Due to a bug in Golang (github.com/golang#27640), the "character device"
bit was omitted when checking file-modes with `os.ModeType`.
This bug was resolved in Go 1.12, but as a result, graphdrivers
would no longer recognize "device" files, causing pulling of
images that have a file with this filemode to fail;
failed to register layer:
unknown file type for /var/lib/docker/vfs/dir/.../dev/console
The current code checked for an exact match of Modes to be set. The
`os.ModeCharDevice` and `os.ModeDevice` bits will always be set in
tandem, however, because the code was only looking for an exact
match, this detection broke now that `os.ModeCharDevice` was added.
This patch changes the code to be more defensive, and instead
check if the `os.ModeDevice` bit is set (either with, or without
the `os.ModeCharDevice` bit).
In addition, some information was added to the error-message if
no type was matched, to assist debugging in case additional types
are added in future.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
commit 617c352e92 "Don't create devices if in a user namespace"
introduced check, which meant to skip mknod operation when run
in user namespace, but instread skipped FIFO and socket files
copy.
Signed-off-by: Maxim Ivanov <ivanov.maxim@gmail.com>
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>
There was a small issue here, where it copied the data using
traditional mechanisms, even when copy_file_range was successful.
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>
