linux-kernel - [PATCH AUTOSEL 5.18 38/49] cifs: return ENOENT for DFS lookup_cache

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Date:   Wed,  1 Jun 2022 09:52:02 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Enzo Matsumiya <ematsumiya@...e.de>, Paulo Alcantara <pc@....nz>,
        Steve French <stfrench@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>, sfrench@...ba.org,
        linux-cifs@...r.kernel.org, samba-technical@...ts.samba.org
Subject: [PATCH AUTOSEL 5.18 38/49] cifs: return ENOENT for DFS lookup_cache_entry()

From: Enzo Matsumiya <ematsumiya@...e.de>

[ Upstream commit 337b8b0e4343567221ef8d88aac5e418208d4ac1 ]

EEXIST didn't make sense to use when dfs_cache_find() couldn't find a
cache entry nor retrieve a referral target.

It also doesn't make sense cifs_dfs_query_info_nonascii_quirk() to
emulate ENOENT anymore.

Signed-off-by: Enzo Matsumiya <ematsumiya@...e.de>
Reviewed-by: Paulo Alcantara (SUSE) <pc@....nz>
Signed-off-by: Steve French <stfrench@...rosoft.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/cifs/connect.c   | 6 ++++--
 fs/cifs/dfs_cache.c | 6 +++---
 fs/cifs/misc.c      | 6 +-----
 3 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 42e14f408856..8e3fa59813e7 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3420,8 +3420,9 @@ cifs_are_all_path_components_accessible(struct TCP_Server_Info *server,
 }
 
 /*
- * Check if path is remote (e.g. a DFS share). Return -EREMOTE if it is,
- * otherwise 0.
+ * Check if path is remote (i.e. a DFS share).
+ *
+ * Return -EREMOTE if it is, otherwise 0 or -errno.
  */
 static int is_path_remote(struct mount_ctx *mnt_ctx)
 {
@@ -3703,6 +3704,7 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 	if (!isdfs)
 		goto out;
 
+	/* proceed as DFS mount */
 	uuid_gen(&mnt_ctx.mount_id);
 	rc = connect_dfs_root(&mnt_ctx, &tl);
 	dfs_cache_free_tgts(&tl);
diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 956f8e5cf3e7..c5dd6f7305bd 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -654,7 +654,7 @@ static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int h
 			return ce;
 		}
 	}
-	return ERR_PTR(-EEXIST);
+	return ERR_PTR(-ENOENT);
 }
 
 /*
@@ -662,7 +662,7 @@ static struct cache_entry *__lookup_cache_entry(const char *path, unsigned int h
  *
  * Use whole path components in the match.  Must be called with htable_rw_lock held.
  *
- * Return ERR_PTR(-EEXIST) if the entry is not found.
+ * Return ERR_PTR(-ENOENT) if the entry is not found.
  */
 static struct cache_entry *lookup_cache_entry(const char *path)
 {
@@ -710,7 +710,7 @@ static struct cache_entry *lookup_cache_entry(const char *path)
 		while (e > s && *e != sep)
 			e--;
 	}
-	return ERR_PTR(-EEXIST);
+	return ERR_PTR(-ENOENT);
 }
 
 /**
diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
index afaf59c22193..a5b5b15e658a 100644
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -1309,7 +1309,7 @@ int cifs_update_super_prepath(struct cifs_sb_info *cifs_sb, char *prefix)
  * for "\<server>\<dfsname>\<linkpath>" DFS reference,
  * where <dfsname> contains non-ASCII unicode symbols.
  *
- * Check such DFS reference and emulate -ENOENT if it is actual.
+ * Check such DFS reference.
  */
 int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid,
 				       struct cifs_tcon *tcon,
@@ -1341,10 +1341,6 @@ int cifs_dfs_query_info_nonascii_quirk(const unsigned int xid,
 		cifs_dbg(FYI, "DFS ref '%s' is found, emulate -EREMOTE\n",
 			 dfspath);
 		rc = -EREMOTE;
-	} else if (rc == -EEXIST) {
-		cifs_dbg(FYI, "DFS ref '%s' is not found, emulate -ENOENT\n",
-			 dfspath);
-		rc = -ENOENT;
 	} else {
 		cifs_dbg(FYI, "%s: dfs_cache_find returned %d\n", __func__, rc);
 	}
-- 
2.35.1