On 3/25/15 5:46 AM, Lukas Czerner wrote:
> Currently we're unable to online resize very small (smaller than 32 MB)
> file systems with 1k block size because there is not enough space in the
> journal to put all the reserved gdt blocks.
So, I'll get to the patch review if I need to, but this all seemed a little
odd; this is a regression, so do we really need to restrict things at mkfs
time?
On the userspace side, things were ok until:
9f6ba88 resize2fs: add support for new in-kernel online resize ioctl
and even with that, on the kernelspace side, things were ok until:
8f7d89f jbd2: transaction reservation support
I guess I'm trying to understand why that jbd2 commit regressed this.
I've not been paying enough attention to ext4 lately. ;)
I mean, the threshold got chopped in half:
- if (nblocks > journal->j_max_transaction_buffers) {
+ /*
+ * 1/2 of transaction can be reserved so we can practically handle
+ * only 1/2 of maximum transaction size per operation
+ */
+ if (WARN_ON(blocks > journal->j_max_transaction_buffers / 2)) {
printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
- current->comm, nblocks,
- journal->j_max_transaction_buffers);
+ current->comm, blocks,
+ journal->j_max_transaction_buffers / 2);
return -ENOSPC;
}
so it's clear why the behavior changed, I guess, but it feels like I
must be missing something here.
The reproducer, for those playing along at home, is something like:
mkfs.ext4 /dev/sda 20M
mount /dev/sda /mnt/test
resize2fs /dev/sda 200M
-Eric
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