vitalif
/
e2fsprogs
mirror of https://github.com/vitalif/e2fsprogs
1
0
Fork 0
Code Issues Releases Wiki Activity

Revert "mke2fs: prevent creation of unmountable ext4 with large flex_bg count" 

This reverts commit d988201ef9.

The problem with this commit is that causes common small file system
configurations to fail.  For example:

    mke2fs -O flex_bg -b 4096 -I 1024 -F /tmp/tt 79106
    mke2fs 1.42.11 (09-Jul-2014)
    /tmp/tt: Invalid argument passed to ext2 library while setting
             up superblock

This check in ext2fs_initialize() was added to prevent the metadata
from being allocated beyond the end of the filesystem, but it is
also causing a wide range of failures for small filesystems.

We'll address this in a different way, by using a smarter algorithm
for deciding the layout of metadata blocks for the last flex block
group.

Reported-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
test-maint
Theodore Ts'o 2014-08-03 12:22:27 -04:00
parent bf140bf298
commit 457e49981e
1 changed files with 0 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
lib/ext2fs/initialize.c
View File

@ -91,10 +91,8 @@ errcode_t ext2fs_initialize(const char *name, int flags,
unsigned int rem;
unsigned int overhead = 0;
unsigned int ipg;
unsigned int flexbg_size;
dgrp_t i;
blk64_t free_blocks;
blk64_t flexbg_overhead;
blk_t numblocks;
int rsv_gdt;
int csum_flag;
@ -420,28 +418,6 @@ ipg_retry:
goto retry;
}
/*
* Calculate the flex_bg related metadata blocks count.
* It includes the boot block, the super block,
* the block group descriptors, the reserved gdt blocks,
* the block bitmaps, the inode bitmaps and the inode tables.
* This is a simple check, so that the backup superblock and
* other feature related blocks are not considered.
*/
flexbg_size = 1 << fs->super->s_log_groups_per_flex;
flexbg_overhead = super->s_first_data_block + 1 +
fs->desc_blocks + super->s_reserved_gdt_blocks +
(__u64)flexbg_size * (2 + fs->inode_blocks_per_group);
/*
* Disallow creating ext4 which breaks flex_bg metadata layout
* obviously.
*/
if (flexbg_overhead > ext2fs_blocks_count(fs->super)) {
retval = EXT2_ET_INVALID_ARGUMENT;
goto cleanup;
}
/*
* At this point we know how big the filesystem will be. So
* we can do any and all allocations that depend on the block