Merge: Update overlayfs to v6.7

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6602

JIRA: https://issues.redhat.com/browse/RHEL-83562

Update overlayfs to the v6.7 kernel level plus bug fixes.

Three patches are reverted up front and re-applied at the proper place in the patch series.  This reduces conflicts caused by out of order application.

Omitted-fix: 853b8d7 ("remap_range: merge do_clone_file_range() into vfs_clone_file_range()")
Omitted-fix: a474d84 ("mm/shmem: refactor to reuse vfs_parse_monolithic_sep for option parsing")
Omitted-fix: 97ac489 ("fanotify: limit reporting of event with non-decodeable file handles")
Omitted-fix: 974e3fe ("fs: relax assertions on failure to encode file handles")

Signed-off-by: Miklos Szeredi <[email protected]>

Approved-by: Ian Kent <[email protected]>
Approved-by: Carlos Maiolino <[email protected]>
Approved-by: David Howells <[email protected]>
Approved-by: CKI KWF Bot <[email protected]>

Merged-by: Augusto Caringi <[email protected]>

Author: caringi

Documentation/filesystems/overlayfs.rst

@@ -240,12 +240,11 @@ Mount options:
     Redirects are enabled.
 - "redirect_dir=follow":
     Redirects are not created, but followed.
-- "redirect_dir=off":
-    Redirects are not created and only followed if "redirect_always_follow"
-    feature is enabled in the kernel/module config.
 - "redirect_dir=nofollow":
-    Redirects are not created and not followed (equivalent to "redirect_dir=off"
-    if "redirect_always_follow" feature is not enabled).
+    Redirects are not created and not followed.
+- "redirect_dir=off":
+    If "redirect_always_follow" is enabled in the kernel/module config,
+    this "off" traslates to "follow", otherwise it translates to "nofollow".
 
 When the NFS export feature is enabled, every copied up directory is
 indexed by the file handle of the lower inode and a file handle of the
@@ -349,6 +348,19 @@ The specified lower directories will be stacked beginning from the
 rightmost one and going left.  In the above example lower1 will be the
 top, lower2 the middle and lower3 the bottom layer.
 
+Note: directory names containing colons can be provided as lower layer by
+escaping the colons with a single backslash.  For example:
+
+  mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged
+
+Since kernel version v6.8, directory names containing colons can also
+be configured as lower layer using the "lowerdir+" mount options and the
+fsconfig syscall from new mount api.  For example:
+
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/a:lower::dir", 0);
+
+In the latter case, colons in lower layer directory names will be escaped
+as an octal characters (\072) when displayed in /proc/self/mountinfo.
 
 Metadata only copy up
 ---------------------
@@ -414,6 +426,16 @@ Only the data of the files in the "data-only" lower layers may be visible
 when a "metacopy" file in one of the lower layers above it, has a "redirect"
 to the absolute path of the "lower data" file in the "data-only" lower layer.
 
+Since kernel version v6.8, "data-only" lower layers can also be added using
+the "datadir+" mount options and the fsconfig syscall from new mount api.
+For example:
+
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l1", 0);
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l2", 0);
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir+", "/l3", 0);
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do1", 0);
+  fsconfig(fs_fd, FSCONFIG_SET_STRING, "datadir+", "/do2", 0);
+
 
 fs-verity support
 ----------------------
@@ -542,6 +564,9 @@ b) If a file residing on a lower layer is opened for read-only and then
 memory mapped with MAP_SHARED, then subsequent changes to the file are not
 reflected in the memory mapping.
 
+c) If a file residing on a lower layer is being executed, then opening that
+file for write or truncating the file will not be denied with ETXTBSY.
+
 The following options allow overlayfs to act more like a standards
 compliant filesystem:
 
@@ -688,6 +713,31 @@ can be useful in case the underlying disk is copied and the UUID of this copy
 is changed. This is only applicable if all lower/upper/work directories are on
 the same filesystem, otherwise it will fallback to normal behaviour.
 
+
+UUID and fsid
+-------------
+
+The UUID of overlayfs instance itself and the fsid reported by statfs(2) are
+controlled by the "uuid" mount option, which supports these values:
+
+- "null":
+    UUID of overlayfs is null. fsid is taken from upper most filesystem.
+- "off":
+    UUID of overlayfs is null. fsid is taken from upper most filesystem.
+    UUID of underlying layers is ignored.
+- "on":
+    UUID of overlayfs is generated and used to report a unique fsid.
+    UUID is stored in xattr "trusted.overlay.uuid", making overlayfs fsid
+    unique and persistent.  This option requires an overlayfs with upper
+    filesystem that supports xattrs.
+- "auto": (default)
+    UUID is taken from xattr "trusted.overlay.uuid" if it exists.
+    Upgrade to "uuid=on" on first time mount of new overlay filesystem that
+    meets the prerequites.
+    Downgrade to "uuid=null" for existing overlay filesystems that were never
+    mounted with "uuid=on".
+
+
 Volatile mount
 --------------
 

fs/fs_context.c

@@ -188,17 +188,19 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key,
 EXPORT_SYMBOL(vfs_parse_fs_string);
 
 /**
- * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
- * @ctx: The superblock configuration to fill in.
+ * vfs_parse_monolithic_sep - Parse key[=val][,key[=val]]* mount data
+ * @fc: The superblock configuration to fill in.
  * @data: The data to parse
+ * @sep: callback for separating next option
  *
- * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
- * called from the ->monolithic_mount_data() fs_context operation.
+ * Parse a blob of data that's in key[=val][,key[=val]]* form with a custom
+ * option separator callback.
  *
  * Returns 0 on success or the error returned by the ->parse_option() fs_context
  * operation on failure.
  */
-int generic_parse_monolithic(struct fs_context *fc, void *data)
+int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
+			     char *(*sep)(char **))
 {
 	char *options = data, *key;
 	int ret = 0;
@@ -210,7 +212,7 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
 	if (ret)
 		return ret;
 
-	while ((key = strsep(&options, ",")) != NULL) {
+	while ((key = sep(&options)) != NULL) {
 		if (*key) {
 			size_t v_len = 0;
 			char *value = strchr(key, '=');
@@ -229,6 +231,28 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
 
 	return ret;
 }
+EXPORT_SYMBOL(vfs_parse_monolithic_sep);
+
+static char *vfs_parse_comma_sep(char **s)
+{
+	return strsep(s, ",");
+}
+
+/**
+ * generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
+ * @fc: The superblock configuration to fill in.
+ * @data: The data to parse
+ *
+ * Parse a blob of data that's in key[=val][,key[=val]]* form.  This can be
+ * called from the ->monolithic_mount_data() fs_context operation.
+ *
+ * Returns 0 on success or the error returned by the ->parse_option() fs_context
+ * operation on failure.
+ */
+int generic_parse_monolithic(struct fs_context *fc, void *data)
+{
+	return vfs_parse_monolithic_sep(fc, data, vfs_parse_comma_sep);
+}
 EXPORT_SYMBOL(generic_parse_monolithic);
 
 /**

fs/namespace.c

@@ -361,6 +361,7 @@ int __mnt_want_write(struct vfsmount *m)
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(__mnt_want_write);
 
 /**
  * mnt_want_write - get write access to a mount
@@ -441,6 +442,7 @@ void __mnt_drop_write(struct vfsmount *mnt)
 	mnt_dec_writers(real_mount(mnt));
 	preempt_enable();
 }
+EXPORT_SYMBOL_GPL(__mnt_drop_write);
 
 /**
  * mnt_drop_write - give up write access to a mount

fs/overlayfs/Kconfig

@@ -96,7 +96,7 @@ config OVERLAY_FS_XINO_AUTO
 	depends on 64BIT
 	help
 	  If this config option is enabled then overlay filesystems will use
-	  unused high bits in undelying filesystem inode numbers to map all
+	  unused high bits in underlying filesystem inode numbers to map all
 	  inodes to a unified address space.  The mapped 64bit inode numbers
 	  might not be compatible with applications that expect 32bit inodes.
 

fs/overlayfs/Makefile

@@ -6,4 +6,4 @@
 obj-$(CONFIG_OVERLAY_FS) += overlay.o
 
 overlay-objs := super.o namei.o util.o inode.o file.o dir.o readdir.o \
-		copy_up.o export.o xattrs.o
+		copy_up.o export.o params.o xattrs.o