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Commit 12f169fd authored by Eric Biggers's avatar Eric Biggers Committed by Jaegeuk Kim
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fs, fscrypt: add an S_ENCRYPTED inode flag 



Introduce a flag S_ENCRYPTED which can be set in ->i_flags to indicate
that the inode is encrypted using the fscrypt (fs/crypto/) mechanism.

Checking this flag will give the same information that
inode->i_sb->s_cop->is_encrypted(inode) currently does, but will be more
efficient.  This will be useful for adding higher-level helper functions
for filesystems to use.  For example we'll be able to replace this:

	if (ext4_encrypted_inode(inode)) {
		ret = fscrypt_get_encryption_info(inode);
		if (ret)
			return ret;
		if (!fscrypt_has_encryption_key(inode))
			return -ENOKEY;
	}

with this:

	ret = fscrypt_require_key(inode);
	if (ret)
		return ret;

... since we'll be able to retain the fast path for unencrypted files as
a single flag check, using an inline function.  This wasn't possible
before because we'd have had to frequently call through the
->i_sb->s_cop->is_encrypted function pointer, even when the encryption
support was disabled or not being used.

Note: we don't define S_ENCRYPTED to 0 if CONFIG_FS_ENCRYPTION is
disabled because we want to continue to return an error if an encrypted
file is accessed without encryption support, rather than pretending that
it is unencrypted.

Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Acked-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 0f461ce2

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -3181,6 +3181,7 @@ static inline void f2fs_set_encrypted_inode(struct inode *inode) 
{

#ifdef CONFIG_F2FS_FS_ENCRYPTION

	file_set_encrypt(inode);

	inode->i_flags |= S_ENCRYPTED;

#endif

}

fs/f2fs/inode.c

+4 −1
Original line number Diff line number Diff line
@@ -43,8 +43,11 @@ void f2fs_set_inode_flags(struct inode *inode) 
		new_fl |= S_NOATIME;

	if (flags & FS_DIRSYNC_FL)

		new_fl |= S_DIRSYNC;

	if (f2fs_encrypted_inode(inode))

		new_fl |= S_ENCRYPTED;

	inode_set_flags(inode, new_fl,

			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);

			S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|

			S_ENCRYPTED);

}



static void __get_inode_rdev(struct inode *inode, struct f2fs_inode *ri)

include/linux/fs.h

+2 −0
Original line number Diff line number Diff line
@@ -1619,6 +1619,7 @@ struct super_operations { 
#define S_IMA		1024	/* Inode has an associated IMA struct */

#define S_AUTOMOUNT	2048	/* Automount/referral quasi-directory */

#define S_NOSEC		4096	/* no suid or xattr security attributes */

#define S_ENCRYPTED	16384	/* Encrypted file (using fs/crypto/) */



/*

 * Note that nosuid etc flags are inode-specific: setting some file-system
@@ -1656,6 +1657,7 @@ struct super_operations { 
#define IS_IMA(inode)		((inode)->i_flags & S_IMA)

#define IS_AUTOMOUNT(inode)	((inode)->i_flags & S_AUTOMOUNT)

#define IS_NOSEC(inode)		((inode)->i_flags & S_NOSEC)

#define IS_ENCRYPTED(inode)	((inode)->i_flags & S_ENCRYPTED)



#define IS_WHITEOUT(inode)	(S_ISCHR(inode->i_mode) && \

				 (inode)->i_rdev == WHITEOUT_DEV)