Previously, the code would set the mtime on the directories before
creating files in the directory itself. This was problematic
because it resulted in the mtimes on the directories being
incorrectly set. This change makes it so that the mtime is
set only _after_ all of the files have been created.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
This change makes the VFS graphdriver use the kernel-accelerated
(copy_file_range) mechanism of copying files, which is able to
leverage reflinks.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
Previously, graphdriver/copy would improperly copy hardlinks as just regular
files. This patch changes that behaviour, and instead the code now keeps
track of inode numbers, and if it sees the same inode number again
during the copy loop, it hardlinks it, instead of copying it.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
This changeset allows Docker's VFS, and Overlay to take advantage of
Linux's zerocopy APIs.
The copy function first tries to use the ficlone ioctl. Reason being:
- they do not allow partial success (aka short writes)
- clones are expected to be a fast metadata operation
See: http://oss.sgi.com/archives/xfs/2015-12/msg00356.html
If the clone fails, we fall back to copy_file_range, which internally
may fall back to splice, which has an upper limit on the size
of copy it can perform. Given that, we have to loop until the copy
is done.
For a given dirCopy operation, if the clone fails, we will not try
it again during any other file copy. Same is true with copy_file_range.
If all else fails, we fall back to traditional copy.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
