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author | Filipe Manana <fdmanana@suse.com> | 2016-01-06 22:42:35 +0000 |
---|---|---|
committer | Filipe Manana <fdmanana@suse.com> | 2016-01-07 21:16:03 +0000 |
commit | 8cdc7c5b00d945a3c823fc4277af304abb9cb43d (patch) | |
tree | b5e0728e93d7cdd756cc942b2671593266d16fa8 /fs | |
parent | 271dba4521aed0c37c063548f876b49f5cd64b2e (diff) | |
download | op-kernel-dev-8cdc7c5b00d945a3c823fc4277af304abb9cb43d.zip op-kernel-dev-8cdc7c5b00d945a3c823fc4277af304abb9cb43d.tar.gz |
Btrfs: fix fitrim discarding device area reserved for boot loader's use
As of the 4.3 kernel release, the fitrim ioctl can now discard any region
of a disk that is not allocated to any chunk/block group, including the
first megabyte which is used for our primary superblock and by the boot
loader (grub for example).
Fix this by not allowing to trim/discard any region in the device starting
with an offset not greater than min(alloc_start_mount_option, 1Mb), just
as it was not possible before 4.3.
A reproducer test case for xfstests follows.
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
cd /
rm -f $tmp.*
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
# real QA test starts here
_need_to_be_root
_supported_fs btrfs
_supported_os Linux
_require_scratch
rm -f $seqres.full
_scratch_mkfs >>$seqres.full 2>&1
# Write to the [0, 64Kb[ and [68Kb, 1Mb[ ranges of the device. These ranges are
# reserved for a boot loader to use (GRUB for example) and btrfs should never
# use them - neither for allocating metadata/data nor should trim/discard them.
# The range [64Kb, 68Kb[ is used for the primary superblock of the filesystem.
$XFS_IO_PROG -c "pwrite -S 0xfd 0 64K" $SCRATCH_DEV | _filter_xfs_io
$XFS_IO_PROG -c "pwrite -S 0xfd 68K 956K" $SCRATCH_DEV | _filter_xfs_io
# Now mount the filesystem and perform a fitrim against it.
_scratch_mount
_require_batched_discard $SCRATCH_MNT
$FSTRIM_PROG $SCRATCH_MNT
# Now unmount the filesystem and verify the content of the ranges was not
# modified (no trim/discard happened on them).
_scratch_unmount
echo "Content of the ranges [0, 64Kb] and [68Kb, 1Mb[ after fitrim:"
od -t x1 -N $((64 * 1024)) $SCRATCH_DEV
od -t x1 -j $((68 * 1024)) -N $((956 * 1024)) $SCRATCH_DEV
status=0
exit
Reported-by: Vincent Petry <PVince81@yahoo.fr>
Reported-by: Andrei Borzenkov <arvidjaar@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109341
Fixes: 499f377f49f0 (btrfs: iterate over unused chunk space in FITRIM)
Cc: stable@vger.kernel.org # 4.3+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/btrfs/volumes.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index a114b7b..b0a0eb2 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -1258,6 +1258,15 @@ int find_free_dev_extent_start(struct btrfs_transaction *transaction, int ret; int slot; struct extent_buffer *l; + u64 min_search_start; + + /* + * We don't want to overwrite the superblock on the drive nor any area + * used by the boot loader (grub for example), so we make sure to start + * at an offset of at least 1MB. + */ + min_search_start = max(root->fs_info->alloc_start, 1024ull * 1024); + search_start = max(search_start, min_search_start); path = btrfs_alloc_path(); if (!path) @@ -1398,18 +1407,9 @@ int find_free_dev_extent(struct btrfs_trans_handle *trans, struct btrfs_device *device, u64 num_bytes, u64 *start, u64 *len) { - struct btrfs_root *root = device->dev_root; - u64 search_start; - /* FIXME use last free of some kind */ - - /* - * we don't want to overwrite the superblock on the drive, - * so we make sure to start at an offset of at least 1MB - */ - search_start = max(root->fs_info->alloc_start, 1024ull * 1024); return find_free_dev_extent_start(trans->transaction, device, - num_bytes, search_start, start, len); + num_bytes, 0, start, len); } static int btrfs_free_dev_extent(struct btrfs_trans_handle *trans, |