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>

1 files changed, 30 insertions, 0 deletions

diff --git a/fs/nfs/blocklayout/blocklayout.c b/fs/nfs/blocklayout/blocklayout.c
index 8502e620f644..d3c3c5c972c3 100644
--- a/fs/nfs/blocklayout/blocklayout.c
+++ b/fs/nfs/blocklayout/blocklayout.c
@@ -470,6 +470,35 @@ static struct pnfs_layout_segment *bl_alloc_lseg(struct pnfs_layout_hdr *lo,
 }
 
 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,