Hi, I came upon this "Ability to only open regular files" uapi feature suggestion from https://uapi-group.org/kernel-features/#ability-to-only-open-regular-files and thought it would be something I could do as a first patch and get to know the kernel code a bit better.
I only tested this new flag on my local system (fedora btrfs). Note that I had submitted a v4 previously (that had -EINVAL for the atomic_open code paths) but did not do a get_maintainers.pl. It didn't get any review and please ignore that one anyway. In this version, I have tried to properly update the filesystems that provide atomic_open (fs/ceph, fs/nfs, fs/smb, fs/gfs2, fs/fuse, fs/vboxsf, fs/9p) for the new OPENAT2_REGULAR flag. Some of them (fs/fuse, fs/vboxsf, fs/9p) didn't need any changing. As far as I see, most of the filesystems do finish_no_open for ~O_CREAT and have file->f_mode |= FMODE_CREATED for the O_CREAT code path which I assume means they always create new file which is a regular file. OPENAT2_REGULAR | O_DIRECTORY returns -EINVAL (instead of working if path is either a directory or regular file) as it was easier to reason about when making changes in all the filesystems. Changes in v4: - changed O_REGULAR to OPENAT2_REGULAR - OPENAT2_REGULAR does not affect O_PATH - atomic_open codepaths updated to work properly for OPENAT2_REGULAR - commit message includes the uapi-group URL - v3 is at: https://lore.kernel.org/linux-fsdevel/[email protected]/T/ Changes in v3: - included motivation about O_REGULAR flag in commit message e.g., programs not wanting to be tricked into opening device nodes - fixed commit message wrongly referencing ENOTREGULAR instead of ENOTREG - fixed the O_REGULAR flag in arch/parisc/include/uapi/asm/fcntl.h from 060000000 to 0100000000 - added 2 commits converting arch/{mips,sparc}/include/uapi/asm/fcntl.h O_* macros from hex to octal - v2 is at: https://lore.kernel.org/linux-fsdevel/[email protected]/T/ Changes in v2: - rename ENOTREGULAR to ENOTREG - define ENOTREG in uapi/asm-generic/errno.h (instead of errno-base.h) and in arch/*/include/uapi/asm/errno.h files - override O_REGULAR in arch/{alpha,sparc,parisc}/include/uapi/asm/fcntl.h due to clash with include/uapi/asm-generic/fcntl.h - I have kept the kselftest but now that O_REGULAR and ENOTREG can have different value on different architectures I am not sure if it's right - v1 is at: https://lore.kernel.org/linux-fsdevel/[email protected]/T/ Thanks. Regards, Dorjoy Dorjoy Chowdhury (4): openat2: new OPENAT2_REGULAR flag support kselftest/openat2: test for OPENAT2_REGULAR flag sparc/fcntl.h: convert O_* flag macros from hex to octal mips/fcntl.h: convert O_* flag macros from hex to octal arch/alpha/include/uapi/asm/errno.h | 2 + arch/alpha/include/uapi/asm/fcntl.h | 1 + arch/mips/include/uapi/asm/errno.h | 2 + arch/mips/include/uapi/asm/fcntl.h | 22 +++++------ arch/parisc/include/uapi/asm/errno.h | 2 + arch/parisc/include/uapi/asm/fcntl.h | 1 + arch/sparc/include/uapi/asm/errno.h | 2 + arch/sparc/include/uapi/asm/fcntl.h | 35 +++++++++--------- fs/ceph/file.c | 4 ++ fs/gfs2/inode.c | 2 + fs/namei.c | 4 ++ fs/nfs/dir.c | 4 +- fs/open.c | 4 +- fs/smb/client/dir.c | 11 +++++- include/linux/fcntl.h | 2 + include/uapi/asm-generic/errno.h | 2 + include/uapi/asm-generic/fcntl.h | 4 ++ tools/arch/alpha/include/uapi/asm/errno.h | 2 + tools/arch/mips/include/uapi/asm/errno.h | 2 + tools/arch/parisc/include/uapi/asm/errno.h | 2 + tools/arch/sparc/include/uapi/asm/errno.h | 2 + tools/include/uapi/asm-generic/errno.h | 2 + .../testing/selftests/openat2/openat2_test.c | 37 ++++++++++++++++++- 23 files changed, 119 insertions(+), 32 deletions(-) -- 2.53.0
