`rename_file' was exported but not properly namespaced causing a
multiple definition error because `rename_file' is already defined in
fs/hostfs/hostfs_user.c:

ld: drivers/staging/exfat/exfat_core.o: in function `rename_file':
drivers/staging/exfat/exfat_core.c:2327: multiple definition of
`rename_file'; fs/hostfs/hostfs_user.o:fs/hostfs/hostfs_user.c:350:
first defined here
make: *** [Makefile:1077: vmlinux] Error 1

This error can be reproduced on ARCH=um by selecting:

CONFIG_EXFAT_FS=y
CONFIG_HOSTFS=y

Add a namespace prefix exfat_* to fix this error.

Reported-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Brendan Higgins <brendanhiggins@google.com>
Cc: stable <stable@vger.kernel.org>
Cc: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Tested-by: David Gow <davidgow@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20191204234522.42855-1-brendanhiggins@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently the discard code in clr_alloc_bitmap() is just dead code.
Move code around so that the discard operation is properly attempted
when enabled.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Link: https://lore.kernel.org/r/20191205152913.GJ3276@xps-13
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a spelling mistake in a kernel info message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20191114221509.10728-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix sparse warnings:

drivers/staging/exfat/exfat_core.c:2045:4: warning: symbol 'calc_checksum_1byte' was not declared. Should it be static?
drivers/staging/exfat/exfat_core.c:2080:5: warning: symbol 'calc_checksum_4byte' was not declared. Should it be static?

The two functions has no caller in tree, so remove it.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Link: https://lore.kernel.org/r/20191114140348.46088-1-yuehaibing@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a declaration that requires indentation. Add in
the missing tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20191113164210.103586-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Updating with the current laundry list of things that need attention.

Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112223609.163501-1-Valdis.Kletnieks@vt.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename all the FAT_* functions to exfat_fat_*.

Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112211238.156490-13-Valdis.Kletnieks@vt.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Global functions called 'buf*' are a linkage editor disaster waiting to
happen.  Rename our buf_* functions to exfat_buf_*

Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112211238.156490-12-Valdis.Kletnieks@vt.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move a few more things so we can make them static and clear exfat.h out.
At this point, pretty much everything that can be static is static.
(Note: FAT_sync(), buf_sync(), and sync_alloc_bitmap() aren't called
anyplace, but aren't static because (a) that will toss an error and
(b) they probably *should* be getting called someplace

Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112211238.156490-11-Valdis.Kletnieks@vt.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Some more functions that can be moved and made static

Signed-off-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Link: https://lore.kernel.org/r/20191112211238.156490-10-Valdis.Kletnieks@vt.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>