From be7efb2d20d67f334a7de2aef77ae6c69367e646 Mon Sep 17 00:00:00 2001 From: Andrey Albershteyn Date: Mon, 30 Jun 2025 18:20:16 +0200 Subject: fs: introduce file_getattr and file_setattr syscalls Introduce file_getattr() and file_setattr() syscalls to manipulate inode extended attributes. The syscalls takes pair of file descriptor and pathname. Then it operates on inode opened accroding to openat() semantics. The struct file_attr is passed to obtain/change extended attributes. This is an alternative to FS_IOC_FSSETXATTR ioctl with a difference that file don't need to be open as we can reference it with a path instead of fd. By having this we can manipulated inode extended attributes not only on regular files but also on special ones. This is not possible with FS_IOC_FSSETXATTR ioctl as with special files we can not call ioctl() directly on the filesystem inode using fd. This patch adds two new syscalls which allows userspace to get/set extended inode attributes on special files by using parent directory and a path - *at() like syscall. CC: linux-api@vger.kernel.org CC: linux-fsdevel@vger.kernel.org CC: linux-xfs@vger.kernel.org Signed-off-by: Andrey Albershteyn Link: https://lore.kernel.org/20250630-xattrat-syscall-v6-6-c4e3bc35227b@kernel.org Acked-by: Arnd Bergmann Signed-off-by: Christian Brauner --- include/linux/syscalls.h | 7 +++++++ include/uapi/asm-generic/unistd.h | 8 +++++++- include/uapi/linux/fs.h | 18 ++++++++++++++++++ 3 files changed, 32 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e5603cc91963..77f45e5d4413 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -78,6 +78,7 @@ struct cachestat; struct statmount; struct mnt_id_req; struct xattr_args; +struct file_attr; #include #include @@ -371,6 +372,12 @@ asmlinkage long sys_removexattrat(int dfd, const char __user *path, asmlinkage long sys_lremovexattr(const char __user *path, const char __user *name); asmlinkage long sys_fremovexattr(int fd, const char __user *name); +asmlinkage long sys_file_getattr(int dfd, const char __user *filename, + struct file_attr __user *attr, size_t usize, + unsigned int at_flags); +asmlinkage long sys_file_setattr(int dfd, const char __user *filename, + struct file_attr __user *attr, size_t usize, + unsigned int at_flags); asmlinkage long sys_getcwd(char __user *buf, unsigned long size); asmlinkage long sys_eventfd2(unsigned int count, int flags); asmlinkage long sys_epoll_create1(int flags); diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h index 2892a45023af..04e0077fb4c9 100644 --- a/include/uapi/asm-generic/unistd.h +++ b/include/uapi/asm-generic/unistd.h @@ -852,8 +852,14 @@ __SYSCALL(__NR_removexattrat, sys_removexattrat) #define __NR_open_tree_attr 467 __SYSCALL(__NR_open_tree_attr, sys_open_tree_attr) +/* fs/inode.c */ +#define __NR_file_getattr 468 +__SYSCALL(__NR_file_getattr, sys_file_getattr) +#define __NR_file_setattr 469 +__SYSCALL(__NR_file_setattr, sys_file_setattr) + #undef __NR_syscalls -#define __NR_syscalls 468 +#define __NR_syscalls 470 /* * 32 bit systems traditionally used different diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index 0098b0ce8ccb..9663dbdda181 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -148,6 +148,24 @@ struct fsxattr { unsigned char fsx_pad[8]; }; +/* + * Variable size structure for file_[sg]et_attr(). + * + * Note. This is alternative to the structure 'struct fileattr'/'struct fsxattr'. + * As this structure is passed to/from userspace with its size, this can + * be versioned based on the size. + */ +struct file_attr { + __u64 fa_xflags; /* xflags field value (get/set) */ + __u32 fa_extsize; /* extsize field value (get/set)*/ + __u32 fa_nextents; /* nextents field value (get) */ + __u32 fa_projid; /* project identifier (get/set) */ + __u32 fa_cowextsize; /* CoW extsize field value (get/set) */ +}; + +#define FILE_ATTR_SIZE_VER0 24 +#define FILE_ATTR_SIZE_LATEST FILE_ATTR_SIZE_VER0 + /* * Flags for the fsx_xflags field */ -- cgit v1.2.3