From ab90c2d2476c4dd6deddd089c7e83b858d135783 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 10 Aug 2025 00:57:00 -0700 Subject: [PATCH] fs: remove inode::i_crypt_info Now that all fscrypt-capable filesystems store the pointer to fscrypt_inode_info in the filesystem-specific part of the inode structure, inode::i_crypt_info is no longer needed. Update fscrypt_inode_info_addr() to no longer support the fallback to inode::i_crypt_info. Finally, remove inode::i_crypt_info itself along with the now-unnecessary forward declaration of fscrypt_inode_info. The end result of the migration to the filesystem-specific pointer is memory savings on CONFIG_FS_ENCRYPTION=y kernels for all filesystems that don't support fscrypt. Specifically, their in-memory inodes are now smaller by the size of a pointer: either 4 or 8 bytes. Co-developed-by: Christian Brauner Signed-off-by: Eric Biggers Link: https://lore.kernel.org/20250810075706.172910-8-ebiggers@kernel.org Signed-off-by: Christian Brauner --- include/linux/fs.h | 5 ----- include/linux/fscrypt.h | 8 ++++++-- 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index d7ab4f96d7051..1dafa18169be6 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -72,7 +72,6 @@ struct swap_info_struct; struct seq_file; struct workqueue_struct; struct iov_iter; -struct fscrypt_inode_info; struct fscrypt_operations; struct fsverity_info; struct fsverity_operations; @@ -780,10 +779,6 @@ struct inode { struct fsnotify_mark_connector __rcu *i_fsnotify_marks; #endif -#ifdef CONFIG_FS_ENCRYPTION - struct fscrypt_inode_info *i_crypt_info; -#endif - #ifdef CONFIG_FS_VERITY struct fsverity_info *i_verity_info; #endif diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index d7ff53accbfef..516aba5b858b5 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -201,11 +201,15 @@ struct fscrypt_operations { int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, struct dentry *dentry, unsigned int flags); +/* + * Returns the address of the fscrypt info pointer within the + * filesystem-specific part of the inode. (To save memory on filesystems that + * don't support fscrypt, a field in 'struct inode' itself is no longer used.) + */ static inline struct fscrypt_inode_info ** fscrypt_inode_info_addr(const struct inode *inode) { - if (inode->i_sb->s_cop->inode_info_offs == 0) - return (struct fscrypt_inode_info **)&inode->i_crypt_info; + VFS_WARN_ON_ONCE(inode->i_sb->s_cop->inode_info_offs == 0); return (void *)inode + inode->i_sb->s_cop->inode_info_offs; } -- 2.47.3