diff options
| author | Omar Sandoval <osandov@fb.com> | 2017-06-05 10:12:31 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-06-19 19:26:01 +0300 |
| commit | 25ff17e82f9612dcd1cf4668acb2148e18305507 (patch) | |
| tree | 7266050b74ca54a91eb5bd5065eda3c7fbb93f69 /fs | |
| parent | 4b5faeac4688174fd523f2a22b7d70d5a96842fb (diff) | |
| download | linux-25ff17e82f9612dcd1cf4668acb2148e18305507.tar.xz | |
Btrfs: use memalloc_nofs and kvzalloc() for free space tree bitmaps
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 <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/free-space-tree.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c index c7397b055119..a5e34de06c2f 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, |