[PATCH v2] cifs: Show reason why autodisabling serverino support

["Pali Rohár" <pali@kernel.org>]

Extend cifs_autodisable_serverino() function to print also text message why
the function was called.

The text message is printed just once for mount then autodisabling
serverino support. Once the serverino support is disabled for mount it will
not be re-enabled. So those text messages do not cause flooding logs.

This change allows to debug issues why cifs.ko decide to turn off server
inode number support and hence disable support for detection of hardlinks.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
Paulo and Tom, could you check if this change is better now for you?
It should address problems with logs flooding and also information about
harlinks (it is already printed as can be seen also in this diff).
I would like to get your ACK, so I'm trying to improve it.
---
 fs/smb/client/cifsproto.h | 2 +-
 fs/smb/client/connect.c   | 2 +-
 fs/smb/client/dfs_cache.c | 2 +-
 fs/smb/client/inode.c     | 6 +++---
 fs/smb/client/misc.c      | 6 +++++-
 fs/smb/client/readdir.c   | 4 ++--
 6 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/fs/smb/client/cifsproto.h b/fs/smb/client/cifsproto.h
index d550662b4e72..07a67c8c37ce 100644
--- a/fs/smb/client/cifsproto.h
+++ b/fs/smb/client/cifsproto.h
@@ -586,9 +586,9 @@ extern int cifs_do_set_acl(const unsigned int xid, struct cifs_tcon *tcon,
 			   const struct nls_table *nls_codepage, int remap);
 extern int CIFSGetExtAttr(const unsigned int xid, struct cifs_tcon *tcon,
 			const int netfid, __u64 *pExtAttrBits, __u64 *pMask);
 #endif /* CIFS_ALLOW_INSECURE_LEGACY */
-extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb);
+extern void cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb, const char *reason, int rc);
 extern bool couldbe_mf_symlink(const struct cifs_fattr *fattr);
 extern int check_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 			      struct cifs_sb_info *cifs_sb,
 			      struct cifs_fattr *fattr,
diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c
index 6bf04d9a5491..819721dfd5bb 100644
--- a/fs/smb/client/connect.c
+++ b/fs/smb/client/connect.c
@@ -3907,9 +3907,9 @@ int cifs_mount(struct cifs_sb_info *cifs_sb, struct smb3_fs_context *ctx)
 	/*
 	 * After reconnecting to a different server, unique ids won't match anymore, so we disable
 	 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
 	 */
-	cifs_autodisable_serverino(cifs_sb);
+	cifs_autodisable_serverino(cifs_sb, "Reconnecting to different server, inode numbers won't match anymore", 0);
 	/*
 	 * Force the use of prefix path to support failover on DFS paths that resolve to targets
 	 * that have different prefix paths.
 	 */
diff --git a/fs/smb/client/dfs_cache.c b/fs/smb/client/dfs_cache.c
index 4dada26d56b5..c3fe85c31e2b 100644
--- a/fs/smb/client/dfs_cache.c
+++ b/fs/smb/client/dfs_cache.c
@@ -1288,9 +1288,9 @@ int dfs_cache_remount_fs(struct cifs_sb_info *cifs_sb)
 	/*
 	 * After reconnecting to a different server, unique ids won't match anymore, so we disable
 	 * serverino. This prevents dentry revalidation to think the dentry are stale (ESTALE).
 	 */
-	cifs_autodisable_serverino(cifs_sb);
+	cifs_autodisable_serverino(cifs_sb, "Reconnecting to different server, inode numbers won't match anymore", 0);
 	/*
 	 * Force the use of prefix path to support failover on DFS paths that resolve to targets
 	 * that have different prefix paths.
 	 */
diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
index cd06598eacbd..b1c6e3986278 100644
--- a/fs/smb/client/inode.c
+++ b/fs/smb/client/inode.c
@@ -1076,9 +1076,9 @@ static void cifs_set_fattr_ino(int xid, struct cifs_tcon *tcon, struct super_blo
 		if (*inode)
 			fattr->cf_uniqueid = CIFS_I(*inode)->uniqueid;
 		else {
 			fattr->cf_uniqueid = iunique(sb, ROOT_I);
-			cifs_autodisable_serverino(cifs_sb);
+			cifs_autodisable_serverino(cifs_sb, "Cannot retrieve inode number via get_srv_inum", rc);
 		}
 		return;
 	}
 
@@ -1529,9 +1529,9 @@ cifs_iget(struct super_block *sb, struct cifs_fattr *fattr)
 		if (fattr->cf_flags & CIFS_FATTR_INO_COLLISION) {
 			fattr->cf_flags &= ~CIFS_FATTR_INO_COLLISION;
 
 			if (inode_has_hashed_dentries(inode)) {
-				cifs_autodisable_serverino(CIFS_SB(sb));
+				cifs_autodisable_serverino(CIFS_SB(sb), "Inode number collision detected", 0);
 				iput(inode);
 				fattr->cf_uniqueid = iunique(sb, ROOT_I);
 				goto retry_iget5_locked;
 			}
@@ -1596,9 +1596,9 @@ struct inode *cifs_root_iget(struct super_block *sb)
 iget_root:
 	if (!rc) {
 		if (fattr.cf_flags & CIFS_FATTR_JUNCTION) {
 			fattr.cf_flags &= ~CIFS_FATTR_JUNCTION;
-			cifs_autodisable_serverino(cifs_sb);
+			cifs_autodisable_serverino(cifs_sb, "Cannot retrieve attributes for junction point", rc);
 		}
 		inode = cifs_iget(sb, &fattr);
 	}
 
diff --git a/fs/smb/client/misc.c b/fs/smb/client/misc.c
index e77017f47084..409277883e8a 100644
--- a/fs/smb/client/misc.c
+++ b/fs/smb/client/misc.c
@@ -551,9 +551,9 @@ dump_smb(void *buf, int smb_buf_length)
 		       smb_buf_length, true);
 }
 
 void
-cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
+cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb, const char *reason, int rc)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM) {
 		struct cifs_tcon *tcon = NULL;
 
@@ -561,8 +561,12 @@ cifs_autodisable_serverino(struct cifs_sb_info *cifs_sb)
 			tcon = cifs_sb_master_tcon(cifs_sb);
 
 		cifs_sb->mnt_cifs_flags &= ~CIFS_MOUNT_SERVER_INUM;
 		cifs_sb->mnt_cifs_serverino_autodisabled = true;
+		if (rc)
+			cifs_dbg(VFS, "%s: %d\n", reason, rc);
+		else
+			cifs_dbg(VFS, "%s\n", reason);
 		cifs_dbg(VFS, "Autodisabling the use of server inode numbers on %s\n",
 			 tcon ? tcon->tree_name : "new server");
 		cifs_dbg(VFS, "The server doesn't seem to support them properly or the files might be on different servers (DFS)\n");
 		cifs_dbg(VFS, "Hardlinks will not be recognized on this mount. Consider mounting with the \"noserverino\" option to silence this message.\n");
diff --git a/fs/smb/client/readdir.c b/fs/smb/client/readdir.c
index 787d6bcb5d1d..06e90921f751 100644
--- a/fs/smb/client/readdir.c
+++ b/fs/smb/client/readdir.c
@@ -412,9 +412,9 @@ _initiate_cifs_search(const unsigned int xid, struct file *file,
 	if (rc == 0) {
 		cifsFile->invalidHandle = false;
 	} else if ((rc == -EOPNOTSUPP) &&
 		   (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
-		cifs_autodisable_serverino(cifs_sb);
+		cifs_autodisable_serverino(cifs_sb, "Cannot retrieve inode number via query_dir_first", rc);
 		goto ffirst_retry;
 	}
 error_exit:
 	cifs_put_tlink(tlink);
@@ -1006,9 +1006,9 @@ static int cifs_filldir(char *find_entry, struct file *file,
 	if (de.ino && (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SERVER_INUM)) {
 		fattr.cf_uniqueid = de.ino;
 	} else {
 		fattr.cf_uniqueid = iunique(sb, ROOT_I);
-		cifs_autodisable_serverino(cifs_sb);
+		cifs_autodisable_serverino(cifs_sb, "Cannot retrieve inode number", 0);
 	}
 
 	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MF_SYMLINKS) &&
 	    couldbe_mf_symlink(&fattr))
-- 
2.20.1