx *mnt_ctx = rw->mnt_ctx;

	struct dfs_info3_param tgt = {};

	int rc = -ENOENT;



again:

	do {

		ctx->dfs_root_ses = ref_walk_ses(rw);

		if (ref_walk_empty(rw)) {

			rc = dfs_get_referral(mnt_ctx, ref_walk_path(rw) + 1,

					      NULL, ref_walk_tl(rw));

			if (rc) {

				rc = cifs_mount_get_tcon(mnt_ctx);

				if (!rc)

					rc = cifs_is_path_remote(mnt_ctx);

				continue;

			}

			if (!ref_walk_num_tgts(rw)) {

				rc = -ENOENT;

				continue;

			}

		}



		while (ref_walk_next_tgt(rw)) {

			rc = parse_dfs_target(ctx, rw, &tgt);

			if (rc)
@@ -162,32 +150,29 @@ static int __dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx, 
			if (rc)

				continue;



			ref_walk_set_tgt_hint(rw);

			if (tgt.flags & DFSREF_STORAGE_SERVER) {

				rc = cifs_mount_get_tcon(mnt_ctx);

				if (!rc)

					rc = cifs_is_path_remote(mnt_ctx);

				if (!rc)

				if (!rc) {

					ref_walk_set_tgt_hint(rw);

					break;

				}

				if (rc != -EREMOTE)

					continue;

			}



			set_root_smb_session(mnt_ctx);

			rc = ref_walk_advance(rw);

			if (!rc) {

				rc = setup_dfs_ref(mnt_ctx, &tgt, rw);

				if (!rc) {

					rc = -EREMOTE;

				rc = setup_dfs_ref(&tgt, rw);

				if (rc)

					break;

				ref_walk_mark_end(rw);

				goto again;

			}

		}

			if (rc != -ELOOP)

				goto out;

		}

	} while (rc && ref_walk_descend(rw));



out:

	free_dfs_info_param(&tgt);

	return rc;

}
@@ -204,10 +189,10 @@ static int dfs_referral_walk(struct cifs_mount_ctx *mnt_ctx, 
		return rc;

	}



	ref_walk_init(*rw);

	rc = setup_dfs_ref(mnt_ctx, NULL, *rw);

	ref_walk_init(*rw, mnt_ctx);

	rc = setup_dfs_ref(NULL, *rw);

	if (!rc)

		rc = __dfs_referral_walk(mnt_ctx, *rw);

		rc = __dfs_referral_walk(*rw);

	return rc;

}
@@ -297,7 +282,7 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx) 
	 * to respond with PATH_NOT_COVERED to requests that include the prefix.

	 */

	if (!nodfs) {

		rc = dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL, NULL);

		rc = dfs_get_referral(mnt_ctx, ctx->UNC + 1, NULL);

		if (rc) {

			cifs_dbg(FYI, "%s: no dfs referral for %s: %d\n",

				 __func__, ctx->UNC + 1, rc);
@@ -317,10 +302,8 @@ int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx) 
		cifs_mount_put_conns(mnt_ctx);

		rc = get_session(mnt_ctx, NULL);

	}

	if (!rc) {

		set_root_smb_session(mnt_ctx);

	if (!rc)

		rc = __dfs_mount_share(mnt_ctx);

	}

	return rc;

}

fs/smb/client/dfs.h

+30 −14
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include "dfs_cache.h"

#include "cifs_unicode.h"

#include <linux/namei.h>

#include <linux/errno.h>



#define DFS_INTERLINK(v) \

	(((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
@@ -25,6 +26,7 @@ struct dfs_ref { 
};



struct dfs_ref_walk {

	struct cifs_mount_ctx	*mnt_ctx;

	struct dfs_ref		*ref;

	struct dfs_ref		refs[MAX_NESTED_LINKS];

};
@@ -35,7 +37,6 @@ struct dfs_ref_walk { 
#define ref_walk_descend(w)	(--ref_walk_cur(w) >= ref_walk_start(w))



#define ref_walk_tit(w)	(ref_walk_cur(w)->tit)

#define ref_walk_empty(w)	(!ref_walk_tit(w))

#define ref_walk_path(w)	(ref_walk_cur(w)->path)

#define ref_walk_fpath(w)	(ref_walk_cur(w)->full_path)

#define ref_walk_tl(w)		(&ref_walk_cur(w)->tl)
@@ -51,9 +52,11 @@ static inline struct dfs_ref_walk *ref_walk_alloc(void) 
	return rw;

}



static inline void ref_walk_init(struct dfs_ref_walk *rw)

static inline void ref_walk_init(struct dfs_ref_walk *rw,

				 struct cifs_mount_ctx *mnt_ctx)

{

	memset(rw, 0, sizeof(*rw));

	rw->mnt_ctx = mnt_ctx;

	ref_walk_cur(rw) = ref_walk_start(rw);

}
@@ -93,15 +96,23 @@ static inline int ref_walk_advance(struct dfs_ref_walk *rw) 
static inline struct dfs_cache_tgt_iterator *

ref_walk_next_tgt(struct dfs_ref_walk *rw)

{

	struct dfs_cache_tgt_iterator *tit;

	struct dfs_ref *ref = ref_walk_cur(rw);

	struct dfs_cache_tgt_iterator *tit;



	if (IS_ERR(ref->tit))

		return NULL;



	if (!ref->tit)

		tit = dfs_cache_get_tgt_iterator(&ref->tl);

	else

		tit = dfs_cache_get_next_tgt(&ref->tl, ref->tit);



	if (!tit) {

		ref->tit = ERR_PTR(-ENOENT);

		return NULL;

	}

	ref->tit = tit;

	return tit;

	return ref->tit;

}



static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw,
@@ -112,11 +123,6 @@ static inline int ref_walk_get_tgt(struct dfs_ref_walk *rw, 
					  ref_walk_tit(rw), tgt);

}



static inline int ref_walk_num_tgts(struct dfs_ref_walk *rw)

{

	return dfs_cache_get_nr_tgts(ref_walk_tl(rw));

}



static inline void ref_walk_set_tgt_hint(struct dfs_ref_walk *rw)

{

	dfs_cache_noreq_update_tgthint(ref_walk_path(rw) + 1,
@@ -136,6 +142,15 @@ static inline void ref_walk_set_tcon(struct dfs_ref_walk *rw, 
	}

}



static inline void ref_walk_mark_end(struct dfs_ref_walk *rw)

{

	struct dfs_ref *ref = ref_walk_cur(rw) - 1;



	WARN_ON_ONCE(ref < ref_walk_start(rw));

	dfs_cache_noreq_update_tgthint(ref->path + 1, ref->tit);

	ref->tit = ERR_PTR(-ENOENT); /* end marker */

}



int dfs_parse_target_referral(const char *full_path, const struct dfs_info3_param *ref,

			      struct smb3_fs_context *ctx);

int dfs_mount_share(struct cifs_mount_ctx *mnt_ctx);
@@ -145,15 +160,16 @@ static inline char *dfs_get_path(struct cifs_sb_info *cifs_sb, const char *path) 
	return dfs_cache_canonical_path(path, cifs_sb->local_nls, cifs_remap(cifs_sb));

}



static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx, const char *path,

				   struct dfs_info3_param *ref, struct dfs_cache_tgt_list *tl)

static inline int dfs_get_referral(struct cifs_mount_ctx *mnt_ctx,

				   const char *path,

				   struct dfs_cache_tgt_list *tl)

{

	struct smb3_fs_context *ctx = mnt_ctx->fs_ctx;

	struct cifs_sb_info *cifs_sb = mnt_ctx->cifs_sb;

	struct cifs_ses *rses = ctx->dfs_root_ses ?: mnt_ctx->ses;



	return dfs_cache_find(mnt_ctx->xid, rses, cifs_sb->local_nls,

			      cifs_remap(cifs_sb), path, ref, tl);

			      cifs_remap(cifs_sb), path, NULL, tl);

}



/*