+1 on the revised spec.
It seems like (not this project) someone ought to pursue getting support
for high resolution timestamps into the next NFS specification.
- Garrett
Roger A. Faulkner wrote:
> In response to the e-mail discussion of this case,
> I am submitting this revised specification:
>
> futimens, utimensat
>
> 1. Introduction
>
> This case adds two new functions to the C library,
> futimens() and utimensat(), as follows:
>
> #include <sys/stat.h>
>
> int futimens(int fd, const struct timespec times[2]);
>
> int utimensat(int fd, const char *path,
> const struct timespec times[2], int flag);
>
> In addition, in order to query the timestamp resolution for
> a given file or directory, fpathconf() and pathconf() will
> be extended to accept a new name, _PC_TIMESTAMP_RESOLUTION,
> defined in <unistd.h>. The return value of fpathconf()
> and pathconf() in this case will be a number in the range
> 1 to 1000 million, indicating the number of nanoseconds
> of the file's timestamp resolution. Each local file system
> will be made to understand this new VOP_PATHCONF operation
> and return the appropriate value.
>
> Finally, the touch(1) utility will be updated to use the
> new interfaces and to provide a date_time specification
> that includes up to nanosecond resolution.
>
> The commitment level of these interfaces is Committed.
>
> The release binding is "patch"
> (so it can be back-ported to Solaris 10 if required).
>
> 2. Discussion
>
> Problems with, for example, make on ZFS file systems have
> emerged because ZFS keeps access and modification times for
> its files with nanosecond granularity, while commands such
> as touch(1) will only set access and modification times of
> its target files to microsecond granularity (rounded down).
> See the bugid:
>
> 6539657 touch(1) does not set the nanosecond timestamp
> of a file correctly
>
> The touch(1) command (and possibly others) need a system call
> interface that sets access and modification times of files
> with nanosecond granularity.
>
> Happily, such interfaces have been designed and are specified
> in the latest SUSv4 Posix interface specification:
>
> #include <sys/stat.h>
>
> int futimens(int fd, const struct timespec times[2]);
>
> int utimensat(int fd, const char *path,
> const struct timespec times[2], int flag);
>
> Even though Solaris does not (yet) implement the new Posix
> standard, there is nothing stopping Solaris from providing
> a few of the newly-specified interfaces (provided that the
> names are appropriately hidden from view when an old
> standards-conforming application is compiled).
>
> 3. Interface table
>
> The futimens() and utimensat() functions are Committed.
> Both are specified by the latest Posix specification.
>
> The fpathconf() name _PC_TIMESTAMP_RESOLUTION and operation are
> Committed and are specified by the latest Posix specification.
>
> The updated touch(1) command line interface is Committed
> and is specified by the latest Posix specification.
>
> 4. References
>
> 6815302 Implement futimens, utimensat(POSIX.1-2008) -
> set file modification times with nanosecond granularity
>
> 5. Manual pages.
>
> See the materials directory for the new futimens(2) manual page.
> This is copied from the Posix specification, with minor changes
> such as changing "shall" to "will" in the text.
>
> See the subdirectories 'oldman' and 'newman' under the
> materials directory to view the old and new manual pages for
> getconf.1
> touch.1
> pathconf.2
> utime.2
> utimes.2
> stat.h.3head
> unistd.h.3head
> The 'newman' files contain modifications reflecting the changes
> described in this proposal. Use 'diff' to view the differences
> between the old and new manual pages.
>
> Roger Faulkner
>
>
