1 files changed, 255 insertions, 10 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 87c9e38c0763..c7881e16f4be 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -40,6 +40,7 @@
 #include <linux/fs_parser.h>
 #include <linux/swapfile.h>
 #include <linux/iversion.h>
+#include <linux/unicode.h>
 #include "swap.h"
 
 static struct vfsmount *shm_mnt __ro_after_init;
@@ -123,6 +124,10 @@ struct shmem_options {
 	bool noswap;
 	unsigned short quota_types;
 	struct shmem_quota_limits qlimits;
+#if IS_ENABLED(CONFIG_UNICODE)
+	struct unicode_map *encoding;
+	bool strict_encoding;
+#endif
 #define SHMEM_SEEN_BLOCKS 1
 #define SHMEM_SEEN_INODES 2
 #define SHMEM_SEEN_HUGE 4
@@ -2749,13 +2754,62 @@ static int shmem_file_open(struct inode *inode, struct file *file)
 #ifdef CONFIG_TMPFS_XATTR
 static int shmem_initxattrs(struct inode *, const struct xattr *, void *);
 
+#if IS_ENABLED(CONFIG_UNICODE)
+/*
+ * shmem_inode_casefold_flags - Deal with casefold file attribute flag
+ *
+ * The casefold file attribute needs some special checks. I can just be added to
+ * an empty dir, and can't be removed from a non-empty dir.
+ */
+static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags,
+				      struct dentry *dentry, unsigned int *i_flags)
+{
+	unsigned int old = inode->i_flags;
+	struct super_block *sb = inode->i_sb;
+
+	if (fsflags & FS_CASEFOLD_FL) {
+		if (!(old & S_CASEFOLD)) {
+			if (!sb->s_encoding)
+				return -EOPNOTSUPP;
+
+			if (!S_ISDIR(inode->i_mode))
+				return -ENOTDIR;
+
+			if (dentry && !simple_empty(dentry))
+				return -ENOTEMPTY;
+		}
+
+		*i_flags = *i_flags | S_CASEFOLD;
+	} else if (old & S_CASEFOLD) {
+		if (dentry && !simple_empty(dentry))
+			return -ENOTEMPTY;
+	}
+
+	return 0;
+}
+#else
+static int shmem_inode_casefold_flags(struct inode *inode, unsigned int fsflags,
+				      struct dentry *dentry, unsigned int *i_flags)
+{
+	if (fsflags & FS_CASEFOLD_FL)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+#endif
+
 /*
  * chattr's fsflags are unrelated to extended attributes,
  * but tmpfs has chosen to enable them under the same config option.
  */
-static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
+static int shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry)
 {
 	unsigned int i_flags = 0;
+	int ret;
+
+	ret = shmem_inode_casefold_flags(inode, fsflags, dentry, &i_flags);
+	if (ret)
+		return ret;
 
 	if (fsflags & FS_NOATIME_FL)
 		i_flags |= S_NOATIME;
@@ -2766,10 +2820,12 @@ static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
 	/*
 	 * But FS_NODUMP_FL does not require any action in i_flags.
 	 */
-	inode_set_flags(inode, i_flags, S_NOATIME | S_APPEND | S_IMMUTABLE);
+	inode_set_flags(inode, i_flags, S_NOATIME | S_APPEND | S_IMMUTABLE | S_CASEFOLD);
+
+	return 0;
 }
 #else
-static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags)
+static void shmem_set_inode_flags(struct inode *inode, unsigned int fsflags, struct dentry *dentry)
 {
 }
 #define shmem_initxattrs NULL
@@ -2816,7 +2872,7 @@ static struct inode *__shmem_get_inode(struct mnt_idmap *idmap,
 	info->fsflags = (dir == NULL) ? 0 :
 		SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED;
 	if (info->fsflags)
-		shmem_set_inode_flags(inode, info->fsflags);
+		shmem_set_inode_flags(inode, info->fsflags, NULL);
 	INIT_LIST_HEAD(&info->shrinklist);
 	INIT_LIST_HEAD(&info->swaplist);
 	simple_xattrs_init(&info->xattrs);
@@ -3562,6 +3618,9 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	struct inode *inode;
 	int error;
 
+	if (!generic_ci_validate_strict_name(dir, &dentry->d_name))
+		return -EINVAL;
+
 	inode = shmem_get_inode(idmap, dir->i_sb, dir, mode, dev, VM_NORESERVE);
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
@@ -3581,7 +3640,12 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir,
 	dir->i_size += BOGO_DIRENT_SIZE;
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	inode_inc_iversion(dir);
-	d_instantiate(dentry, inode);
+
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
+		d_add(dentry, inode);
+	else
+		d_instantiate(dentry, inode);
+
 	dget(dentry); /* Extra count - pin the dentry in core */
 	return error;
 
@@ -3672,7 +3736,10 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir,
 	inc_nlink(inode);
 	ihold(inode);	/* New dentry reference */
 	dget(dentry);	/* Extra pinning count for the created dentry */
-	d_instantiate(dentry, inode);
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
+		d_add(dentry, inode);
+	else
+		d_instantiate(dentry, inode);
 out:
 	return ret;
 }
@@ -3692,6 +3759,14 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
 	inode_inc_iversion(dir);
 	drop_nlink(inode);
 	dput(dentry);	/* Undo the count from "create" - does all the work */
+
+	/*
+	 * For now, VFS can't deal with case-insensitive negative dentries, so
+	 * we invalidate them
+	 */
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
+		d_invalidate(dentry);
+
 	return 0;
 }
 
@@ -3836,7 +3911,10 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir,
 	dir->i_size += BOGO_DIRENT_SIZE;
 	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
 	inode_inc_iversion(dir);
-	d_instantiate(dentry, inode);
+	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))
+		d_add(dentry, inode);
+	else
+		d_instantiate(dentry, inode);
 	dget(dentry);
 	return 0;
 
@@ -3901,16 +3979,23 @@ static int shmem_fileattr_set(struct mnt_idmap *idmap,
 {
 	struct inode *inode = d_inode(dentry);
 	struct shmem_inode_info *info = SHMEM_I(inode);
+	int ret, flags;
 
 	if (fileattr_has_fsx(fa))
 		return -EOPNOTSUPP;
 	if (fa->flags & ~SHMEM_FL_USER_MODIFIABLE)
 		return -EOPNOTSUPP;
 
-	info->fsflags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) |
+	flags = (info->fsflags & ~SHMEM_FL_USER_MODIFIABLE) |
 		(fa->flags & SHMEM_FL_USER_MODIFIABLE);
 
-	shmem_set_inode_flags(inode, info->fsflags);
+	ret = shmem_set_inode_flags(inode, flags, dentry);
+
+	if (ret)
+		return ret;
+
+	info->fsflags = flags;
+
 	inode_set_ctime_current(inode);
 	inode_inc_iversion(inode);
 	return 0;
@@ -4189,6 +4274,9 @@ enum shmem_param {
 	Opt_usrquota_inode_hardlimit,
 	Opt_grpquota_block_hardlimit,
 	Opt_grpquota_inode_hardlimit,
+	Opt_casefold_version,
+	Opt_casefold,
+	Opt_strict_encoding,
 };
 
 static const struct constant_table shmem_param_enums_huge[] = {
@@ -4220,9 +4308,54 @@ const struct fs_parameter_spec shmem_fs_parameters[] = {
 	fsparam_string("grpquota_block_hardlimit", Opt_grpquota_block_hardlimit),
 	fsparam_string("grpquota_inode_hardlimit", Opt_grpquota_inode_hardlimit),
 #endif
+	fsparam_string("casefold",	Opt_casefold_version),
+	fsparam_flag  ("casefold",	Opt_casefold),
+	fsparam_flag  ("strict_encoding", Opt_strict_encoding),
 	{}
 };
 
+#if IS_ENABLED(CONFIG_UNICODE)
+static int shmem_parse_opt_casefold(struct fs_context *fc, struct fs_parameter *param,
+				    bool latest_version)
+{
+	struct shmem_options *ctx = fc->fs_private;
+	unsigned int version = UTF8_LATEST;
+	struct unicode_map *encoding;
+	char *version_str = param->string + 5;
+
+	if (!latest_version) {
+		if (strncmp(param->string, "utf8-", 5))
+			return invalfc(fc, "Only UTF-8 encodings are supported "
+				       "in the format: utf8-<version number>");
+
+		version = utf8_parse_version(version_str);
+		if (version < 0)
+			return invalfc(fc, "Invalid UTF-8 version: %s", version_str);
+	}
+
+	encoding = utf8_load(version);
+
+	if (IS_ERR(encoding)) {
+		return invalfc(fc, "Failed loading UTF-8 version: utf8-%u.%u.%u\n",
+			       unicode_major(version), unicode_minor(version),
+			       unicode_rev(version));
+	}
+
+	pr_info("tmpfs: Using encoding : utf8-%u.%u.%u\n",
+		unicode_major(version), unicode_minor(version), unicode_rev(version));
+
+	ctx->encoding = encoding;
+
+	return 0;
+}
+#else
+static int shmem_parse_opt_casefold(struct fs_context *fc, struct fs_parameter *param,
+				    bool latest_version)
+{
+	return invalfc(fc, "tmpfs: Kernel not built with CONFIG_UNICODE\n");
+}
+#endif
+
 static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 {
 	struct shmem_options *ctx = fc->fs_private;
@@ -4381,6 +4514,17 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
 				       "Group quota inode hardlimit too large.");
 		ctx->qlimits.grpquota_ihardlimit = size;
 		break;
+	case Opt_casefold_version:
+		return shmem_parse_opt_casefold(fc, param, false);
+	case Opt_casefold:
+		return shmem_parse_opt_casefold(fc, param, true);
+	case Opt_strict_encoding:
+#if IS_ENABLED(CONFIG_UNICODE)
+		ctx->strict_encoding = true;
+		break;
+#else
+		return invalfc(fc, "tmpfs: Kernel not built with CONFIG_UNICODE\n");
+#endif
 	}
 	return 0;
 
@@ -4610,6 +4754,11 @@ static void shmem_put_super(struct super_block *sb)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 
+#if IS_ENABLED(CONFIG_UNICODE)
+	if (sb->s_encoding)
+		utf8_unload(sb->s_encoding);
+#endif
+
 #ifdef CONFIG_TMPFS_QUOTA
 	shmem_disable_quotas(sb);
 #endif
@@ -4620,6 +4769,14 @@ static void shmem_put_super(struct super_block *sb)
 	sb->s_fs_info = NULL;
 }
 
+#if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_TMPFS)
+static const struct dentry_operations shmem_ci_dentry_ops = {
+	.d_hash = generic_ci_d_hash,
+	.d_compare = generic_ci_d_compare,
+	.d_delete = always_delete_dentry,
+};
+#endif
+
 static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 {
 	struct shmem_options *ctx = fc->fs_private;
@@ -4654,9 +4811,25 @@ static int shmem_fill_super(struct super_block *sb, struct fs_context *fc)
 	}
 	sb->s_export_op = &shmem_export_ops;
 	sb->s_flags |= SB_NOSEC | SB_I_VERSION;
+
+#if IS_ENABLED(CONFIG_UNICODE)
+	if (!ctx->encoding && ctx->strict_encoding) {
+		pr_err("tmpfs: strict_encoding option without encoding is forbidden\n");
+		error = -EINVAL;
+		goto failed;
+	}
+
+	if (ctx->encoding) {
+		sb->s_encoding = ctx->encoding;
+		sb->s_d_op = &shmem_ci_dentry_ops;
+		if (ctx->strict_encoding)
+			sb->s_encoding_flags = SB_ENC_STRICT_MODE_FL;
+	}
+#endif
+
 #else
 	sb->s_flags |= SB_NOUSER;
-#endif
+#endif /* CONFIG_TMPFS */
 	sbinfo->max_blocks = ctx->blocks;
 	sbinfo->max_inodes = ctx->inodes;
 	sbinfo->free_ispace = sbinfo->max_inodes * BOGO_INODE_SIZE;
@@ -4930,6 +5103,10 @@ int shmem_init_fs_context(struct fs_context *fc)
 	ctx->uid = current_fsuid();
 	ctx->gid = current_fsgid();
 
+#if IS_ENABLED(CONFIG_UNICODE)
+	ctx->encoding = NULL;
+#endif
+
 	fc->fs_private = ctx;
 	fc->ops = &shmem_fs_context_ops;
 	return 0;
@@ -4946,6 +5123,66 @@ static struct file_system_type shmem_fs_type = {
 	.fs_flags	= FS_USERNS_MOUNT | FS_ALLOW_IDMAP | FS_MGTIME,
 };
 
+#if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS)
+
+#define __INIT_KOBJ_ATTR(_name, _mode, _show, _store)			\
+{									\
+	.attr	= { .name = __stringify(_name), .mode = _mode },	\
+	.show	= _show,						\
+	.store	= _store,						\
+}
+
+#define TMPFS_ATTR_W(_name, _store)				\
+	static struct kobj_attribute tmpfs_attr_##_name =	\
+			__INIT_KOBJ_ATTR(_name, 0200, NULL, _store)
+
+#define TMPFS_ATTR_RW(_name, _show, _store)			\
+	static struct kobj_attribute tmpfs_attr_##_name =	\
+			__INIT_KOBJ_ATTR(_name, 0644, _show, _store)
+
+#define TMPFS_ATTR_RO(_name, _show)				\
+	static struct kobj_attribute tmpfs_attr_##_name =	\
+			__INIT_KOBJ_ATTR(_name, 0444, _show, NULL)
+
+#if IS_ENABLED(CONFIG_UNICODE)
+static ssize_t casefold_show(struct kobject *kobj, struct kobj_attribute *a,
+			char *buf)
+{
+		return sysfs_emit(buf, "supported\n");
+}
+TMPFS_ATTR_RO(casefold, casefold_show);
+#endif
+
+static struct attribute *tmpfs_attributes[] = {
+#if IS_ENABLED(CONFIG_UNICODE)
+	&tmpfs_attr_casefold.attr,
+#endif
+	NULL
+};
+
+static const struct attribute_group tmpfs_attribute_group = {
+	.attrs = tmpfs_attributes,
+	.name = "features"
+};
+
+static struct kobject *tmpfs_kobj;
+
+static int __init tmpfs_sysfs_init(void)
+{
+	int ret;
+
+	tmpfs_kobj = kobject_create_and_add("tmpfs", fs_kobj);
+	if (!tmpfs_kobj)
+		return -ENOMEM;
+
+	ret = sysfs_create_group(tmpfs_kobj, &tmpfs_attribute_group);
+	if (ret)
+		kobject_put(tmpfs_kobj);
+
+	return ret;
+}
+#endif /* CONFIG_SYSFS && CONFIG_TMPFS */
+
 void __init shmem_init(void)
 {
 	int error;
@@ -4969,6 +5206,14 @@ void __init shmem_init(void)
 		goto out1;
 	}
 
+#if defined(CONFIG_SYSFS) && defined(CONFIG_TMPFS)
+	error = tmpfs_sysfs_init();
+	if (error) {
+		pr_err("Could not init tmpfs sysfs\n");
+		goto out1;
+	}
+#endif
+
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 	if (has_transparent_hugepage() && shmem_huge > SHMEM_HUGE_DENY)
 		SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge;