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bcachefs: Workaround for kvmalloc() not supporting > INT_MAX allocations

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kvmalloc() doesn't support allocations > INT_MAX, but vmalloc() does -
the limit should be lifted, but we can work around this for now.

A user with a 75 TB filesystem reported the following journal replay
error:
https://github.com/koverstreet/bcachefs/issues/769

In journal replay we have to sort and dedup all the keys from the
journal, which means we need a large contiguous allocation. Given that
the user has 128GB of ram, the 2GB limit on allocation size has become
far too small.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This commit is contained in:
Kent Overstreet 2024-10-19 18:27:09 -04:00
parent 3956ff8bc2
commit f0d3302073
1 changed files with 14 additions and 1 deletions
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15
fs/bcachefs/darray.c
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@ -2,6 +2,7 @@
#include <linux/log2.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include "darray.h"
int __bch2_darray_resize_noprof(darray_char *d, size_t element_size, size_t new_size, gfp_t gfp)
@ -9,7 +10,19 @@ int __bch2_darray_resize_noprof(darray_char *d, size_t element_size, size_t new_
if (new_size > d->size) {
new_size = roundup_pow_of_two(new_size);
void *data = kvmalloc_array_noprof(new_size, element_size, gfp);
/*
* This is a workaround: kvmalloc() doesn't support > INT_MAX
* allocations, but vmalloc() does.
* The limit needs to be lifted from kvmalloc, and when it does
* we'll go back to just using that.
*/
size_t bytes;
if (unlikely(check_mul_overflow(new_size, element_size, &bytes)))
return -ENOMEM;
void *data = likely(bytes < INT_MAX)
? kvmalloc_noprof(bytes, gfp)
: vmalloc_noprof(bytes);
if (!data)
return -ENOMEM;