Commit 54ebe406 authored Apr 22, 2020 by Anton Ivanov Committed by Richard Weinberger Jun 02, 2020

um: Use fdatasync() when mapping the UBD FSYNC command



We do not need to update the metadata (atime, mtime, etc)
on the UBD file and/or the COW file until UML exits.

UBD image mtime is checked in UML only when opening
the files. After that they are locked and used
exclusively by a single UML instance, so there is
no point wasting resources on updating metadata on
every sync. We can sync data only. The host will
always update mtime if a file has been modified upon
closing it.

Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

parent 0b86ce29

arch/um/os-Linux/file.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -290,7 +290,7 @@ int os_write_file(int fd, const void *buf, int len)

		int os_sync_file(int fd)
		{
		int n = fsync(fd);
		int n = fdatasync(fd);

		if (n < 0)
		return -errno;

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