ext4: implemet new ioctls to set and get superblock parameters

Implement the EXT4_IOC_GET_TUNE_SB_PARAM and
EXT4_IOC_SET_TUNE_SB_PARAM ioctls, which allow certains superblock
parameters to be set while the file system is mounted, without needing
write access to the block device.

Reviewed-by: Darrick J. Wong <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
Message-ID: <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>

Author: tytso

fs/ext4/ioctl.c

@@ -27,14 +27,16 @@
 #include "fsmap.h"
 #include <trace/events/ext4.h>
 
-typedef void ext4_update_sb_callback(struct ext4_super_block *es,
-				       const void *arg);
+typedef void ext4_update_sb_callback(struct ext4_sb_info *sbi,
+				     struct ext4_super_block *es,
+				     const void *arg);
 
 /*
  * Superblock modification callback function for changing file system
  * label
  */
-static void ext4_sb_setlabel(struct ext4_super_block *es, const void *arg)
+static void ext4_sb_setlabel(struct ext4_sb_info *sbi,
+			     struct ext4_super_block *es, const void *arg)
 {
 	/* Sanity check, this should never happen */
 	BUILD_BUG_ON(sizeof(es->s_volume_name) < EXT4_LABEL_MAX);
@@ -46,7 +48,8 @@ static void ext4_sb_setlabel(struct ext4_super_block *es, const void *arg)
  * Superblock modification callback function for changing file system
  * UUID.
  */
-static void ext4_sb_setuuid(struct ext4_super_block *es, const void *arg)
+static void ext4_sb_setuuid(struct ext4_sb_info *sbi,
+			    struct ext4_super_block *es, const void *arg)
 {
 	memcpy(es->s_uuid, (__u8 *)arg, UUID_SIZE);
 }
@@ -71,7 +74,7 @@ int ext4_update_primary_sb(struct super_block *sb, handle_t *handle,
 		goto out_err;
 
 	lock_buffer(bh);
-	func(es, arg);
+	func(sbi, es, arg);
 	ext4_superblock_csum_set(sb);
 	unlock_buffer(bh);
 
@@ -149,7 +152,7 @@ static int ext4_update_backup_sb(struct super_block *sb,
 		unlock_buffer(bh);
 		goto out_bh;
 	}
-	func(es, arg);
+	func(EXT4_SB(sb), es, arg);
 	if (ext4_has_feature_metadata_csum(sb))
 		es->s_checksum = ext4_superblock_csum(es);
 	set_buffer_uptodate(bh);
@@ -1230,6 +1233,295 @@ static int ext4_ioctl_setuuid(struct file *filp,
 	return ret;
 }
 
+
+#define TUNE_OPS_SUPPORTED (EXT4_TUNE_FL_ERRORS_BEHAVIOR |    \
+	EXT4_TUNE_FL_MNT_COUNT | EXT4_TUNE_FL_MAX_MNT_COUNT | \
+	EXT4_TUNE_FL_CHECKINTRVAL | EXT4_TUNE_FL_LAST_CHECK_TIME | \
+	EXT4_TUNE_FL_RESERVED_BLOCKS | EXT4_TUNE_FL_RESERVED_UID | \
+	EXT4_TUNE_FL_RESERVED_GID | EXT4_TUNE_FL_DEFAULT_MNT_OPTS | \
+	EXT4_TUNE_FL_DEF_HASH_ALG | EXT4_TUNE_FL_RAID_STRIDE | \
+	EXT4_TUNE_FL_RAID_STRIPE_WIDTH | EXT4_TUNE_FL_MOUNT_OPTS | \
+	EXT4_TUNE_FL_FEATURES | EXT4_TUNE_FL_EDIT_FEATURES | \
+	EXT4_TUNE_FL_FORCE_FSCK | EXT4_TUNE_FL_ENCODING | \
+	EXT4_TUNE_FL_ENCODING_FLAGS)
+
+#define EXT4_TUNE_SET_COMPAT_SUPP \
+		(EXT4_FEATURE_COMPAT_DIR_INDEX |	\
+		 EXT4_FEATURE_COMPAT_STABLE_INODES)
+#define EXT4_TUNE_SET_INCOMPAT_SUPP \
+		(EXT4_FEATURE_INCOMPAT_EXTENTS |	\
+		 EXT4_FEATURE_INCOMPAT_EA_INODE |	\
+		 EXT4_FEATURE_INCOMPAT_ENCRYPT |	\
+		 EXT4_FEATURE_INCOMPAT_CSUM_SEED |	\
+		 EXT4_FEATURE_INCOMPAT_LARGEDIR |	\
+		 EXT4_FEATURE_INCOMPAT_CASEFOLD)
+#define EXT4_TUNE_SET_RO_COMPAT_SUPP \
+		(EXT4_FEATURE_RO_COMPAT_LARGE_FILE |	\
+		 EXT4_FEATURE_RO_COMPAT_DIR_NLINK |	\
+		 EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE |	\
+		 EXT4_FEATURE_RO_COMPAT_PROJECT |	\
+		 EXT4_FEATURE_RO_COMPAT_VERITY)
+
+#define EXT4_TUNE_CLEAR_COMPAT_SUPP (0)
+#define EXT4_TUNE_CLEAR_INCOMPAT_SUPP (0)
+#define EXT4_TUNE_CLEAR_RO_COMPAT_SUPP (0)
+
+#define SB_ENC_SUPP_MASK (SB_ENC_STRICT_MODE_FL |	\
+			  SB_ENC_NO_COMPAT_FALLBACK_FL)
+
+static int ext4_ioctl_get_tune_sb(struct ext4_sb_info *sbi,
+				  struct ext4_tune_sb_params __user *params)
+{
+	struct ext4_tune_sb_params ret;
+	struct ext4_super_block *es = sbi->s_es;
+
+	memset(&ret, 0, sizeof(ret));
+	ret.set_flags = TUNE_OPS_SUPPORTED;
+	ret.errors_behavior = le16_to_cpu(es->s_errors);
+	ret.mnt_count = le16_to_cpu(es->s_mnt_count);
+	ret.max_mnt_count = le16_to_cpu(es->s_max_mnt_count);
+	ret.checkinterval = le32_to_cpu(es->s_checkinterval);
+	ret.last_check_time = le32_to_cpu(es->s_lastcheck);
+	ret.reserved_blocks = ext4_r_blocks_count(es);
+	ret.blocks_count = ext4_blocks_count(es);
+	ret.reserved_uid = ext4_get_resuid(es);
+	ret.reserved_gid = ext4_get_resgid(es);
+	ret.default_mnt_opts = le32_to_cpu(es->s_default_mount_opts);
+	ret.def_hash_alg = es->s_def_hash_version;
+	ret.raid_stride = le16_to_cpu(es->s_raid_stride);
+	ret.raid_stripe_width = le32_to_cpu(es->s_raid_stripe_width);
+	ret.encoding = le16_to_cpu(es->s_encoding);
+	ret.encoding_flags = le16_to_cpu(es->s_encoding_flags);
+	strscpy_pad(ret.mount_opts, es->s_mount_opts);
+	ret.feature_compat = le32_to_cpu(es->s_feature_compat);
+	ret.feature_incompat = le32_to_cpu(es->s_feature_incompat);
+	ret.feature_ro_compat = le32_to_cpu(es->s_feature_ro_compat);
+	ret.set_feature_compat_mask = EXT4_TUNE_SET_COMPAT_SUPP;
+	ret.set_feature_incompat_mask = EXT4_TUNE_SET_INCOMPAT_SUPP;
+	ret.set_feature_ro_compat_mask = EXT4_TUNE_SET_RO_COMPAT_SUPP;
+	ret.clear_feature_compat_mask = EXT4_TUNE_CLEAR_COMPAT_SUPP;
+	ret.clear_feature_incompat_mask = EXT4_TUNE_CLEAR_INCOMPAT_SUPP;
+	ret.clear_feature_ro_compat_mask = EXT4_TUNE_CLEAR_RO_COMPAT_SUPP;
+	if (copy_to_user(params, &ret, sizeof(ret)))
+		return -EFAULT;
+	return 0;
+}
+
+static void ext4_sb_setparams(struct ext4_sb_info *sbi,
+			      struct ext4_super_block *es, const void *arg)
+{
+	const struct ext4_tune_sb_params *params = arg;
+
+	if (params->set_flags & EXT4_TUNE_FL_ERRORS_BEHAVIOR)
+		es->s_errors = cpu_to_le16(params->errors_behavior);
+	if (params->set_flags & EXT4_TUNE_FL_MNT_COUNT)
+		es->s_mnt_count = cpu_to_le16(params->mnt_count);
+	if (params->set_flags & EXT4_TUNE_FL_MAX_MNT_COUNT)
+		es->s_max_mnt_count = cpu_to_le16(params->max_mnt_count);
+	if (params->set_flags & EXT4_TUNE_FL_CHECKINTRVAL)
+		es->s_checkinterval = cpu_to_le32(params->checkinterval);
+	if (params->set_flags & EXT4_TUNE_FL_LAST_CHECK_TIME)
+		es->s_lastcheck = cpu_to_le32(params->last_check_time);
+	if (params->set_flags & EXT4_TUNE_FL_RESERVED_BLOCKS) {
+		ext4_fsblk_t blk = params->reserved_blocks;
+
+		es->s_r_blocks_count_lo = cpu_to_le32((u32)blk);
+		es->s_r_blocks_count_hi = cpu_to_le32(blk >> 32);
+	}
+	if (params->set_flags & EXT4_TUNE_FL_RESERVED_UID) {
+		int uid = params->reserved_uid;
+
+		es->s_def_resuid = cpu_to_le16(uid & 0xFFFF);
+		es->s_def_resuid_hi = cpu_to_le16(uid >> 16);
+	}
+	if (params->set_flags & EXT4_TUNE_FL_RESERVED_GID) {
+		int gid = params->reserved_gid;
+
+		es->s_def_resgid = cpu_to_le16(gid & 0xFFFF);
+		es->s_def_resgid_hi = cpu_to_le16(gid >> 16);
+	}
+	if (params->set_flags & EXT4_TUNE_FL_DEFAULT_MNT_OPTS)
+		es->s_default_mount_opts = cpu_to_le32(params->default_mnt_opts);
+	if (params->set_flags & EXT4_TUNE_FL_DEF_HASH_ALG)
+		es->s_def_hash_version = params->def_hash_alg;
+	if (params->set_flags & EXT4_TUNE_FL_RAID_STRIDE)
+		es->s_raid_stride = cpu_to_le16(params->raid_stride);
+	if (params->set_flags & EXT4_TUNE_FL_RAID_STRIPE_WIDTH)
+		es->s_raid_stripe_width =
+			cpu_to_le32(params->raid_stripe_width);
+	if (params->set_flags & EXT4_TUNE_FL_ENCODING)
+		es->s_encoding = cpu_to_le16(params->encoding);
+	if (params->set_flags & EXT4_TUNE_FL_ENCODING_FLAGS)
+		es->s_encoding_flags = cpu_to_le16(params->encoding_flags);
+	strscpy_pad(es->s_mount_opts, params->mount_opts);
+	if (params->set_flags & EXT4_TUNE_FL_EDIT_FEATURES) {
+		es->s_feature_compat |=
+			cpu_to_le32(params->set_feature_compat_mask);
+		es->s_feature_incompat |=
+			cpu_to_le32(params->set_feature_incompat_mask);
+		es->s_feature_ro_compat |=
+			cpu_to_le32(params->set_feature_ro_compat_mask);
+		es->s_feature_compat &=
+			~cpu_to_le32(params->clear_feature_compat_mask);
+		es->s_feature_incompat &=
+			~cpu_to_le32(params->clear_feature_incompat_mask);
+		es->s_feature_ro_compat &=
+			~cpu_to_le32(params->clear_feature_ro_compat_mask);
+		if (params->set_feature_compat_mask &
+		    EXT4_FEATURE_COMPAT_DIR_INDEX)
+			es->s_def_hash_version = sbi->s_def_hash_version;
+		if (params->set_feature_incompat_mask &
+		    EXT4_FEATURE_INCOMPAT_CSUM_SEED)
+			es->s_checksum_seed = cpu_to_le32(sbi->s_csum_seed);
+	}
+	if (params->set_flags & EXT4_TUNE_FL_FORCE_FSCK)
+		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
+}
+
+static int ext4_ioctl_set_tune_sb(struct file *filp,
+				  struct ext4_tune_sb_params __user *in)
+{
+	struct ext4_tune_sb_params params;
+	struct super_block *sb = file_inode(filp)->i_sb;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int enabling_casefold = 0;
+	int ret;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (copy_from_user(&params, in, sizeof(params)))
+		return -EFAULT;
+
+	if ((params.set_flags & ~TUNE_OPS_SUPPORTED) != 0)
+		return -EOPNOTSUPP;
+
+	if ((params.set_flags & EXT4_TUNE_FL_ERRORS_BEHAVIOR) &&
+	    (params.errors_behavior > EXT4_ERRORS_PANIC))
+		return -EINVAL;
+
+	if ((params.set_flags & EXT4_TUNE_FL_RESERVED_BLOCKS) &&
+	    (params.reserved_blocks > ext4_blocks_count(sbi->s_es) / 2))
+		return -EINVAL;
+	if ((params.set_flags & EXT4_TUNE_FL_DEF_HASH_ALG) &&
+	    ((params.def_hash_alg > DX_HASH_LAST) ||
+	     (params.def_hash_alg == DX_HASH_SIPHASH)))
+		return -EINVAL;
+	if ((params.set_flags & EXT4_TUNE_FL_FEATURES) &&
+	    (params.set_flags & EXT4_TUNE_FL_EDIT_FEATURES))
+		return -EINVAL;
+
+	if (params.set_flags & EXT4_TUNE_FL_FEATURES) {
+		params.set_feature_compat_mask =
+			params.feature_compat &
+			~le32_to_cpu(es->s_feature_compat);
+		params.set_feature_incompat_mask =
+			params.feature_incompat &
+			~le32_to_cpu(es->s_feature_incompat);
+		params.set_feature_ro_compat_mask =
+			params.feature_ro_compat &
+			~le32_to_cpu(es->s_feature_ro_compat);
+		params.clear_feature_compat_mask =
+			~params.feature_compat &
+			le32_to_cpu(es->s_feature_compat);
+		params.clear_feature_incompat_mask =
+			~params.feature_incompat &
+			le32_to_cpu(es->s_feature_incompat);
+		params.clear_feature_ro_compat_mask =
+			~params.feature_ro_compat &
+			le32_to_cpu(es->s_feature_ro_compat);
+		params.set_flags |= EXT4_TUNE_FL_EDIT_FEATURES;
+	}
+	if (params.set_flags & EXT4_TUNE_FL_EDIT_FEATURES) {
+		if ((params.set_feature_compat_mask &
+		     ~EXT4_TUNE_SET_COMPAT_SUPP) ||
+		    (params.set_feature_incompat_mask &
+		     ~EXT4_TUNE_SET_INCOMPAT_SUPP) ||
+		    (params.set_feature_ro_compat_mask &
+		     ~EXT4_TUNE_SET_RO_COMPAT_SUPP) ||
+		    (params.clear_feature_compat_mask &
+		     ~EXT4_TUNE_CLEAR_COMPAT_SUPP) ||
+		    (params.clear_feature_incompat_mask &
+		     ~EXT4_TUNE_CLEAR_INCOMPAT_SUPP) ||
+		    (params.clear_feature_ro_compat_mask &
+		     ~EXT4_TUNE_CLEAR_RO_COMPAT_SUPP))
+			return -EOPNOTSUPP;
+
+		/*
+		 * Filter out the features that are already set from
+		 * the set_mask.
+		 */
+		params.set_feature_compat_mask &=
+			~le32_to_cpu(es->s_feature_compat);
+		params.set_feature_incompat_mask &=
+			~le32_to_cpu(es->s_feature_incompat);
+		params.set_feature_ro_compat_mask &=
+			~le32_to_cpu(es->s_feature_ro_compat);
+		if ((params.set_feature_incompat_mask &
+		     EXT4_FEATURE_INCOMPAT_CASEFOLD)) {
+			enabling_casefold = 1;
+			if (!(params.set_flags & EXT4_TUNE_FL_ENCODING)) {
+				params.encoding = EXT4_ENC_UTF8_12_1;
+				params.set_flags |= EXT4_TUNE_FL_ENCODING;
+			}
+			if (!(params.set_flags & EXT4_TUNE_FL_ENCODING_FLAGS)) {
+				params.encoding_flags = 0;
+				params.set_flags |= EXT4_TUNE_FL_ENCODING_FLAGS;
+			}
+		}
+		if ((params.set_feature_compat_mask &
+		     EXT4_FEATURE_COMPAT_DIR_INDEX)) {
+			uuid_t	uu;
+
+			memcpy(&uu, sbi->s_hash_seed, UUID_SIZE);
+			if (uuid_is_null(&uu))
+				generate_random_uuid((char *)
+						     &sbi->s_hash_seed);
+			if (params.set_flags & EXT4_TUNE_FL_DEF_HASH_ALG)
+				sbi->s_def_hash_version = params.def_hash_alg;
+			else if (sbi->s_def_hash_version == 0)
+				sbi->s_def_hash_version = DX_HASH_HALF_MD4;
+			if (!(es->s_flags &
+			      cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH)) &&
+			    !(es->s_flags &
+			      cpu_to_le32(EXT2_FLAGS_SIGNED_HASH))) {
+#ifdef __CHAR_UNSIGNED__
+				sbi->s_hash_unsigned = 3;
+#else
+				sbi->s_hash_unsigned = 0;
+#endif
+			}
+		}
+	}
+	if (params.set_flags & EXT4_TUNE_FL_ENCODING) {
+		if (!enabling_casefold)
+			return -EINVAL;
+		if (params.encoding == 0)
+			params.encoding = EXT4_ENC_UTF8_12_1;
+		else if (params.encoding != EXT4_ENC_UTF8_12_1)
+			return -EINVAL;
+	}
+	if (params.set_flags & EXT4_TUNE_FL_ENCODING_FLAGS) {
+		if (!enabling_casefold)
+			return -EINVAL;
+		if (params.encoding_flags & ~SB_ENC_SUPP_MASK)
+			return -EINVAL;
+	}
+
+	ret = mnt_want_write_file(filp);
+	if (ret)
+		return ret;
+
+	ret = ext4_update_superblocks_fn(sb, ext4_sb_setparams, &params);
+	mnt_drop_write_file(filp);
+
+	if (params.set_flags & EXT4_TUNE_FL_DEF_HASH_ALG)
+		sbi->s_def_hash_version = params.def_hash_alg;
+
+	return ret;
+}
+
 static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = file_inode(filp);
@@ -1616,6 +1908,11 @@ static long __ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		return ext4_ioctl_getuuid(EXT4_SB(sb), (void __user *)arg);
 	case EXT4_IOC_SETFSUUID:
 		return ext4_ioctl_setuuid(filp, (const void __user *)arg);
+	case EXT4_IOC_GET_TUNE_SB_PARAM:
+		return ext4_ioctl_get_tune_sb(EXT4_SB(sb),
+					      (void __user *)arg);
+	case EXT4_IOC_SET_TUNE_SB_PARAM:
+		return ext4_ioctl_set_tune_sb(filp, (void __user *)arg);
 	default:
 		return -ENOTTY;
 	}
@@ -1703,7 +2000,8 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 }
 #endif
 
-static void set_overhead(struct ext4_super_block *es, const void *arg)
+static void set_overhead(struct ext4_sb_info *sbi,
+			 struct ext4_super_block *es, const void *arg)
 {
 	es->s_overhead_clusters = cpu_to_le32(*((unsigned long *) arg));
 }