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, 25 insertions, 10 deletions

diff --git a/ext2fs/hyper.c b/ext2fs/hyper.c
index bee4175f..5bcc2abe 100644
--- a/ext2fs/hyper.c
+++ b/ext2fs/hyper.c
@@ -58,11 +58,14 @@ static int ext2fs_clean;	/* fs clean before we started writing? */
 void
 get_hypermetadata (void)
 {
-  error_t err = diskfs_catch_exception ();
-  if (err)
-    ext2_panic ("can't read superblock: %s", strerror (err));
+  error_t err;
+  size_t read = 0;
 
-  sblock = (struct ext2_super_block *) boffs_ptr (SBLOCK_OFFS);
+  assert (! sblock);
+  err = store_read (store, SBLOCK_OFFS >> store->log2_block_size,
+		    SBLOCK_SIZE, (void **)&sblock, &read);
+  if (err || read != SBLOCK_SIZE)
+    ext2_panic ("Cannot read hypermetadata");
 
   if (sblock->s_magic != EXT2_SUPER_MAGIC
 #ifdef EXT2FS_PRE_02B_COMPAT
@@ -152,15 +155,25 @@ get_hypermetadata (void)
 
   allocate_mod_map ();
 
-  diskfs_end_catch_exception ();
+  /* A handy source of page-aligned zeros.  */
+  if (zeroblock == 0)
+    {
+      zeroblock = (vm_address_t) mmap (0, block_size, PROT_READ, MAP_ANON, 0, 0);
+      assert (zeroblock != (vm_address_t) MAP_FAILED);
+    }
+
+  munmap (sblock, SBLOCK_SIZE);
+  sblock = NULL;
+}
+
+void
+map_hypermetadata (void)
+{
+  sblock = (struct ext2_super_block *) boffs_ptr (SBLOCK_OFFS);
 
   /* Cache a convenient pointer to the block group descriptors for allocation.
      These are stored in the filesystem blocks following the superblock.  */
   group_desc_image = (struct ext2_group_desc *) bptr (bptr_block (sblock) + 1);
-
-  /* A handy source of page-aligned zeros.  */
-  if (zeroblock == 0)
-    zeroblock = (vm_address_t) mmap (0, block_size, PROT_READ, MAP_ANON, 0, 0);
 }
 
 error_t
@@ -183,6 +196,7 @@ diskfs_set_hypermetadata (int wait, int clean)
  if (sblock_dirty)
    {
      sblock_dirty = 0;
+     disk_cache_block_ref_ptr (sblock);
      record_global_poke (sblock);
    }
 
@@ -199,7 +213,8 @@ diskfs_readonly_changed (int readonly)
 
   (*(readonly ? store_set_flags : store_clear_flags)) (store, STORE_READONLY);
 
-  mprotect (disk_image, store->size, PROT_READ | (readonly ? 0 : PROT_WRITE));
+  mprotect (disk_cache, disk_cache_size,
+	    PROT_READ | (readonly ? 0 : PROT_WRITE));
 
   if (!readonly && !(sblock->s_state & EXT2_VALID_FS))
     ext2_warning ("UNCLEANED FILESYSTEM NOW WRITABLE");