comparison mercurial/util.py @ 31575:e506e461c7a9

util: disable hardlink for copyfile if fstype is outside a whitelist

Since osutil.getfstype is available, use it to detect filesystem types. The
whitelist currently includes common local filesystems on Linux where they
should have good hardlink support. We may add new filesystems for other
platforms later.

31574:a8e55d6f1d67

# Hardlinks are problematic on CIFS, do not allow hardlinks
# until we find a way to work around it cleanly (issue4546).
# This is a variable so extensions can opt-in to using them.
allowhardlinks = False

def copyfile(src, dest, hardlink=False, copystat=False, checkambig=False):
    '''copy a file, preserving mode and optionally other stat info like
    atime/mtime

    checkambig argument is used with filestat, and is useful only if

    oldstat = None
    if os.path.lexists(dest):
        if checkambig:
            oldstat = checkambig and filestat(dest)
        unlink(dest)
    if allowhardlinks and hardlink:
        try:
            oslink(src, dest)
            return
        except (IOError, OSError):

31575:e506e461c7a9

# Hardlinks are problematic on CIFS, do not allow hardlinks
# until we find a way to work around it cleanly (issue4546).
# This is a variable so extensions can opt-in to using them.
allowhardlinks = False

# a whilelist of known filesystems where hardlink works reliably
_hardlinkfswhitelist = set([
    'btrfs',
    'ext2',
    'ext3',
    'ext4',
    'jfs',
    'reiserfs',
    'tmpfs',
    'xfs',
])

def copyfile(src, dest, hardlink=False, copystat=False, checkambig=False):
    '''copy a file, preserving mode and optionally other stat info like
    atime/mtime

    checkambig argument is used with filestat, and is useful only if

    oldstat = None
    if os.path.lexists(dest):
        if checkambig:
            oldstat = checkambig and filestat(dest)
        unlink(dest)
    if hardlink:
        # Hardlinks are problematic on CIFS (issue4546), do not allow hardlinks
        # unless we are confident that dest is on a whitelisted filesystem.
        destdir = os.path.dirname(dest)
        fstype = getattr(osutil, 'getfstype', lambda x: None)(destdir)
        if fstype not in _hardlinkfswhitelist:
            hardlink = False
    if allowhardlinks and hardlink:
        try:
            oslink(src, dest)
            return
        except (IOError, OSError):