> On Aug 22, 2016, at 09:48, Benjamin Coddington <bcodding@xxxxxxxxxx> wrote:
>
> Change from v1:
>
> Instead of moving the i_lock protected region around, store last written
> byte for block layouts on struct pnfs_block_layout and use that when
> encoding LAYOUTCOMMIT.
>
> 8<------------------------------------------------------------------------
>
> Block/SCSI layout write completion may add committable extents to the
> extent tree before updating the layout's last-written byte under the inode
> lock. If a sync happens before this value is updated, then
> prepare_layoutcommit may find and encode these extents which would produce
> a LAYOUTCOMMIT request whose encoded extents are larger than the request's
> loca_length.
>
> Fix this by using a last-written byte value that is updated atomically with
> the extent tree.
>
> Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx>
> ---
> fs/nfs/blocklayout/blocklayout.c | 2 +-
> fs/nfs/blocklayout/blocklayout.h | 3 ++-
> fs/nfs/blocklayout/extent_tree.c | 8 +++++---
> 3 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
> index 17a42e4eb872..25cdd559831c 100644
> --- a/fs/nfs/blocklayout/blocklayout.c
> +++ b/fs/nfs/blocklayout/blocklayout.c
> @@ -344,7 +344,7 @@ static void bl_write_cleanup(struct work_struct *work)
> PAGE_SIZE - 1) & (loff_t)PAGE_MASK;
>
> ext_tree_mark_written(bl, start >> SECTOR_SHIFT,
> - (end - start) >> SECTOR_SHIFT);
> + (end - start) >> SECTOR_SHIFT, end);
> }
>
> pnfs_ld_write_done(hdr);
> diff --git a/fs/nfs/blocklayout/blocklayout.h b/fs/nfs/blocklayout/blocklayout.h
> index 18e6fd0b9506..efc007f00742 100644
> --- a/fs/nfs/blocklayout/blocklayout.h
> +++ b/fs/nfs/blocklayout/blocklayout.h
> @@ -141,6 +141,7 @@ struct pnfs_block_layout {
> struct rb_root bl_ext_ro;
> spinlock_t bl_ext_lock; /* Protects list manipulation */
> bool bl_scsi_layout;
> + u64 bl_lwb;
> };
>
> static inline struct pnfs_block_layout *
> @@ -182,7 +183,7 @@ int ext_tree_insert(struct pnfs_block_layout *bl,
> int ext_tree_remove(struct pnfs_block_layout *bl, bool rw, sector_t start,
> sector_t end);
> int ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,
> - sector_t len);
> + sector_t len, u64 lwb);
> bool ext_tree_lookup(struct pnfs_block_layout *bl, sector_t isect,
> struct pnfs_block_extent *ret, bool rw);
> int ext_tree_prepare_commit(struct nfs4_layoutcommit_args *arg);
> diff --git a/fs/nfs/blocklayout/extent_tree.c b/fs/nfs/blocklayout/extent_tree.c
> index 992bcb19c11e..8d08dfe1e057 100644
> --- a/fs/nfs/blocklayout/extent_tree.c
> +++ b/fs/nfs/blocklayout/extent_tree.c
> @@ -402,7 +402,7 @@ ext_tree_split(struct rb_root *root, struct pnfs_block_extent *be,
>
> int
> ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,
> - sector_t len)
> + sector_t len, u64 lwb)
> {
> struct rb_root *root = &bl->bl_ext_rw;
> sector_t end = start + len;
> @@ -471,6 +471,7 @@ ext_tree_mark_written(struct pnfs_block_layout *bl, sector_t start,
> }
> }
> out:
> + bl->bl_lwb = lwb;
> spin_unlock(&bl->bl_ext_lock);
>
> __ext_put_deviceids(&tmp);
> @@ -518,7 +519,7 @@ static __be32 *encode_scsi_range(struct pnfs_block_extent *be, __be32 *p)
> }
>
> static int ext_tree_encode_commit(struct pnfs_block_layout *bl, __be32 *p,
> - size_t buffer_size, size_t *count)
> + size_t buffer_size, size_t *count, __u64 *lastbyte)
> {
> struct pnfs_block_extent *be;
> int ret = 0;
> @@ -541,6 +542,7 @@ static int ext_tree_encode_commit(struct pnfs_block_layout *bl, __be32 *p,
> else
> p = encode_block_extent(be, p);
> be->be_tag = EXTENT_COMMITTING;
> + *lastbyte = bl->bl_lwb - 1;
> }
> spin_unlock(&bl->bl_ext_lock);
>
> @@ -564,7 +566,7 @@ ext_tree_prepare_commit(struct nfs4_layoutcommit_args *arg)
> arg->layoutupdate_pages = &arg->layoutupdate_page;
>
> retry:
> - ret = ext_tree_encode_commit(bl, start_p + 1, buffer_size, &count);
> + ret = ext_tree_encode_commit(bl, start_p + 1, buffer_size, &count, &arg->lastbytewritten);
> if (unlikely(ret)) {
> ext_tree_free_commitdata(arg, buffer_size);
>
That looks good. Thanks!
Trond
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
