From: Omar Sandoval <[email protected]> First, instead of open-coding the vmalloc() fallback, use the new kvzalloc() helper. Second, use memalloc_nofs_{save,restore}() instead of GFP_NOFS, as vmalloc() uses some GFP_KERNEL allocations internally which could lead to deadlocks.
Signed-off-by: Omar Sandoval <[email protected]> --- fs/btrfs/free-space-tree.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index fc0bd8406758..e5e92e6ba734 100644 --- a/fs/btrfs/free-space-tree.c +++ b/fs/btrfs/free-space-tree.c @@ -17,7 +17,7 @@ */ #include <linux/kernel.h> -#include <linux/vmalloc.h> +#include <linux/sched/mm.h> #include "ctree.h" #include "disk-io.h" #include "locking.h" @@ -153,21 +153,21 @@ 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. + * + * TODO: push the memalloc_nofs_{save,restore}() to the caller where we + * know that recursion is unsafe. */ - 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 = kvzalloc(bitmap_size, GFP_KERNEL); + memalloc_nofs_restore(nofs_flag); + return ret; } int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans, -- 2.13.0 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
