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smb: client: optimize referral walk on failed link targets

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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: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara
2025-01-10 15:58:08 -03:00
committed by Steve French
parent 4b1b4c8be9
commit 5433c629e8
2 changed files with 56 additions and 57 deletions
Download Patch File Download Diff File Expand all files Collapse all files

69
fs/smb/client/dfs.c
View File

@@ -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;
goto again;
}
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;
}

44
fs/smb/client/dfs.h
View File

@@ -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))
@@ -25,8 +26,9 @@ struct dfs_ref {
};
struct dfs_ref_walk {
struct dfs_ref *ref;
struct dfs_ref refs[MAX_NESTED_LINKS];
struct cifs_mount_ctx *mnt_ctx;
struct dfs_ref *ref;
struct dfs_ref refs[MAX_NESTED_LINKS];
};
#define ref_walk_start(w) ((w)->refs)
@@ -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);
}
/*