On Wed, May 04, 2022 at 08:17:21AM +1000, Dave Chinner wrote:
> From: Dave Chinner <dchinner@xxxxxxxxxx>
>
> Callers currently have to round out the size of buffers to match the
> aligment constraints of log iovecs and xlog_write(). They should not
> need to know this detail, so introduce a new function to calculate
> the iovec length (for use in ->iop_size implementations). Also
> modify xlog_finish_iovec() to round up the length to the correct
> alignment so the callers don't need to do this, either.
>
> Convert the only user - inode forks - of this alignment rounding to
> use the new interface.
>
> Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
> ---
> fs/xfs/libxfs/xfs_inode_fork.c | 20 ++++------------
> fs/xfs/xfs_inode_item.c | 25 ++++++--------------
> fs/xfs/xfs_inode_item_recover.c | 4 ++--
> fs/xfs/xfs_log.h | 42 ++++++++++++++++++++++++++++++---
> 4 files changed, 52 insertions(+), 39 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
> index a15ff38c3d41..1a4cdf550f6d 100644
> --- a/fs/xfs/libxfs/xfs_inode_fork.c
> +++ b/fs/xfs/libxfs/xfs_inode_fork.c
> @@ -36,7 +36,7 @@ xfs_init_local_fork(
> int64_t size)
> {
> struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
> - int mem_size = size, real_size = 0;
> + int mem_size = size;
> bool zero_terminate;
>
> /*
> @@ -50,13 +50,7 @@ xfs_init_local_fork(
> mem_size++;
>
> if (size) {
> - /*
> - * As we round up the allocation here, we need to ensure the
> - * bytes we don't copy data into are zeroed because the log
> - * vectors still copy them into the journal.
> - */
> - real_size = roundup(mem_size, 4);
> - ifp->if_u1.if_data = kmem_zalloc(real_size, KM_NOFS);
> + ifp->if_u1.if_data = kmem_alloc(mem_size, KM_NOFS);
> memcpy(ifp->if_u1.if_data, data, size);
> if (zero_terminate)
> ifp->if_u1.if_data[size] = '\0';
> @@ -502,14 +496,8 @@ xfs_idata_realloc(
> return;
> }
>
> - /*
> - * For inline data, the underlying buffer must be a multiple of 4 bytes
> - * in size so that it can be logged and stay on word boundaries.
> - * We enforce that here, and use __GFP_ZERO to ensure that size
> - * extensions always zero the unused roundup area.
> - */
> - ifp->if_u1.if_data = krealloc(ifp->if_u1.if_data, roundup(new_size, 4),
> - GFP_NOFS | __GFP_NOFAIL | __GFP_ZERO);
> + ifp->if_u1.if_data = krealloc(ifp->if_u1.if_data, new_size,
> + GFP_NOFS | __GFP_NOFAIL);
> ifp->if_bytes = new_size;
> }
>
> diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
> index 00733a18ccdc..721def0639fd 100644
> --- a/fs/xfs/xfs_inode_item.c
> +++ b/fs/xfs/xfs_inode_item.c
> @@ -71,7 +71,7 @@ xfs_inode_item_data_fork_size(
> case XFS_DINODE_FMT_LOCAL:
> if ((iip->ili_fields & XFS_ILOG_DDATA) &&
> ip->i_df.if_bytes > 0) {
> - *nbytes += roundup(ip->i_df.if_bytes, 4);
> + *nbytes += xlog_calc_iovec_len(ip->i_df.if_bytes);
> *nvecs += 1;
> }
> break;
> @@ -112,7 +112,7 @@ xfs_inode_item_attr_fork_size(
> case XFS_DINODE_FMT_LOCAL:
> if ((iip->ili_fields & XFS_ILOG_ADATA) &&
> ip->i_afp->if_bytes > 0) {
> - *nbytes += roundup(ip->i_afp->if_bytes, 4);
> + *nbytes += xlog_calc_iovec_len(ip->i_afp->if_bytes);
> *nvecs += 1;
> }
> break;
> @@ -204,17 +204,12 @@ xfs_inode_item_format_data_fork(
> ~(XFS_ILOG_DEXT | XFS_ILOG_DBROOT | XFS_ILOG_DEV);
> if ((iip->ili_fields & XFS_ILOG_DDATA) &&
> ip->i_df.if_bytes > 0) {
> - /*
> - * Round i_bytes up to a word boundary.
> - * The underlying memory is guaranteed
> - * to be there by xfs_idata_realloc().
> - */
> - data_bytes = roundup(ip->i_df.if_bytes, 4);
> ASSERT(ip->i_df.if_u1.if_data != NULL);
> ASSERT(ip->i_disk_size > 0);
> xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_ILOCAL,
> - ip->i_df.if_u1.if_data, data_bytes);
> - ilf->ilf_dsize = (unsigned)data_bytes;
> + ip->i_df.if_u1.if_data,
> + ip->i_df.if_bytes);
> + ilf->ilf_dsize = (unsigned)ip->i_df.if_bytes;
> ilf->ilf_size++;
> } else {
> iip->ili_fields &= ~XFS_ILOG_DDATA;
> @@ -288,17 +283,11 @@ xfs_inode_item_format_attr_fork(
>
> if ((iip->ili_fields & XFS_ILOG_ADATA) &&
> ip->i_afp->if_bytes > 0) {
> - /*
> - * Round i_bytes up to a word boundary.
> - * The underlying memory is guaranteed
> - * to be there by xfs_idata_realloc().
> - */
> - data_bytes = roundup(ip->i_afp->if_bytes, 4);
> ASSERT(ip->i_afp->if_u1.if_data != NULL);
> xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_IATTR_LOCAL,
> ip->i_afp->if_u1.if_data,
> - data_bytes);
> - ilf->ilf_asize = (unsigned)data_bytes;
> + ip->i_afp->if_bytes);
> + ilf->ilf_asize = (unsigned)ip->i_afp->if_bytes;
> ilf->ilf_size++;
> } else {
> iip->ili_fields &= ~XFS_ILOG_ADATA;
> diff --git a/fs/xfs/xfs_inode_item_recover.c b/fs/xfs/xfs_inode_item_recover.c
> index 6d44f5fd6d7e..d28ffaebd067 100644
> --- a/fs/xfs/xfs_inode_item_recover.c
> +++ b/fs/xfs/xfs_inode_item_recover.c
> @@ -462,7 +462,7 @@ xlog_recover_inode_commit_pass2(
> ASSERT(in_f->ilf_size <= 4);
> ASSERT((in_f->ilf_size == 3) || (fields & XFS_ILOG_AFORK));
> ASSERT(!(fields & XFS_ILOG_DFORK) ||
> - (len == in_f->ilf_dsize));
> + (len == xlog_calc_iovec_len(in_f->ilf_dsize)));
>
> switch (fields & XFS_ILOG_DFORK) {
> case XFS_ILOG_DDATA:
> @@ -497,7 +497,7 @@ xlog_recover_inode_commit_pass2(
> }
> len = item->ri_buf[attr_index].i_len;
> src = item->ri_buf[attr_index].i_addr;
> - ASSERT(len == in_f->ilf_asize);
> + ASSERT(len == xlog_calc_iovec_len(in_f->ilf_asize));
>
> switch (in_f->ilf_fields & XFS_ILOG_AFORK) {
> case XFS_ILOG_ADATA:
> diff --git a/fs/xfs/xfs_log.h b/fs/xfs/xfs_log.h
> index 8dafe8f771c7..3a4f6a4e4eb7 100644
> --- a/fs/xfs/xfs_log.h
> +++ b/fs/xfs/xfs_log.h
> @@ -21,23 +21,59 @@ struct xfs_log_vec {
>
> #define XFS_LOG_VEC_ORDERED (-1)
>
> +/*
> + * Calculate the log iovec length for a given user buffer length. Intended to be
> + * used by ->iop_size implementations when sizing buffers of arbitrary
> + * alignments.
> + */
> +static inline int
> +xlog_calc_iovec_len(int len)
> +{
> + return roundup(len, sizeof(uint32_t));
> +}
> +
> void *xlog_prepare_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp,
> uint type);
>
> static inline void
> -xlog_finish_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec *vec, int len)
> +xlog_finish_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec *vec,
> + int data_len)
> {
> struct xlog_op_header *oph = vec->i_addr;
> -
> - /* opheader tracks payload length, logvec tracks region length */
> + int len;
> +
> + /*
> + * Always round up the length to the correct alignment so callers don't
> + * need to know anything about this log vec layout requirement. This
> + * means we have to zero the area the data to be written does not cover.
> + * This is complicated by fact the payload region is offset into the
> + * logvec region by the opheader that tracks the payload.
> + */
> + len = xlog_calc_iovec_len(data_len);
> + if (len - data_len != 0) {
> + char *buf = vec->i_addr + sizeof(struct xlog_op_header);
> +
> + memset(buf + data_len, 0, len - data_len);
Assuming this is the replacement for the kzalloc/kzrealloc calls above
so that we don't write junk to disk,
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> + }
> +
> + /*
> + * The opheader tracks aligned payload length, whilst the logvec tracks
> + * the overall region length.
> + */
> oph->oh_len = cpu_to_be32(len);
>
> len += sizeof(struct xlog_op_header);
> lv->lv_buf_len += len;
> lv->lv_bytes += len;
> vec->i_len = len;
> +
> + /* Catch buffer overruns */
> + ASSERT((void *)lv->lv_buf + lv->lv_bytes <= (void *)lv + lv->lv_size);
> }
>
> +/*
> + * Copy the amount of data requested by the caller into a new log iovec.
> + */
> static inline void *
> xlog_copy_iovec(struct xfs_log_vec *lv, struct xfs_log_iovec **vecp,
> uint type, void *data, int len)
> --
> 2.35.1
>
