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libext2fs: find/alloc a range of empty blocks
[tools/e2fsprogs.git] / lib / ext2fs / alloc.c
index be2b56b..4c3b620 100644 (file)
@@ -4,12 +4,12 @@
  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
  *
  * %Begin-Header%
- * This file may be redistributed under the terms of the GNU Public
- * License.
+ * This file may be redistributed under the terms of the GNU Library
+ * General Public License, version 2.
  * %End-Header%
- *
  */
 
+#include "config.h"
 #include <stdio.h>
 #if HAVE_UNISTD_H
 #include <unistd.h>
 #include "ext2_fs.h"
 #include "ext2fs.h"
 
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
+#undef DEBUG
+
+#ifdef DEBUG
+# define dbg_printf(f, a...)  do {printf(f, ## a); fflush(stdout); } while (0)
+#else
+# define dbg_printf(f, a...)
+#endif
+
 /*
- * Check for uninit block bitmaps and deal with them appropriately
+ * Clear the uninit block bitmap flag if necessary
  */
-static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
-                         dgrp_t group)
+static void clear_block_uninit(ext2_filsys fs, dgrp_t group)
 {
-       blk_t           i;
-       blk_t           blk, super_blk, old_desc_blk, new_desc_blk;
-       int             old_desc_blocks;
-
-       if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
-                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
-           !(fs->group_desc[group].bg_flags & EXT2_BG_BLOCK_UNINIT))
+       if (!ext2fs_has_group_desc_csum(fs) ||
+           !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
                return;
 
-       blk = (group * fs->super->s_blocks_per_group) +
-               fs->super->s_first_data_block;
-
-       ext2fs_super_and_bgd_loc(fs, group, &super_blk,
-                                &old_desc_blk, &new_desc_blk, 0);
-
-       if (fs->super->s_feature_incompat &
-           EXT2_FEATURE_INCOMPAT_META_BG)
-               old_desc_blocks = fs->super->s_first_meta_bg;
-       else
-               old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
-
-       for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
-               if ((blk == super_blk) ||
-                   (old_desc_blk && old_desc_blocks &&
-                    (blk >= old_desc_blk) &&
-                    (blk < old_desc_blk + old_desc_blocks)) ||
-                   (new_desc_blk && (blk == new_desc_blk)) ||
-                   (blk == fs->group_desc[group].bg_block_bitmap) ||
-                   (blk == fs->group_desc[group].bg_inode_bitmap) ||
-                   (blk >= fs->group_desc[group].bg_inode_table &&
-                    (blk < fs->group_desc[group].bg_inode_table
-                     + fs->inode_blocks_per_group)))
-                       ext2fs_fast_mark_block_bitmap(map, blk);
-               else
-                       ext2fs_fast_unmark_block_bitmap(map, blk);
-       }
-       fs->group_desc[group].bg_flags &= ~EXT2_BG_BLOCK_UNINIT;
+       /* uninit block bitmaps are now initialized in read_bitmaps() */
+
+       ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
        ext2fs_group_desc_csum_set(fs, group);
+       ext2fs_mark_super_dirty(fs);
+       ext2fs_mark_bb_dirty(fs);
 }
 
 /*
@@ -80,17 +61,20 @@ static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
 {
        ext2_ino_t      i, ino;
 
-       if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
-                                        EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
-           !(fs->group_desc[group].bg_flags & EXT2_BG_INODE_UNINIT))
+       if (!ext2fs_has_group_desc_csum(fs) ||
+           !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
                return;
 
        ino = (group * fs->super->s_inodes_per_group) + 1;
        for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
-               ext2fs_fast_unmark_inode_bitmap(map, ino);
+               ext2fs_fast_unmark_inode_bitmap2(map, ino);
 
-       fs->group_desc[group].bg_flags &= ~EXT2_BG_INODE_UNINIT;
-       check_block_uninit(fs, fs->block_map, group);
+       ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
+       /* Mimics what the kernel does */
+       ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
+       ext2fs_group_desc_csum_set(fs, group);
+       ext2fs_mark_ib_dirty(fs);
+       ext2fs_mark_super_dirty(fs);
 }
 
 /*
@@ -103,9 +87,10 @@ errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
                           int mode EXT2FS_ATTR((unused)),
                           ext2fs_inode_bitmap map, ext2_ino_t *ret)
 {
-       ext2_ino_t      dir_group = 0;
-       ext2_ino_t      i;
-       ext2_ino_t      start_inode;
+       ext2_ino_t      start_inode = 0;
+       ext2_ino_t      i, ino_in_group, upto, first_zero;
+       errcode_t       retval;
+       dgrp_t          group;
 
        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 
@@ -114,27 +99,40 @@ errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
        if (!map)
                return EXT2_ET_NO_INODE_BITMAP;
 
-       if (dir > 0)
-               dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
-
-       start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
+       if (dir > 0) {
+               group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
+               start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
+       }
        if (start_inode < EXT2_FIRST_INODE(fs->super))
                start_inode = EXT2_FIRST_INODE(fs->super);
+       if (start_inode > fs->super->s_inodes_count)
+               return EXT2_ET_INODE_ALLOC_FAIL;
        i = start_inode;
-
        do {
-               if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
-                       check_inode_uninit(fs, map, (i - 1) /
-                                          EXT2_INODES_PER_GROUP(fs->super));
-
-               if (!ext2fs_fast_test_inode_bitmap(map, i))
+               ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
+               group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
+
+               check_inode_uninit(fs, map, group);
+               upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
+               if (i < start_inode && upto >= start_inode)
+                       upto = start_inode - 1;
+               if (upto > fs->super->s_inodes_count)
+                       upto = fs->super->s_inodes_count;
+
+               retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
+                                                             &first_zero);
+               if (retval == 0) {
+                       i = first_zero;
                        break;
-               i++;
+               }
+               if (retval != ENOENT)
+                       return EXT2_ET_INODE_ALLOC_FAIL;
+               i = upto + 1;
                if (i > fs->super->s_inodes_count)
                        i = EXT2_FIRST_INODE(fs->super);
        } while (i != start_inode);
 
-       if (ext2fs_test_inode_bitmap(map, i))
+       if (ext2fs_test_inode_bitmap2(map, i))
                return EXT2_ET_INODE_ALLOC_FAIL;
        *ret = i;
        return 0;
@@ -144,67 +142,77 @@ errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
  * Stupid algorithm --- we now just search forward starting from the
  * goal.  Should put in a smarter one someday....
  */
-errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
-                          ext2fs_block_bitmap map, blk_t *ret)
+errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
+                          ext2fs_block_bitmap map, blk64_t *ret)
 {
-       blk_t   i;
+       errcode_t retval;
+       blk64_t b = 0;
+       errcode_t (*gab)(ext2_filsys fs, blk64_t goal, blk64_t *ret);
 
        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 
+       if (!map && fs->get_alloc_block) {
+               /*
+                * In case there are clients out there whose get_alloc_block
+                * handlers call ext2fs_new_block2 with a NULL block map,
+                * temporarily swap out the function pointer so that we don't
+                * end up in an infinite loop.
+                */
+               gab = fs->get_alloc_block;
+               fs->get_alloc_block = NULL;
+               retval = gab(fs, goal, &b);
+               fs->get_alloc_block = gab;
+               goto allocated;
+       }
        if (!map)
                map = fs->block_map;
        if (!map)
                return EXT2_ET_NO_BLOCK_BITMAP;
-       if (!goal || (goal >= fs->super->s_blocks_count))
+       if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
                goal = fs->super->s_first_data_block;
-       i = goal;
-       check_block_uninit(fs, map,
-                          (i - fs->super->s_first_data_block) /
-                          EXT2_BLOCKS_PER_GROUP(fs->super));
-       do {
-               if (((i - fs->super->s_first_data_block) %
-                    EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
-                       check_block_uninit(fs, map,
-                                          (i - fs->super->s_first_data_block) /
-                                          EXT2_BLOCKS_PER_GROUP(fs->super));
-
-               if (!ext2fs_fast_test_block_bitmap(map, i)) {
-                       *ret = i;
-                       return 0;
-               }
-               i++;
-               if (i >= fs->super->s_blocks_count)
-                       i = fs->super->s_first_data_block;
-       } while (i != goal);
-       return EXT2_ET_BLOCK_ALLOC_FAIL;
+       goal &= ~EXT2FS_CLUSTER_MASK(fs);
+
+       retval = ext2fs_find_first_zero_block_bitmap2(map,
+                       goal, ext2fs_blocks_count(fs->super) - 1, &b);
+       if ((retval == ENOENT) && (goal != fs->super->s_first_data_block))
+               retval = ext2fs_find_first_zero_block_bitmap2(map,
+                       fs->super->s_first_data_block, goal - 1, &b);
+allocated:
+       if (retval == ENOENT)
+               return EXT2_ET_BLOCK_ALLOC_FAIL;
+       if (retval)
+               return retval;
+
+       clear_block_uninit(fs, ext2fs_group_of_blk2(fs, b));
+       *ret = b;
+       return 0;
+}
+
+errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
+                          ext2fs_block_bitmap map, blk_t *ret)
+{
+       errcode_t retval;
+       blk64_t val;
+       retval = ext2fs_new_block2(fs, goal, map, &val);
+       if (!retval)
+               *ret = (blk_t) val;
+       return retval;
 }
 
 /*
  * This function zeros out the allocated block, and updates all of the
  * appropriate filesystem records.
  */
-errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
-                            char *block_buf, blk_t *ret)
+errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
+                            char *block_buf, blk64_t *ret)
 {
        errcode_t       retval;
-       blk_t           block;
-       char            *buf = 0;
-
-       if (!block_buf) {
-               retval = ext2fs_get_mem(fs->blocksize, &buf);
-               if (retval)
-                       return retval;
-               block_buf = buf;
-       }
-       memset(block_buf, 0, fs->blocksize);
+       blk64_t         block;
 
        if (fs->get_alloc_block) {
-               blk64_t new;
-
-               retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new);
+               retval = (fs->get_alloc_block)(fs, goal, &block);
                if (retval)
                        goto fail;
-               block = (blk_t) new;
        } else {
                if (!fs->block_map) {
                        retval = ext2fs_read_block_bitmap(fs);
@@ -212,28 +220,42 @@ errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
                                goto fail;
                }
 
-               retval = ext2fs_new_block(fs, goal, 0, &block);
+               retval = ext2fs_new_block2(fs, goal, 0, &block);
                if (retval)
                        goto fail;
        }
 
-       retval = io_channel_write_blk(fs->io, block, 1, block_buf);
+       if (block_buf) {
+               memset(block_buf, 0, fs->blocksize);
+               retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
+       } else
+               retval = ext2fs_zero_blocks2(fs, block, 1, NULL, NULL);
        if (retval)
                goto fail;
 
-       ext2fs_block_alloc_stats(fs, block, +1);
+       ext2fs_block_alloc_stats2(fs, block, +1);
        *ret = block;
 
 fail:
-       if (buf)
-               ext2fs_free_mem(&buf);
        return retval;
 }
 
-errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
-                                int num, ext2fs_block_bitmap map, blk_t *ret)
+errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
+                            char *block_buf, blk_t *ret)
 {
-       blk_t   b = start;
+       errcode_t retval;
+       blk64_t val;
+       retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
+       if (!retval)
+               *ret = (blk_t) val;
+       return retval;
+}
+
+errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
+                                int num, ext2fs_block_bitmap map, blk64_t *ret)
+{
+       blk64_t b = start;
+       int     c_ratio;
 
        EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
 
@@ -247,18 +269,35 @@ errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
                finish = start;
        if (!num)
                num = 1;
+       c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
+       b &= ~(c_ratio - 1);
+       finish &= ~(c_ratio -1);
        do {
-               if (b+num-1 > fs->super->s_blocks_count)
+               if (b + num - 1 >= ext2fs_blocks_count(fs->super)) {
+                       if (finish > start)
+                               return EXT2_ET_BLOCK_ALLOC_FAIL;
                        b = fs->super->s_first_data_block;
-               if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
+               }
+               if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
                        *ret = b;
                        return 0;
                }
-               b++;
+               b += c_ratio;
        } while (b != finish);
        return EXT2_ET_BLOCK_ALLOC_FAIL;
 }
 
+errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
+                                int num, ext2fs_block_bitmap map, blk_t *ret)
+{
+       errcode_t retval;
+       blk64_t val;
+       retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
+       if(!retval)
+               *ret = (blk_t) val;
+       return retval;
+}
+
 void ext2fs_set_alloc_block_callback(ext2_filsys fs,
                                     errcode_t (*func)(ext2_filsys fs,
                                                       blk64_t goal,
@@ -275,3 +314,176 @@ void ext2fs_set_alloc_block_callback(ext2_filsys fs,
 
        fs->get_alloc_block = func;
 }
+
+blk64_t ext2fs_find_inode_goal(ext2_filsys fs, ext2_ino_t ino,
+                              struct ext2_inode *inode, blk64_t lblk)
+{
+       dgrp_t                  group;
+       __u8                    log_flex;
+       struct ext2fs_extent    extent;
+       ext2_extent_handle_t    handle = NULL;
+       errcode_t               err;
+
+       if (inode == NULL || ext2fs_inode_data_blocks2(fs, inode) == 0)
+               goto no_blocks;
+
+       if (inode->i_flags & EXT4_INLINE_DATA_FL)
+               goto no_blocks;
+
+       if (inode->i_flags & EXT4_EXTENTS_FL) {
+               err = ext2fs_extent_open2(fs, ino, inode, &handle);
+               if (err)
+                       goto no_blocks;
+               err = ext2fs_extent_goto2(handle, 0, lblk);
+               if (err)
+                       goto no_blocks;
+               err = ext2fs_extent_get(handle, EXT2_EXTENT_CURRENT, &extent);
+               if (err)
+                       goto no_blocks;
+               ext2fs_extent_free(handle);
+               return extent.e_pblk + (lblk - extent.e_lblk);
+       }
+
+       /* block mapped file; see if block zero is mapped? */
+       if (inode->i_block[0])
+               return inode->i_block[0];
+
+no_blocks:
+       ext2fs_extent_free(handle);
+       log_flex = fs->super->s_log_groups_per_flex;
+       group = ext2fs_group_of_ino(fs, ino);
+       if (log_flex)
+               group = group & ~((1 << (log_flex)) - 1);
+       return ext2fs_group_first_block2(fs, group);
+}
+
+/*
+ * Starting at _goal_, scan around the filesystem to find a run of free blocks
+ * that's at least _len_ blocks long.  Possible flags:
+ * - EXT2_NEWRANGE_EXACT_GOAL: The range of blocks must start at _goal_.
+ * - EXT2_NEWRANGE_MIN_LENGTH: do not return a allocation shorter than _len_.
+ * - EXT2_NEWRANGE_ZERO_BLOCKS: Zero blocks pblk to pblk+plen before returning.
+ *
+ * The starting block is returned in _pblk_ and the length is returned via
+ * _plen_.  The blocks are not marked in the bitmap; the caller must mark
+ * however much of the returned run they actually use, hopefully via
+ * ext2fs_block_alloc_stats_range().
+ *
+ * This function can return a range that is longer than what was requested.
+ */
+errcode_t ext2fs_new_range(ext2_filsys fs, int flags, blk64_t goal,
+                          blk64_t len, ext2fs_block_bitmap map, blk64_t *pblk,
+                          blk64_t *plen)
+{
+       errcode_t retval;
+       blk64_t start, end, b;
+       int looped = 0;
+       blk64_t max_blocks = ext2fs_blocks_count(fs->super);
+
+       dbg_printf("%s: flags=0x%x goal=%llu len=%llu\n", __func__, flags,
+                  goal, len);
+       EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+       if (len == 0 || (flags & ~EXT2_NEWRANGE_ALL_FLAGS))
+               return EXT2_ET_INVALID_ARGUMENT;
+       if (!map)
+               map = fs->block_map;
+       if (!map)
+               return EXT2_ET_NO_BLOCK_BITMAP;
+       if (!goal || goal >= ext2fs_blocks_count(fs->super))
+               goal = fs->super->s_first_data_block;
+
+       start = goal;
+       while (!looped || start <= goal) {
+               retval = ext2fs_find_first_zero_block_bitmap2(map, start,
+                                                             max_blocks - 1,
+                                                             &start);
+               if (retval == ENOENT) {
+                       /*
+                        * If there are no free blocks beyond the starting
+                        * point, try scanning the whole filesystem, unless the
+                        * user told us only to allocate from _goal_, or if
+                        * we're already scanning the whole filesystem.
+                        */
+                       if (flags & EXT2_NEWRANGE_FIXED_GOAL ||
+                           start == fs->super->s_first_data_block)
+                               goto fail;
+                       start = fs->super->s_first_data_block;
+                       continue;
+               } else if (retval)
+                       goto errout;
+
+               if (flags & EXT2_NEWRANGE_FIXED_GOAL && start != goal)
+                       goto fail;
+
+               b = min(start + len - 1, max_blocks - 1);
+               retval =  ext2fs_find_first_set_block_bitmap2(map, start, b,
+                                                             &end);
+               if (retval == ENOENT)
+                       end = b + 1;
+               else if (retval)
+                       goto errout;
+
+               if (!(flags & EXT2_NEWRANGE_MIN_LENGTH) ||
+                   (end - start) >= len) {
+                       /* Success! */
+                       *pblk = start;
+                       *plen = end - start;
+                       dbg_printf("%s: new_range goal=%llu--%llu "
+                                  "blk=%llu--%llu %llu\n",
+                                  __func__, goal, goal + len - 1,
+                                  *pblk, *pblk + *plen - 1, *plen);
+
+                       for (b = start; b < end;
+                            b += fs->super->s_blocks_per_group)
+                               clear_block_uninit(fs,
+                                               ext2fs_group_of_blk2(fs, b));
+                       return 0;
+               }
+
+               if (flags & EXT2_NEWRANGE_FIXED_GOAL)
+                       goto fail;
+               start = end;
+               if (start >= max_blocks) {
+                       if (looped)
+                               goto fail;
+                       looped = 1;
+                       start = fs->super->s_first_data_block;
+               }
+       }
+
+fail:
+       retval = EXT2_ET_BLOCK_ALLOC_FAIL;
+errout:
+       return retval;
+}
+
+errcode_t ext2fs_alloc_range(ext2_filsys fs, int flags, blk64_t goal,
+                            blk_t len, blk64_t *ret)
+{
+       int newr_flags = EXT2_NEWRANGE_MIN_LENGTH;
+       errcode_t retval;
+       blk64_t plen;
+
+       EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+       if (len == 0 || (flags & ~EXT2_ALLOCRANGE_ALL_FLAGS))
+               return EXT2_ET_INVALID_ARGUMENT;
+
+       if (flags & EXT2_ALLOCRANGE_FIXED_GOAL)
+               newr_flags |= EXT2_NEWRANGE_FIXED_GOAL;
+
+       retval = ext2fs_new_range(fs, newr_flags, goal, len, NULL, ret, &plen);
+       if (retval)
+               return retval;
+
+       if (plen < len)
+               return EXT2_ET_BLOCK_ALLOC_FAIL;
+
+       if (flags & EXT2_ALLOCRANGE_ZERO_BLOCKS) {
+               retval = ext2fs_zero_blocks2(fs, *ret, len, NULL, NULL);
+               if (retval)
+                       return retval;
+       }
+
+       ext2fs_block_alloc_stats_range(fs, *ret, len, +1);
+       return retval;
+}