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ext2: Support META_BG.

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This fixes bug that system would become unbootable after ext*
online resize if no resize_inode was created at ext* format time.
This commit is contained in:
Vladimir Serbinenko 2015-02-16 20:53:26 +01:00
parent 35a492e4a2
commit e20aa39ea4
3 changed files with 63 additions and 5 deletions
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61
grub-core/fs/ext2.c
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@ -107,6 +107,7 @@ GRUB_MOD_LICENSE ("GPLv3+");
#define EXT2_DRIVER_SUPPORTED_INCOMPAT ( EXT2_FEATURE_INCOMPAT_FILETYPE \
| EXT4_FEATURE_INCOMPAT_EXTENTS \
| EXT4_FEATURE_INCOMPAT_FLEX_BG \
| EXT2_FEATURE_INCOMPAT_META_BG \
| EXT4_FEATURE_INCOMPAT_64BIT)
/* List of rationales for the ignored "incompatible" features:
* needs_recovery: Not really back-incompatible - was added as such to forbid
@ -331,16 +332,68 @@ static grub_dl_t my_mod;
/* Check is a = b^x for some x. */
static inline int
is_power_of (grub_uint64_t a, grub_uint32_t b)
{
grub_uint64_t c;
/* Prevent overflow assuming b < 8. */
if (a >= (1LL << 60))
return 0;
for (c = 1; c <= a; c *= b);
return (c == a);
}
static inline int
group_has_super_block (struct grub_ext2_data *data, grub_uint64_t group)
{
if (!(data->sblock.feature_ro_compat
& grub_cpu_to_le32_compile_time(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)))
return 1;
/* Algorithm looked up in Linux source. */
if (group <= 1)
return 1;
/* Even number is never a power of odd number. */
if (!(group & 1))
return 0;
return (is_power_of(group, 7) || is_power_of(group, 5) ||
is_power_of(group, 3));
}
/* Read into BLKGRP the blockgroup descriptor of blockgroup GROUP of
the mounted filesystem DATA. */
inline static grub_err_t
grub_ext2_blockgroup (struct grub_ext2_data *data, int group,
grub_ext2_blockgroup (struct grub_ext2_data *data, grub_uint64_t group,
struct grub_ext2_block_group *blkgrp)
{
grub_uint64_t full_offset = (group << data->log_group_desc_size);
grub_uint64_t block, offset;
block = (full_offset >> LOG2_BLOCK_SIZE (data));
offset = (full_offset & ((1 << LOG2_BLOCK_SIZE (data)) - 1));
if ((data->sblock.feature_incompat
& grub_cpu_to_le32_compile_time (EXT2_FEATURE_INCOMPAT_META_BG))
&& block >= grub_le_to_cpu32(data->sblock.first_meta_bg))
{
grub_uint64_t first_block_group;
/* Find the first block group for which a descriptor
is stored in given block. */
first_block_group = (block << (LOG2_BLOCK_SIZE (data)
- data->log_group_desc_size));
block = (first_block_group
* grub_le_to_cpu32(data->sblock.blocks_per_group));
if (group_has_super_block (data, first_block_group))
block++;
}
else
/* Superblock. */
block++;
return grub_disk_read (data->disk,
((grub_le_to_cpu32 (data->sblock.first_data_block) + 1)
<< LOG2_EXT2_BLOCK_SIZE (data)),
group << data->log_group_desc_size,
((grub_le_to_cpu32 (data->sblock.first_data_block)
+ block)
<< LOG2_EXT2_BLOCK_SIZE (data)), offset,
sizeof (struct grub_ext2_block_group), blkgrp);
}