pnfs/blocklayout: implement the return_range method

This allows removing extents from the extent tree especially on truncate
operations, and thus fixing reads from truncated and re-extended that
previously returned stale data.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 8502e620f64422b7c7b8d23ac86969fe521f4bc3..d3c3c5c972c31c4a288ba963fc33bbc481e968f4 100644 (file)
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -469,6 +469,35 @@ static struct pnfs_layout_segment *bl_alloc_lseg(struct pnfs_layout_hdr *lo,
        return lseg;
 }
 
+static void
+bl_return_range(struct pnfs_layout_hdr *lo,
+               struct pnfs_layout_range *range)
+{
+       struct pnfs_block_layout *bl = BLK_LO2EXT(lo);
+       sector_t offset = range->offset >> SECTOR_SHIFT, end;
+       int err;
+
+       if (range->offset % 8) {
+               dprintk("%s: offset %lld not block size aligned\n",
+                       __func__, range->offset);
+               return;
+       }
+
+       if (range->length != NFS4_MAX_UINT64) {
+               if (range->length % 8) {
+                       dprintk("%s: length %lld not block size aligned\n",
+                               __func__, range->length);
+                       return;
+               }
+
+               end = offset + (range->length >> SECTOR_SHIFT);
+       } else {
+               end = round_down(NFS4_MAX_UINT64, PAGE_SIZE);
+       }
+
+       err = ext_tree_remove(bl, range->iomode & IOMODE_RW, offset, end);
+}
+
 static void
 bl_encode_layoutcommit(struct pnfs_layout_hdr *lo, struct xdr_stream *xdr,
                       const struct nfs4_layoutcommit_args *arg)
@@ -777,6 +806,7 @@ static struct pnfs_layoutdriver_type blocklayout_type = {
        .free_layout_hdr                = bl_free_layout_hdr,
        .alloc_lseg                     = bl_alloc_lseg,
        .free_lseg                      = bl_free_lseg,
+       .return_range                   = bl_return_range,
        .encode_layoutcommit            = bl_encode_layoutcommit,
        .cleanup_layoutcommit           = bl_cleanup_layoutcommit,
        .set_layoutdriver               = bl_set_layoutdriver,