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| author | Dongliang Cui <dongliang.cui@unisoc.com> | 2024-09-18 00:40:05 +0200 |
|---|---|---|
| committer | Namjae Jeon <linkinjeon@kernel.org> | 2024-09-18 00:40:56 +0200 |
| commit | f761fcdd289d07e8547fef7ac76c3760fc7803f2 (patch) | |
| tree | e6f73e68054e27fb5b925b31c183ebc3fc5abd8f /include/uapi | |
| parent | exfat: do not fallback to buffered write (diff) | |
| download | linux-f761fcdd289d07e8547fef7ac76c3760fc7803f2.tar.xz linux-f761fcdd289d07e8547fef7ac76c3760fc7803f2.zip | |
exfat: Implement sops->shutdown and ioctl
We found that when writing a large file through buffer write, if the
disk is inaccessible, exFAT does not return an error normally, which
leads to the writing process not stopping properly.
To easily reproduce this issue, you can follow the steps below:
1. format a device to exFAT and then mount (with a full disk erase)
2. dd if=/dev/zero of=/exfat_mount/test.img bs=1M count=8192
3. eject the device
You may find that the dd process does not stop immediately and may
continue for a long time.
The root cause of this issue is that during buffer write process,
exFAT does not need to access the disk to look up directory entries
or the FAT table (whereas FAT would do) every time data is written.
Instead, exFAT simply marks the buffer as dirty and returns,
delegating the writeback operation to the writeback process.
If the disk cannot be accessed at this time, the error will only be
returned to the writeback process, and the original process will not
receive the error, so it cannot be returned to the user side.
When the disk cannot be accessed normally, an error should be returned
to stop the writing process.
Implement sops->shutdown and ioctl to shut down the file system
when underlying block device is marked dead.
Signed-off-by: Dongliang Cui <dongliang.cui@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/exfat.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/uapi/linux/exfat.h b/include/uapi/linux/exfat.h new file mode 100644 index 000000000000..46d95b16fc4b --- /dev/null +++ b/include/uapi/linux/exfat.h @@ -0,0 +1,25 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +/* + * Copyright (C) 2024 Unisoc Technologies Co., Ltd. + */ + +#ifndef _UAPI_LINUX_EXFAT_H +#define _UAPI_LINUX_EXFAT_H +#include <linux/types.h> +#include <linux/ioctl.h> + +/* + * exfat-specific ioctl commands + */ + +#define EXFAT_IOC_SHUTDOWN _IOR('X', 125, __u32) + +/* + * Flags used by EXFAT_IOC_SHUTDOWN + */ + +#define EXFAT_GOING_DOWN_DEFAULT 0x0 /* default with full sync */ +#define EXFAT_GOING_DOWN_FULLSYNC 0x1 /* going down with full sync*/ +#define EXFAT_GOING_DOWN_NOSYNC 0x2 /* going down */ + +#endif /* _UAPI_LINUX_EXFAT_H */ |