[PATCH 12/16] hostfs: pass 64-bit timestamps to/from user space

Arnd Bergmann
2019-11-08T21:37:02Z

The use of 'struct timespec' is deprecated in the kernel, so we
want to avoid the conversions from/to the proper timespec64
structure.

On the user space side, we have a 'struct timespec' that is defined
by the C library and that will be incompatible with the kernel's
view on 32-bit architectures once they move to a 64-bit time_t,
breaking the shared binary layout of hostfs_iattr and hostfs_stat.

This changes the two structures to use a new hostfs_timespec structure
with fixed 64-bit seconds/nanoseconds for passing the timestamps
between hostfs_kern.c and hostfs_user.c. With a new enough user
space side, this will allow timestamps beyond year 2038.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/hostfs/hostfs.h | 22 +++++++++++++---------
fs/hostfs/hostfs_kern.c | 15 +++++++++------
2 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/fs/hostfs/hostfs.h b/fs/hostfs/hostfs.h
index f4295aa19350..69cb796f6270 100644
--- a/fs/hostfs/hostfs.h
+++ b/fs/hostfs/hostfs.h
@@ -37,16 +37,20 @@
* is on, and remove the appropriate bits from attr->ia_mode (attr is a
* "struct iattr *"). -BlaisorBlade
*/
+struct hostfs_timespec {
+ long long tv_sec;
+ long long tv_nsec;
+};

struct hostfs_iattr {
- unsigned int ia_valid;
- unsigned short ia_mode;
- uid_t ia_uid;
- gid_t ia_gid;
- loff_t ia_size;
- struct timespec ia_atime;
- struct timespec ia_mtime;
- struct timespec ia_ctime;
+ unsigned int ia_valid;
+ unsigned short ia_mode;
+ uid_t ia_uid;
+ gid_t ia_gid;
+ loff_t ia_size;
+ struct hostfs_timespec ia_atime;
+ struct hostfs_timespec ia_mtime;
+ struct hostfs_timespec ia_ctime;
};

struct hostfs_stat {
@@ -56,7 +60,7 @@ struct hostfs_stat {
unsigned int uid;
unsigned int gid;
unsigned long long size;
- struct timespec atime, mtime, ctime;
+ struct hostfs_timespec atime, mtime, ctime;
unsigned int blksize;
unsigned long long blocks;
unsigned int maj;
diff --git a/fs/hostfs/hostfs_kern.c b/fs/hostfs/hostfs_kern.c
index 5a7eb0c79839..e6b8c49076bb 100644
--- a/fs/hostfs/hostfs_kern.c
+++ b/fs/hostfs/hostfs_kern.c
@@ -549,9 +549,9 @@ static int read_name(struct inode *ino, char *name)
set_nlink(ino, st.nlink);
i_uid_write(ino, st.uid);
i_gid_write(ino, st.gid);
- ino->i_atime = timespec_to_timespec64(st.atime);
- ino->i_mtime = timespec_to_timespec64(st.mtime);
- ino->i_ctime = timespec_to_timespec64(st.ctime);
+ ino->i_atime = (struct timespec64){ st.atime.tv_sec, st.atime.tv_nsec };
+ ino->i_mtime = (struct timespec64){ st.mtime.tv_sec, st.mtime.tv_nsec };
+ ino->i_ctime = (struct timespec64){ st.ctime.tv_sec, st.ctime.tv_nsec };
ino->i_size = st.size;
ino->i_blocks = st.blocks;
return 0;
@@ -820,15 +820,18 @@ static int hostfs_setattr(struct dentry *dentry, struct iattr *attr)
}
if (attr->ia_valid & ATTR_ATIME) {
attrs.ia_valid |= HOSTFS_ATTR_ATIME;
- attrs.ia_atime = timespec64_to_timespec(attr->ia_atime);
+ attrs.ia_atime = (struct hostfs_timespec)
+ { attr->ia_atime.tv_sec, attr->ia_atime.tv_nsec };
}
if (attr->ia_valid & ATTR_MTIME) {
attrs.ia_valid |= HOSTFS_ATTR_MTIME;
- attrs.ia_mtime = timespec64_to_timespec(attr->ia_mtime);
+ attrs.ia_mtime = (struct hostfs_timespec)
+ { attr->ia_mtime.tv_sec, attr->ia_mtime.tv_nsec };
}
if (attr->ia_valid & ATTR_CTIME) {
attrs.ia_valid |= HOSTFS_ATTR_CTIME;
- attrs.ia_ctime = timespec64_to_timespec(attr->ia_ctime);
+ attrs.ia_ctime = (struct hostfs_timespec)
+ { attr->ia_ctime.tv_sec, attr->ia_ctime.tv_nsec };
}
if (attr->ia_valid & ATTR_ATIME_SET) {
attrs.ia_valid |= HOSTFS_ATTR_ATIME_SET;
--
2.20.0