From c6de84d279542070161e7a12be35bafc80bd3e30 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Fri, 30 Sep 2022 07:18:38 -0400 Subject: [PATCH] vfs: expose STATX_VERSION to userland Claim one of the spare fields in struct statx to hold a 64-bit inode version attribute. When userland requests STATX_VERSION, copy the value from the kstat struct there, and stop masking off STATX_ATTR_VERSION_MONOTONIC. Update the test-statx sample program to output the change attr and MountId. Signed-off-by: Jeff Layton --- fs/stat.c | 12 +++--------- include/linux/stat.h | 9 --------- include/uapi/linux/stat.h | 6 ++++-- samples/vfs/test-statx.c | 8 ++++++-- 4 files changed, 13 insertions(+), 22 deletions(-) diff --git a/fs/stat.c b/fs/stat.c index db03f4c65f01eb..529b7441d0c336 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -605,11 +605,9 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) memset(&tmp, 0, sizeof(tmp)); - /* STATX_VERSION is kernel-only for now */ - tmp.stx_mask = stat->result_mask & ~STATX_VERSION; + tmp.stx_mask = stat->result_mask; tmp.stx_blksize = stat->blksize; - /* STATX_ATTR_VERSION_MONOTONIC is kernel-only for now */ - tmp.stx_attributes = stat->attributes & ~STATX_ATTR_VERSION_MONOTONIC; + tmp.stx_attributes = stat->attributes; tmp.stx_nlink = stat->nlink; tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid); tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid); @@ -633,6 +631,7 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) tmp.stx_mnt_id = stat->mnt_id; tmp.stx_dio_mem_align = stat->dio_mem_align; tmp.stx_dio_offset_align = stat->dio_offset_align; + tmp.stx_version = stat->version; return copy_to_user(buffer, &tmp, sizeof(tmp)) ? -EFAULT : 0; } @@ -648,11 +647,6 @@ int do_statx(int dfd, struct filename *filename, unsigned int flags, if ((flags & AT_STATX_SYNC_TYPE) == AT_STATX_SYNC_TYPE) return -EINVAL; - /* STATX_VERSION is kernel-only for now. Ignore requests - * from userland. - */ - mask &= ~STATX_VERSION; - error = vfs_statx(dfd, filename, flags, &stat, mask); if (error) return error; diff --git a/include/linux/stat.h b/include/linux/stat.h index 4e9428d86a3a82..69c79e4fd1b1d8 100644 --- a/include/linux/stat.h +++ b/include/linux/stat.h @@ -54,13 +54,4 @@ struct kstat { u32 dio_offset_align; u64 version; }; - -/* These definitions are internal to the kernel for now. Mainly used by nfsd. */ - -/* mask values */ -#define STATX_VERSION 0x40000000U /* Want/got stx_change_attr */ - -/* file attribute values */ -#define STATX_ATTR_VERSION_MONOTONIC 0x8000000000000000ULL /* version monotonically increases */ - #endif diff --git a/include/uapi/linux/stat.h b/include/uapi/linux/stat.h index 7cab2c65d3d7fc..4a0a1f27c059f3 100644 --- a/include/uapi/linux/stat.h +++ b/include/uapi/linux/stat.h @@ -127,7 +127,8 @@ struct statx { __u32 stx_dio_mem_align; /* Memory buffer alignment for direct I/O */ __u32 stx_dio_offset_align; /* File offset alignment for direct I/O */ /* 0xa0 */ - __u64 __spare3[12]; /* Spare space for future expansion */ + __u64 stx_version; /* Inode change attribute */ + __u64 __spare3[11]; /* Spare space for future expansion */ /* 0x100 */ }; @@ -154,6 +155,7 @@ struct statx { #define STATX_BTIME 0x00000800U /* Want/got stx_btime */ #define STATX_MNT_ID 0x00001000U /* Got stx_mnt_id */ #define STATX_DIOALIGN 0x00002000U /* Want/got direct I/O alignment info */ +#define STATX_VERSION 0x00004000U /* Want/got stx_version */ #define STATX__RESERVED 0x80000000U /* Reserved for future struct statx expansion */ @@ -189,6 +191,6 @@ struct statx { #define STATX_ATTR_MOUNT_ROOT 0x00002000 /* Root of a mount */ #define STATX_ATTR_VERITY 0x00100000 /* [I] Verity protected file */ #define STATX_ATTR_DAX 0x00200000 /* File is currently in DAX state */ - +#define STATX_ATTR_VERSION_MONOTONIC 0x00400000 /* stx_version increases w/ every change */ #endif /* _UAPI_LINUX_STAT_H */ diff --git a/samples/vfs/test-statx.c b/samples/vfs/test-statx.c index 49c7a46cee0739..bdbc371c977454 100644 --- a/samples/vfs/test-statx.c +++ b/samples/vfs/test-statx.c @@ -107,6 +107,8 @@ static void dump_statx(struct statx *stx) printf("Device: %-15s", buffer); if (stx->stx_mask & STATX_INO) printf(" Inode: %-11llu", (unsigned long long) stx->stx_ino); + if (stx->stx_mask & STATX_MNT_ID) + printf(" MountId: %llx", stx->stx_mnt_id); if (stx->stx_mask & STATX_NLINK) printf(" Links: %-5u", stx->stx_nlink); if (stx->stx_mask & STATX_TYPE) { @@ -145,7 +147,9 @@ static void dump_statx(struct statx *stx) if (stx->stx_mask & STATX_CTIME) print_time("Change: ", &stx->stx_ctime); if (stx->stx_mask & STATX_BTIME) - print_time(" Birth: ", &stx->stx_btime); + print_time("Birth: ", &stx->stx_btime); + if (stx->stx_mask & STATX_VERSION) + printf("Inode Version: 0x%llx\n", stx->stx_version); if (stx->stx_attributes_mask) { unsigned char bits, mbits; @@ -218,7 +222,7 @@ int main(int argc, char **argv) struct statx stx; int ret, raw = 0, atflag = AT_SYMLINK_NOFOLLOW; - unsigned int mask = STATX_BASIC_STATS | STATX_BTIME; + unsigned int mask = STATX_BASIC_STATS | STATX_BTIME | STATX_MNT_ID | STATX_VERSION; for (argv++; *argv; argv++) { if (strcmp(*argv, "-F") == 0) {