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| author | Chris Mason <chris.mason@fusionio.com> | 2013-11-15 12:14:55 +0100 |
|---|---|---|
| committer | Chris Mason <chris.mason@fusionio.com> | 2013-11-15 09:17:47 -0500 |
| commit | 46e0f66a0cf9e1fe25bfdcf4a60c08aface85998 (patch) | |
| tree | 9b454277530b50f41ac5fbbf5f6d0f64ec2ebc99 /fs/btrfs/ioctl.c | |
| parent | 91aef86f3b8ab0685d930a5468254384513d1c97 (diff) | |
| download | linux-46e0f66a0cf9e1fe25bfdcf4a60c08aface85998.tar.gz | |
btrfs: fix empty_zero_page misusage
Heiko Carstens noticed that btrfs was using empty_zero_page
incorrectly. He explained:
The definition of empty_zero_page is architecture specific. It
is (currently) either a character array, an unsigned long
containing the address of the empty_zero_page, or even worse
only the address of the struct page belonging to the
empty_zero_page.
This commit changes btrfs to use a for-loop instead. On x86
the resulting .ko is smaller, and we're no longer worrying about
how each arch builds its zeros.
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/ioctl.c')
| -rw-r--r-- | fs/btrfs/ioctl.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 1d04b5559e61..64a0876c7872 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -368,8 +368,13 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg) int btrfs_is_empty_uuid(u8 *uuid) { - BUILD_BUG_ON(BTRFS_UUID_SIZE > PAGE_SIZE); - return !memcmp(uuid, empty_zero_page, BTRFS_UUID_SIZE); + int i; + + for (i = 0; i < BTRFS_UUID_SIZE; i++) { + if (uuid[i]) + return 0; + } + return 1; } static noinline int create_subvol(struct inode *dir, |