nilfs2: support contiguous lookup of blocks

Although get_block() callback function can return extent of contiguous
blocks with bh->b_size, nilfs_get_block() function did not support
this feature.

This adds contiguous lookup feature to the block mapping codes of
nilfs, and allows the nilfs_get_blocks() function to return the extent
information by applying the feature.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

1 files changed, 43 insertions, 0 deletions

diff --git a/fs/nilfs2/direct.c b/fs/nilfs2/direct.c
index 33467adf094b..342d9765df8d 100644
--- a/fs/nilfs2/direct.c
+++ b/fs/nilfs2/direct.c
@@ -25,6 +25,7 @@
 #include "page.h"
 #include "direct.h"
 #include "alloc.h"
+#include "dat.h"
 
 static inline __le64 *nilfs_direct_dptrs(const struct nilfs_direct *direct)
 {
@@ -62,6 +63,47 @@ static int nilfs_direct_lookup(const struct nilfs_bmap *bmap,
         return 0;
 }
 
+static int nilfs_direct_lookup_contig(const struct nilfs_bmap *bmap,
+                                      __u64 key, __u64 *ptrp,
+                                      unsigned maxblocks)
+{
+        struct nilfs_direct *direct = (struct nilfs_direct *)bmap;
+        struct inode *dat = NULL;
+        __u64 ptr, ptr2;
+        sector_t blocknr;
+        int ret, cnt;
+
+        if (key > NILFS_DIRECT_KEY_MAX ||
+            (ptr = nilfs_direct_get_ptr(direct, key)) ==
+            NILFS_BMAP_INVALID_PTR)
+                return -ENOENT;
+
+        if (NILFS_BMAP_USE_VBN(bmap)) {
+                dat = nilfs_bmap_get_dat(bmap);
+                ret = nilfs_dat_translate(dat, ptr, &blocknr);
+                if (ret < 0)
+                        return ret;
+                ptr = blocknr;
+        }
+
+        maxblocks = min_t(unsigned, maxblocks, NILFS_DIRECT_KEY_MAX - key + 1);
+        for (cnt = 1; cnt < maxblocks &&
+                     (ptr2 = nilfs_direct_get_ptr(direct, key + cnt)) !=
+                     NILFS_BMAP_INVALID_PTR;
+             cnt++) {
+                if (dat) {
+                        ret = nilfs_dat_translate(dat, ptr2, &blocknr);
+                        if (ret < 0)
+                                return ret;
+                        ptr2 = blocknr;
+                }
+                if (ptr2 != ptr + cnt)
+                        break;
+        }
+        *ptrp = ptr;
+        return cnt;
+}
+
 static __u64
 nilfs_direct_find_target_v(const struct nilfs_direct *direct, __u64 key)
 {
@@ -367,6 +409,7 @@ static int nilfs_direct_assign(struct nilfs_bmap *bmap,
 
 static const struct nilfs_bmap_operations nilfs_direct_ops = {
         .bop_lookup             =       nilfs_direct_lookup,
+        .bop_lookup_contig      =       nilfs_direct_lookup_contig,
         .bop_insert             =       nilfs_direct_insert,
         .bop_delete             =       nilfs_direct_delete,
         .bop_clear              =       NULL,