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btrfs: fix balance convert to single on 32-bit host CPUs

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Currently, the command:

	btrfs balance start -dconvert=single,soft .

on a Raspberry Pi produces the following kernel message:

	BTRFS error (device mmcblk0p2): balance: invalid convert data profile single

This fails because we use is_power_of_2(unsigned long) to validate
the new data profile, the constant for 'single' profile uses bit 48,
and there are only 32 bits in a long on ARM.

Fix by open-coding the check using u64 variables.

Tested by completing the original balance command on several Raspberry
Pis.

Fixes: 818255feec ("btrfs: use common helper instead of open coding a bit test")
CC: stable@vger.kernel.org # 4.20+
Signed-off-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Zygo Blaxell 2019-09-12 19:55:01 -04:00 committed by David Sterba
parent 4203e96894
commit 7a54789074
1 changed files with 5 additions and 1 deletions
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6
fs/btrfs/volumes.c
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@ -3845,7 +3845,11 @@ static int alloc_profile_is_valid(u64 flags, int extended)
return !extended; /* "0" is valid for usual profiles */
/* true if exactly one bit set */
return is_power_of_2(flags);
/*
* Don't use is_power_of_2(unsigned long) because it won't work
* for the single profile (1ULL << 48) on 32-bit CPUs.
*/
return flags != 0 && (flags & (flags - 1)) == 0;
}
static inline int balance_need_close(struct btrfs_fs_info *fs_info)