On Wed, May 31, 2017 at 02:29:20AM -0700, Omar Sandoval wrote:
> diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
> index fc0bd8406758..5abd3cd71144 100644
> --- a/fs/btrfs/free-space-tree.c
> +++ b/fs/btrfs/free-space-tree.c
> @@ -153,21 +153,18 @@ static inline u32 free_space_bitmap_size(u64 size, u32
> sectorsize)
>
> static u8 *alloc_bitmap(u32 bitmap_size)
> {
> - void *mem;
> + u8 *ret;
> + unsigned int nofs_flag;
>
> /*
> - * The allocation size varies, observed numbers were < 4K up to 16K.
> - * Using vmalloc unconditionally would be too heavy, we'll try
> - * contiguous allocations first.
> + * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
> + * into the filesystem as the free space bitmap can be modified in the
> + * critical section of a transaction commit.
> */
> - if (bitmap_size <= PAGE_SIZE)
> - return kzalloc(bitmap_size, GFP_NOFS);
> -
> - mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
> - if (mem)
> - return mem;
> -
> - return __vmalloc(bitmap_size, GFP_NOFS | __GFP_ZERO, PAGE_KERNEL);
> + nofs_flag = memalloc_nofs_save();
> + ret = kvmalloc(bitmap_size, GFP_KERNEL);
> + memalloc_nofs_restore(nofs_flag);
> + return ret;
> }
>
> int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
>
> Dave, would you prefer to replace the patch we have now or do an
> incremental patch on top of it?
I'll drop the patch "btrfs: Use kvzalloc instead of kzalloc/vmalloc in
alloc_bitmap", please send an updated version.
