| Message ID | 1556227470-47076-1-git-send-email-adilger@dilger.ca |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | mke2fs: fix check for absurdly large devices | expand |
On Thu, Apr 25, 2019 at 11:24:30PM +0200, Andreas Dilger wrote: > The check in mke2fs is intended to be for the number of blocks in the > filesystem exceeding the maximum number of addressable blocks in 2^32 > bitmaps, which is (2^32 * 8 bits/byte * blocksize) = 2^47 blocks, > or 2^59 bytes = 512PiB for the common 4KiB blocksize. > > However, s_log_blocksize holds log2(blocksize_in_kb), so the current > calculation is a factor of 2^10 too small. This caused mke2fs to fail > while trying to format a 900TB filesystem. > > Fixes: 101ef2e93c25 ("mke2fs: Avoid crashes / infinite loops for absurdly large devices") > Signed-off-by: Andreas Dilger <adilger@dilger.ca> Thanks, applied. - Ted
diff --git a/misc/mke2fs.c b/misc/mke2fs.c index be3586c..23e313c 100644 --- a/misc/mke2fs.c +++ b/misc/mke2fs.c @@ -2190,9 +2190,11 @@ profile_error: } /* * Guard against group descriptor count overflowing... Mostly to avoid - * strange results for absurdly large devices. + * strange results for absurdly large devices. This is in log2: + * (blocksize) * (bits per byte) * (maximum number of block groups) */ - if (fs_blocks_count > ((1ULL << (fs_param.s_log_block_size + 3 + 32)) - 1)) { + if (fs_blocks_count > + (1ULL << (EXT2_BLOCK_SIZE_BITS(&fs_param) + 3 + 32)) - 1) { fprintf(stderr, _("%s: Size of device (0x%llx blocks) %s " "too big to create\n\t" "a filesystem using a blocksize of %d.\n"),
The check in mke2fs is intended to be for the number of blocks in the filesystem exceeding the maximum number of addressable blocks in 2^32 bitmaps, which is (2^32 * 8 bits/byte * blocksize) = 2^47 blocks, or 2^59 bytes = 512PiB for the common 4KiB blocksize. However, s_log_blocksize holds log2(blocksize_in_kb), so the current calculation is a factor of 2^10 too small. This caused mke2fs to fail while trying to format a 900TB filesystem. Fixes: 101ef2e93c25 ("mke2fs: Avoid crashes / infinite loops for absurdly large devices") Signed-off-by: Andreas Dilger <adilger@dilger.ca> --- misc/mke2fs.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)