Large store support for ext2fs

This is a revised version of the large store patch for ext2fs, written
by Ognyan Kulev. It provides support for stores larger than 2 GiB.

* ext2fs/balloc.c: Use the new disk_cache_block_ref and disk_cache_block_deref
functions to access blocks from the disk cache.
* ext2fs/ext2fs.c (main): Update initialization call to pokel_init, and
call map_hypermetadata instead of get_hypermetadata.
* ext2fs/ext2fs.h: Include <hurd/store.h> and <hurd/ihash.h>.
(DISK_CACHE_BLOCKS): New macro.
(DC_INCORE): Likewise.
(DC_UNTOUCHED): Likewise.
(DC_FIXED): Likewise.
(DC_DONT_REUSE): Likewise.
(DC_NO_BLOCK): Likewise.
(DISK_CACHE_LAST_READ_XOR) [!NDEBUG]: Likewise.
(struct disk_cache_info): New structure.
(disk_cache): New external variable.
(disk_cache_size): Likewise.
(disk_cache_blocks): Likewise.
(disk_cache_bptr): Likewise.
(disk_cache_info): Likewise.
(disk_cache_lock): Likewise.
(disk_cache_reassociation): Likewise.
(disk_cache_block_ref): New declaration.
(disk_cache_block_ref_ptr): Likewise.
(disk_cache_block_deref): Likewise.
(disk_cache_block_is_ref): Likewise.
(map_hypermetadata): Likewise.
(trunc_block): Cast to off_t.
(round_block): Likewise.
(boffs): Likewise.
(bptr_index): New macro.
(boffs_ptr): Rewrite as an inline function to make it look up a block from
the disk cache.
(bptr_offs): Likewise.
(dino): Remove function, replaced with ...
(dino_ref): ... this one, which adds a reference to the inode block.
(dino_deref): New inline function.
(record_global_poke): Make sure block is referenced.
(record_indir_poke): Likewise.
(sync_global_ptr): Remove block reference, and adjust call to
pager_sync_some.
(sync_global): Add debug call to print wait parameter.
* ext2fs/getblk.c: Use the new disk_cache_block_ref and disk_cache_block_deref
functions to access blocks from the disk cache.
* ext2fs/hyper.c (get_hypermetadata): Read the superblock from the store
now that it's not directly mapped in memory. Move the initialization of
zeroblock here from ...
(map_hypermetadata): ... here. Also, set the superblock pointer.
(diskfs_set_hypermetadata): Add a reference to the superblock.
(diskfs_readonly_changed): Update call to mprotect.
* ext2fs/ialloc.c: Use the new disk_cache_block_ref, disk_cache_block_ref_ptr
and disk_cache_block_deref functions to access blocks from the disk cache.
* ext2fs/inode.c: Update calls that used the disk image to use the disk cache,
and use the new reference handling functions where appropriate.
* ext2fs/pager.c: Include <unistd.h> and "../libpager/priv.h".
(disk_image): Remove global variable.
(disk_pager_read_page): Update cache information.
(disk_pager_write_page): Likewise.
(disk_pager_notify_evict): New function.
(pager_notify_evict): Call disk_pager_notify_evict appropriately.
(disk_cache): New global variable.
(disk_cache_size): Likewise.
(disk_cache_blocks): Likewise.
(disk_cache_bptr): Likewise.
(disk_cache_info): Likewise.
(disk_cache_hint): Likewise.
(disk_cache_lock): Likewise.
(disk_cache_reassociation): Likewise.
(disk_cache_init): New function.
(disk_cache_return_unused): Likewise.
(disk_cache_block_ref): Likewise.
(disk_cache_block_ref_ptr): Likewise.
(disk_cache_block_deref): Likewise.
(disk_cache_block_is_ref): Likewise.
(create_disk_pager): Update initialization of the disk pager.
* ext2fs/pokel.c (pokel_add): Drop block references with disk_cache_block_deref.
(_pokel_exec): Likewise.
* ext2fs/truncate.c (trunc_indirect): Use the new disk_cache_block_ref and
disk_cache_block_deref functions to access blocks from the disk cache.

1 files changed, 16 insertions, 5 deletions

diff --git a/ext2fs/getblk.c b/ext2fs/getblk.c
index 23ba6459..bde66e1c 100644
--- a/ext2fs/getblk.c
+++ b/ext2fs/getblk.c
@@ -104,7 +104,7 @@ ext2_alloc_block (struct node *node, block_t goal, int zero)
 
   if (result && zero)
     {
-      char *bh = bptr (result);
+      char *bh = disk_cache_block_ref (result);
       bzero (bh, block_size);
       record_indir_poke (node, bh);
     }
@@ -122,6 +122,8 @@ inode_getblk (struct node *node, int nr, int create, int zero,
   block_t hint;
 #endif
 
+  assert (0 <= nr && nr < EXT2_N_BLOCKS);
+
   *result = node->dn->info.i_data[nr];
   if (*result)
     return 0;
@@ -180,14 +182,20 @@ block_getblk (struct node *node, block_t block, int nr, int create, int zero,
 {
   int i;
   block_t goal = 0;
-  block_t *bh = (block_t *)bptr (block);
+  block_t *bh = (block_t *)disk_cache_block_ref (block);
 
   *result = bh[nr];
   if (*result)
-    return 0;
+    {
+      disk_cache_block_deref (bh);
+      return 0;
+    }
 
   if (!create)
-    return EINVAL;
+    {
+      disk_cache_block_deref (bh);
+      return EINVAL;
+    }
 
   if (node->dn->info.i_next_alloc_block == new_block)
     goal = node->dn->info.i_next_alloc_goal;
@@ -207,7 +215,10 @@ block_getblk (struct node *node, block_t block, int nr, int create, int zero,
 
   *result = ext2_alloc_block (node, goal, zero);
   if (!*result)
-    return ENOSPC;
+    {
+      disk_cache_block_deref (bh);
+      return ENOSPC;
+    }
 
   bh[nr] = *result;