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Filename Latest commit message Latest commit date
Namjae Jeon 7d8b1148d8 exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree
The call stack shown below is a scenario in the Linux 4.19 kernel.
Allocating memory failed where exfat fs use kmalloc_array due to
system memory fragmentation, while the u-disk was inserted without
recognition.
Devices such as u-disk using the exfat file system are pluggable and
may be insert into the system at any time.
However, long-term running systems cannot guarantee the continuity of
physical memory. Therefore, it's necessary to address this issue.

Binder:2632_6: page allocation failure: order:4,
 mode:0x6040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
Call trace:
[242178.097582]  dump_backtrace+0x0/0x4
[242178.097589]  dump_stack+0xf4/0x134
[242178.097598]  warn_alloc+0xd8/0x144
[242178.097603]  __alloc_pages_nodemask+0x1364/0x1384
[242178.097608]  kmalloc_order+0x2c/0x510
[242178.097612]  kmalloc_order_trace+0x40/0x16c
[242178.097618]  __kmalloc+0x360/0x408
[242178.097624]  load_alloc_bitmap+0x160/0x284
[242178.097628]  exfat_fill_super+0xa3c/0xe7c
[242178.097635]  mount_bdev+0x2e8/0x3a0
[242178.097638]  exfat_fs_mount+0x40/0x50
[242178.097643]  mount_fs+0x138/0x2e8
[242178.097649]  vfs_kern_mount+0x90/0x270
[242178.097655]  do_mount+0x798/0x173c
[242178.097659]  ksys_mount+0x114/0x1ac
[242178.097665]  __arm64_sys_mount+0x24/0x34
[242178.097671]  el0_svc_common+0xb8/0x1b8
[242178.097676]  el0_svc_handler+0x74/0x90
[242178.097681]  el0_svc+0x8/0x340

By analyzing the exfat code,we found that continuous physical memory
is not required here,so kvmalloc_array is used can solve this problem.

Signed-off-by: gaoming <gaoming20@hihonor.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2023-07-12 23:32:11 +09:00
.github/workflows exfat: remove generic/286 2022-12-09 23:20:49 +09:00
balloc.c exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree 2023-07-12 23:32:11 +09:00
cache.c exfat: fix use of uninitialized spinlock on error path 2020-10-12 22:56:52 +09:00
dir.c exfat: handle unreconized benign secondary entries 2023-01-13 22:53:51 +09:00
exfat_fs.h exfat: fs: port ->getattr() to pass mnt_idmap 2023-07-11 22:20:50 +09:00
exfat_raw.h exfat: handle unreconized benign secondary entries 2023-01-13 22:53:51 +09:00
fatent.c exfat: fix the newly allocated clusters are not freed in error handling 2023-07-11 22:20:45 +09:00
file.c exfat: splice: Use filemap_splice_read() instead of generic_file_splice_read() 2023-07-11 22:35:55 +09:00
inode.c exfat: remove ->writepage 2023-07-11 22:20:39 +09:00
Kconfig exfat: fs: build the legacy direct I/O code conditionally 2023-07-11 22:35:47 +09:00
Makefile exfat: fix typo in Makefile 2021-10-14 22:24:23 -07:00
misc.c exfat: Expand exfat_err() and co directly to pr_*() macro 2022-07-29 17:26:04 +09:00
namei.c exfat: fs: port ->rename() to pass mnt_idmap 2023-07-11 22:34:25 +09:00
nls.c exfat: Drop superfluous new line for error messages 2022-07-29 17:26:12 +09:00
README.md exfat: fix typo 2020-02-10 21:35:58 +09:00
super.c exfat: fix inode->i_blocks for non-512 byte sector size device 2023-01-08 18:15:09 +09:00

exFAT filesystem

This is the exfat filesystem for support from the linux 4.1 kernel to the latest kernel.

Installing as a stand-alone module

Install prerequisite package for Fedora, RHEL:

	yum install kernel-devel-$(uname -r)

Build step:

	make
	sudo make install

To load the driver manually, run this as root:

	modprobe exfat

Installing as a part of the kernel

  1. Let's take [linux] as the path to your kernel source dir.
	cd [linux]
	cp -ar exfat [linux]/fs/
  1. edit [linux]/fs/Kconfig
	source "fs/fat/Kconfig"
	+source "fs/exfat/Kconfig"
	source "fs/ntfs/Kconfig"
  1. edit [linux]/fs/Makefile
	obj-$(CONFIG_FAT_FS)          += fat/
	+obj-$(CONFIG_EXFAT_FS)       += exfat/
	obj-$(CONFIG_BFS_FS)          += bfs/
  1. make menuconfig and set exfat
	File systems  --->
		DOS/FAT/NT Filesystems  --->
			<M> exFAT filesystem support
			(utf8) Default iocharset for exFAT

build your kernel