On Sunday 18 October 2020 3:20:11 AM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> In commit fe341eb151ec, I forgot that xfs_free_file_space isn't strictly
> a "remove mapped blocks" function. It is actually a function to zero
> file space by punching out the middle and writing zeroes to the
> unaligned ends of the specified range. Therefore, putting a rtextsize
> alignment check in that function is wrong because that breaks unaligned
> ZERO_RANGE on the realtime volume.
>
> Furthermore, xfs_file_fallocate already has alignment checks for the
> functions require the file range to be aligned to the size of a
> fundamental allocation unit (which is 1 FSB on the data volume and 1 rt
> extent on the realtime volume). Create a new helper to check fallocate
> arguments against the realtiem allocation unit size, fix the fallocate
> frontend to use it, fix free_file_space to delete the correct range, and
> remove a now redundant check from insert_file_space.
>
> NOTE: The realtime extent size is not required to be a power of two!
>
Looks good to me.
Reviewed-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
> Fixes: fe341eb151ec ("xfs: ensure that fpunch, fcollapse, and finsert operations are aligned to rt extent size")
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
> v2: fix this to actually handle rtextsize not being a power of 2, add
> testcase
> ---
> fs/xfs/xfs_bmap_util.c | 17 ++++-------------
> fs/xfs/xfs_file.c | 40 +++++++++++++++++++++++++++++++++++-----
> 2 files changed, 39 insertions(+), 18 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
> index f2a8a0e75e1f..52cddcfee8a1 100644
> --- a/fs/xfs/xfs_bmap_util.c
> +++ b/fs/xfs/xfs_bmap_util.c
> @@ -947,11 +947,10 @@ xfs_free_file_space(
> endoffset_fsb = XFS_B_TO_FSBT(mp, offset + len);
>
> /* We can only free complete realtime extents. */
> - if (XFS_IS_REALTIME_INODE(ip)) {
> - xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
> -
> - if ((startoffset_fsb | endoffset_fsb) & (extsz - 1))
> - return -EINVAL;
> + if (XFS_IS_REALTIME_INODE(ip) && mp->m_sb.sb_rextsize > 0) {
> + startoffset_fsb = round_up(startoffset_fsb,
> + mp->m_sb.sb_rextsize);
> + endoffset_fsb = round_down(endoffset_fsb, mp->m_sb.sb_rextsize);
> }
>
> /*
> @@ -1147,14 +1146,6 @@ xfs_insert_file_space(
>
> trace_xfs_insert_file_space(ip);
>
> - /* We can only insert complete realtime extents. */
> - if (XFS_IS_REALTIME_INODE(ip)) {
> - xfs_extlen_t extsz = xfs_get_extsz_hint(ip);
> -
> - if ((stop_fsb | shift_fsb) & (extsz - 1))
> - return -EINVAL;
> - }
> -
> error = xfs_bmap_can_insert_extents(ip, stop_fsb, shift_fsb);
> if (error)
> return error;
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 3d1b95124744..9e97815887c5 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -785,6 +785,39 @@ xfs_break_layouts(
> return error;
> }
>
> +/*
> + * Decide if the given file range is aligned to the size of the fundamental
> + * allocation unit for the file.
> + */
> +static bool
> +xfs_is_falloc_aligned(
> + struct xfs_inode *ip,
> + loff_t pos,
> + long long int len)
> +{
> + struct xfs_mount *mp = ip->i_mount;
> + uint64_t mask;
> +
> + if (XFS_IS_REALTIME_INODE(ip)) {
> + if (!is_power_of_2(mp->m_sb.sb_rextsize)) {
> + u64 rextbytes;
> + u32 mod;
> +
> + rextbytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
> + div_u64_rem(pos, rextbytes, &mod);
> + if (mod)
> + return false;
> + div_u64_rem(len, rextbytes, &mod);
> + return mod == 0;
> + }
> + mask = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize) - 1;
> + } else {
> + mask = mp->m_sb.sb_blocksize - 1;
> + }
> +
> + return !((pos | len) & mask);
> +}
> +
> #define XFS_FALLOC_FL_SUPPORTED \
> (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
> FALLOC_FL_COLLAPSE_RANGE | FALLOC_FL_ZERO_RANGE | \
> @@ -850,9 +883,7 @@ xfs_file_fallocate(
> if (error)
> goto out_unlock;
> } else if (mode & FALLOC_FL_COLLAPSE_RANGE) {
> - unsigned int blksize_mask = i_blocksize(inode) - 1;
> -
> - if (offset & blksize_mask || len & blksize_mask) {
> + if (!xfs_is_falloc_aligned(ip, offset, len)) {
> error = -EINVAL;
> goto out_unlock;
> }
> @@ -872,10 +903,9 @@ xfs_file_fallocate(
> if (error)
> goto out_unlock;
> } else if (mode & FALLOC_FL_INSERT_RANGE) {
> - unsigned int blksize_mask = i_blocksize(inode) - 1;
> loff_t isize = i_size_read(inode);
>
> - if (offset & blksize_mask || len & blksize_mask) {
> + if (!xfs_is_falloc_aligned(ip, offset, len)) {
> error = -EINVAL;
> goto out_unlock;
> }
>
--
chandan
