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authorFilipe Manana <fdmanana@suse.com>2016-01-06 23:42:35 +0100
committerFilipe Manana <fdmanana@suse.com>2016-01-07 22:16:03 +0100
commit8cdc7c5b00d945a3c823fc4277af304abb9cb43d (patch)
treeb5e0728e93d7cdd756cc942b2671593266d16fa8 /fs
parentBtrfs: fix transaction handle leak on failure to create hard link (diff)
downloadlinux-8cdc7c5b00d945a3c823fc4277af304abb9cb43d.tar.xz
linux-8cdc7c5b00d945a3c823fc4277af304abb9cb43d.zip
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.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index a114b7bb87a0..b0a0eb242473 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,