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authorFred Isaman <iisaman@citi.umich.edu>2011-07-30 20:52:48 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-07-31 12:18:16 -0400
commit6d742ba538f98164f3c5e05cdcadb4ec6ddf504f (patch)
treeb87c6f5d42eccfb028a207ce48dfa474c168fd1e /fs/nfs/blocklayout/extents.c
parente9437ccef92a28ba4c9009404bb8c9b5672dc54a (diff)
pnfsblock: bl_find_get_extent
Implement bl_find_get_extent(), one of the core extent manipulation routines. [pnfsblock: Lookup list entry of layouts and tags in reverse order] Signed-off-by: Zhang Jingwang <zhangjingwang@nrchpc.ac.cn> Signed-off-by: Fred Isaman <iisaman@citi.umich.edu> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Jim Rees <rees@umich.edu> pnfsblock: fix print format warnings for sector_t and size_t gcc spews warnings about these on x86_64, e.g.: fs/nfs/blocklayout/blocklayout.c:74: warning: format ‘%Lu’ expects type ‘long long unsigned int’, but argument 2 has type ‘sector_t’ fs/nfs/blocklayout/blocklayout.c:388: warning: format ‘%d’ expects type ‘int’, but argument 5 has type ‘size_t’ Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Benny Halevy <bhalevy@tonian.com> Signed-off-by: Jim Rees <rees@umich.edu> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/blocklayout/extents.c')
-rw-r--r--fs/nfs/blocklayout/extents.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/fs/nfs/blocklayout/extents.c b/fs/nfs/blocklayout/extents.c
index ee4891f3249..8fa93e23cb2 100644
--- a/fs/nfs/blocklayout/extents.c
+++ b/fs/nfs/blocklayout/extents.c
@@ -193,3 +193,50 @@ bl_add_merge_extent(struct pnfs_block_layout *bl,
bl_put_extent(new);
return -EIO;
}
+
+/* Returns extent, or NULL. If a second READ extent exists, it is returned
+ * in cow_read, if given.
+ *
+ * The extents are kept in two seperate ordered lists, one for READ and NONE,
+ * one for READWRITE and INVALID. Within each list, we assume:
+ * 1. Extents are ordered by file offset.
+ * 2. For any given isect, there is at most one extents that matches.
+ */
+struct pnfs_block_extent *
+bl_find_get_extent(struct pnfs_block_layout *bl, sector_t isect,
+ struct pnfs_block_extent **cow_read)
+{
+ struct pnfs_block_extent *be, *cow, *ret;
+ int i;
+
+ dprintk("%s enter with isect %llu\n", __func__, (u64)isect);
+ cow = ret = NULL;
+ spin_lock(&bl->bl_ext_lock);
+ for (i = 0; i < EXTENT_LISTS; i++) {
+ list_for_each_entry_reverse(be, &bl->bl_extents[i], be_node) {
+ if (isect >= be->be_f_offset + be->be_length)
+ break;
+ if (isect >= be->be_f_offset) {
+ /* We have found an extent */
+ dprintk("%s Get %p (%i)\n", __func__, be,
+ atomic_read(&be->be_refcnt.refcount));
+ kref_get(&be->be_refcnt);
+ if (!ret)
+ ret = be;
+ else if (be->be_state != PNFS_BLOCK_READ_DATA)
+ bl_put_extent(be);
+ else
+ cow = be;
+ break;
+ }
+ }
+ if (ret &&
+ (!cow_read || ret->be_state != PNFS_BLOCK_INVALID_DATA))
+ break;
+ }
+ spin_unlock(&bl->bl_ext_lock);
+ if (cow_read)
+ *cow_read = cow;
+ print_bl_extent(ret);
+ return ret;
+}