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-rw-r--r--ext2fs/getblk.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/ext2fs/getblk.c b/ext2fs/getblk.c
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--- /dev/null
+++ b/ext2fs/getblk.c
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+/* File block to disk block mapping routines
+
+ Copyright (C) 1995,96,99 Free Software Foundation, Inc.
+
+ Converted to work under the hurd by Miles Bader <miles@gnu.org>
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2, or (at
+ your option) any later version.
+
+ This program is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+/*
+ * linux/fs/ext2/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/inode.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Goal-directed block allocation by Stephen Tweedie (sct@dcs.ed.ac.uk), 1993
+ */
+
+#include <string.h>
+#include "ext2fs.h"
+
+/*
+ * ext2_discard_prealloc and ext2_alloc_block are atomic wrt. the
+ * superblock in the same manner as are ext2_free_blocks and
+ * ext2_new_block. We just wait on the super rather than locking it
+ * here, since ext2_new_block will do the necessary locking and we
+ * can't block until then.
+ */
+void
+ext2_discard_prealloc (struct node *node)
+{
+#ifdef EXT2_PREALLOCATE
+ if (node->dn->info.i_prealloc_count)
+ {
+ int i = node->dn->info.i_prealloc_count;
+ ext2_debug ("discarding %d prealloced blocks for inode %d",
+ i, node->cache_id);
+ node->dn->info.i_prealloc_count = 0;
+ ext2_free_blocks (node->dn->info.i_prealloc_block, i);
+ }
+#endif
+}
+
+/* Allocate a new block for the file NODE, as close to block GOAL as
+ possible, and return it, or 0 if none could be had. If ZERO is true, then
+ zero the block (and add it to NODE's list of modified indirect blocks). */
+static block_t
+ext2_alloc_block (struct node *node, block_t goal, int zero)
+{
+#ifdef EXT2FS_DEBUG
+ static unsigned long alloc_hits = 0, alloc_attempts = 0;
+#endif
+ block_t result;
+
+#ifdef EXT2_PREALLOCATE
+ if (node->dn->info.i_prealloc_count &&
+ (goal == node->dn->info.i_prealloc_block ||
+ goal + 1 == node->dn->info.i_prealloc_block))
+ {
+ result = node->dn->info.i_prealloc_block++;
+ node->dn->info.i_prealloc_count--;
+ ext2_debug ("preallocation hit (%lu/%lu) => %lu",
+ ++alloc_hits, ++alloc_attempts, result);
+ }
+ else
+ {
+ ext2_debug ("preallocation miss (%lu/%lu)",
+ alloc_hits, ++alloc_attempts);
+ ext2_discard_prealloc (node);
+ result = ext2_new_block
+ (goal,
+ S_ISREG (node->dn_stat.st_mode)
+ ? (sblock->s_prealloc_blocks ?: EXT2_DEFAULT_PREALLOC_BLOCKS)
+ : (S_ISDIR (node->dn_stat.st_mode)
+ && EXT2_HAS_COMPAT_FEATURE(sblock,
+ EXT2_FEATURE_COMPAT_DIR_PREALLOC))
+ ? sblock->s_prealloc_dir_blocks
+ : 0,
+ &node->dn->info.i_prealloc_count,
+ &node->dn->info.i_prealloc_block);
+ }
+#else
+ result = ext2_new_block (goal, 0, 0);
+#endif
+
+ if (result && zero)
+ {
+ char *bh = bptr (result);
+ bzero (bh, block_size);
+ record_indir_poke (node, bh);
+ }
+
+ return result;
+}
+
+static error_t
+inode_getblk (struct node *node, int nr, int create, int zero,
+ block_t new_block, block_t *result)
+{
+ int i;
+ block_t goal = 0;
+#ifdef EXT2FS_DEBUG
+ block_t hint;
+#endif
+
+ *result = node->dn->info.i_data[nr];
+ if (*result)
+ return 0;
+
+ if (!create)
+ return EINVAL;
+
+ if (node->dn->info.i_next_alloc_block == new_block)
+ goal = node->dn->info.i_next_alloc_goal;
+
+#ifdef EXT2FS_DEBUG
+ hint = goal;
+#endif
+
+ if (!goal)
+ {
+ for (i = nr - 1; i >= 0; i--)
+ {
+ if (node->dn->info.i_data[i])
+ {
+ goal = node->dn->info.i_data[i];
+ break;
+ }
+ }
+ if (!goal)
+ goal =
+ (node->dn->info.i_block_group * EXT2_BLOCKS_PER_GROUP (sblock))
+ + sblock->s_first_data_block;
+ }
+
+ *result = ext2_alloc_block (node, goal, zero);
+
+ ext2_debug ("%screate, hint = %lu, goal = %lu => %lu",
+ create ? "" : "no", hint, goal, *result);
+
+ if (!*result)
+ return ENOSPC;
+
+ node->dn->info.i_data[nr] = *result;
+
+ node->dn->info.i_next_alloc_block = new_block;
+ node->dn->info.i_next_alloc_goal = *result;
+ node->dn_set_ctime = node->dn_set_mtime = 1;
+ node->dn_stat.st_blocks += 1 << log2_stat_blocks_per_fs_block;
+ node->dn_stat_dirty = 1;
+
+ if (diskfs_synchronous || node->dn->info.i_osync)
+ diskfs_node_update (node, 1);
+
+ return 0;
+}
+
+error_t
+block_getblk (struct node *node, block_t block, int nr, int create, int zero,
+ block_t new_block, block_t *result)
+{
+ int i;
+ block_t goal = 0;
+ block_t *bh = (block_t *)bptr (block);
+
+ *result = bh[nr];
+ if (*result)
+ return 0;
+
+ if (!create)
+ return EINVAL;
+
+ if (node->dn->info.i_next_alloc_block == new_block)
+ goal = node->dn->info.i_next_alloc_goal;
+ if (!goal)
+ {
+ for (i = nr - 1; i >= 0; i--)
+ {
+ if (bh[i])
+ {
+ goal = bh[i];
+ break;
+ }
+ }
+ if (!goal)
+ goal = block;
+ }
+
+ *result = ext2_alloc_block (node, goal, zero);
+ if (!*result)
+ return ENOSPC;
+
+ bh[nr] = *result;
+
+ if (diskfs_synchronous || node->dn->info.i_osync)
+ sync_global_ptr (bh, 1);
+ else
+ record_indir_poke (node, bh);
+
+ node->dn->info.i_next_alloc_block = new_block;
+ node->dn->info.i_next_alloc_goal = *result;
+ node->dn_set_ctime = node->dn_set_mtime = 1;
+ node->dn_stat.st_blocks += 1 << log2_stat_blocks_per_fs_block;
+ node->dn_stat_dirty = 1;
+
+ return 0;
+}
+
+/* Returns in DISK_BLOCK the disk block correspding to BLOCK in NODE. If
+ there is no such block yet, but CREATE is true, then it is created,
+ otherwise EINVAL is returned. */
+error_t
+ext2_getblk (struct node *node, block_t block, int create, block_t *disk_block)
+{
+ error_t err;
+ block_t indir, b;
+ unsigned long addr_per_block = EXT2_ADDR_PER_BLOCK (sblock);
+
+ if (block > EXT2_NDIR_BLOCKS + addr_per_block +
+ addr_per_block * addr_per_block +
+ addr_per_block * addr_per_block * addr_per_block)
+ {
+ ext2_warning ("block > big: %u", block);
+ return EIO;
+ }
+ /*
+ * If this is a sequential block allocation, set the next_alloc_block
+ * to this block now so that all the indblock and data block
+ * allocations use the same goal zone
+ */
+
+ ext2_debug ("block = %lu, next = %lu, goal = %lu", block,
+ node->dn->info.i_next_alloc_block,
+ node->dn->info.i_next_alloc_goal);
+
+ if (block == node->dn->info.i_next_alloc_block + 1)
+ {
+ node->dn->info.i_next_alloc_block++;
+ node->dn->info.i_next_alloc_goal++;
+ }
+
+ b = block;
+
+ if (block < EXT2_NDIR_BLOCKS)
+ return inode_getblk (node, block, create, 0, b, disk_block);
+
+ block -= EXT2_NDIR_BLOCKS;
+ if (block < addr_per_block)
+ {
+ err = inode_getblk (node, EXT2_IND_BLOCK, create, 1, b, &indir);
+ if (!err)
+ err = block_getblk (node, indir, block, create, 0, b, disk_block);
+ return err;
+ }
+
+ block -= addr_per_block;
+ if (block < addr_per_block * addr_per_block)
+ {
+ err = inode_getblk (node, EXT2_DIND_BLOCK, create, 1, b, &indir);
+ if (!err)
+ err = block_getblk (node, indir, block / addr_per_block, create, 1,
+ b, &indir);
+ if (!err)
+ err = block_getblk (node, indir, block & (addr_per_block - 1),
+ create, 0, b, disk_block);
+ return err;
+ }
+
+ block -= addr_per_block * addr_per_block;
+ err = inode_getblk (node, EXT2_TIND_BLOCK, create, 1, b, &indir);
+ if (!err)
+ err = block_getblk (node, indir, block / (addr_per_block * addr_per_block),
+ create, 1, b, &indir);
+ if (!err)
+ err =
+ block_getblk (node, indir,
+ (block / addr_per_block) & (addr_per_block - 1),
+ create, 1, b, &indir);
+ if (!err)
+ err = block_getblk (node, indir, block & (addr_per_block - 1), create, 0,
+ b, disk_block);
+
+ return err;
+}
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