On 2024-03-17 09:31:13, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@xxxxxxxxxx>
>
> Before we let fsverity begin writing merkle tree blocks to the file,
> let's perform a minor effort to clean up any stale metadata from a
> previous attempt to enable fsverity. This can only happen if the system
> crashes /and/ the file shrinks, which is unlikely. But we could do a
> better job of cleaning up anyway.
>
> Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
Looks good to me:
Reviewed-by: Andrey Albershteyn <aalbersh@xxxxxxxxxx>
> ---
> fs/xfs/xfs_verity.c | 42 ++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 2 deletions(-)
>
>
> diff --git a/fs/xfs/xfs_verity.c b/fs/xfs/xfs_verity.c
> index c19fa47d1f76..db43e017f10e 100644
> --- a/fs/xfs/xfs_verity.c
> +++ b/fs/xfs/xfs_verity.c
> @@ -413,6 +413,44 @@ xfs_verity_get_descriptor(
> return args.valuelen;
> }
>
> +/*
> + * Clear out old fsverity metadata before we start building a new one. This
> + * could happen if, say, we crashed while building fsverity data.
> + */
> +static int
> +xfs_verity_drop_old_metadata(
> + struct xfs_inode *ip,
> + u64 new_tree_size,
> + unsigned int tree_blocksize)
> +{
> + struct xfs_verity_merkle_key name;
> + struct xfs_da_args args = {
> + .dp = ip,
> + .whichfork = XFS_ATTR_FORK,
> + .attr_filter = XFS_ATTR_VERITY,
> + .op_flags = XFS_DA_OP_REMOVE,
> + .name = (const uint8_t *)&name,
> + .namelen = sizeof(struct xfs_verity_merkle_key),
> + /* NULL value make xfs_attr_set remove the attr */
> + .value = NULL,
> + };
> + u64 offset;
> + int error = 0;
> +
> + /*
> + * Delete as many merkle tree blocks in increasing blkno order until we
> + * don't find any more. That ought to be good enough for avoiding
> + * dead bloat without excessive runtime.
> + */
> + for (offset = new_tree_size; !error; offset += tree_blocksize) {
> + xfs_verity_merkle_key_to_disk(&name, offset);
> + error = xfs_attr_set(&args);
> + }
> + if (error == -ENOATTR)
> + return 0;
> + return error;
> +}
> +
> static int
> xfs_verity_begin_enable(
> struct file *filp,
> @@ -421,7 +459,6 @@ xfs_verity_begin_enable(
> {
> struct inode *inode = file_inode(filp);
> struct xfs_inode *ip = XFS_I(inode);
> - int error = 0;
>
> xfs_assert_ilocked(ip, XFS_IOLOCK_EXCL);
>
> @@ -431,7 +468,8 @@ xfs_verity_begin_enable(
> if (xfs_iflags_test_and_set(ip, XFS_VERITY_CONSTRUCTION))
> return -EBUSY;
>
> - return error;
> + return xfs_verity_drop_old_metadata(ip, merkle_tree_size,
> + tree_blocksize);
> }
>
> static int
>
--
- Andrey
