Add set_extent_dirty_nofail(). This function is equivalent to
set_extent_dirty(), except that it will never fail because of allocation
failure and instead loop forever trying to allocate memory.
If the first allocation attempt fails, a warning will be emitted,
including a call trace. Subsequent failures will suppress this warning.
This was added as a helper function for documentation and auditability.
No future callers should be added.
Signed-off-by: David Rientjes <rientjes@google.com>
---
fs/btrfs/extent-tree.c | 8 ++++----
fs/btrfs/extent_io.c | 19 +++++++++++++++++++
fs/btrfs/extent_io.h | 2 ++
3 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3831,9 +3831,9 @@ static int update_block_group(struct btrfs_trans_handle *trans,
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
- set_extent_dirty(info->pinned_extents,
+ set_extent_dirty_nofail(info->pinned_extents,
bytenr, bytenr + num_bytes - 1,
- GFP_NOFS | __GFP_NOFAIL);
+ GFP_NOFS);
}
btrfs_put_block_group(cache);
total -= num_bytes;
@@ -3872,8 +3872,8 @@ static int pin_down_extent(struct btrfs_root *root,
spin_unlock(&cache->lock);
spin_unlock(&cache->space_info->lock);
- set_extent_dirty(root->fs_info->pinned_extents, bytenr,
- bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
+ set_extent_dirty_nofail(root->fs_info->pinned_extents, bytenr,
+ bytenr + num_bytes - 1, GFP_NOFS);
return 0;
}
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -940,6 +940,25 @@ int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
NULL, mask);
}
+/*
+ * NOTE: no new callers of this function should be implemented!
+ * All memory allocations should be failable whenever possible.
+ */
+int set_extent_dirty_nofail(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask)
+{
+ int ret;
+
+ for (;;) {
+ ret = set_extent_dirty(tree, start, end, mask);
+ if (ret != -ENOMEM)
+ return ret;
+ WARN_ONCE(1, "Out of memory, no fallback implemented "
+ "(flags=0x%x)\n",
+ mask);
+ }
+}
+
int set_extent_bits(struct extent_io_tree *tree, u64 start, u64 end,
int bits, gfp_t mask)
{
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -197,6 +197,8 @@ int set_extent_new(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask);
int set_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask);
+int set_extent_dirty_nofail(struct extent_io_tree *tree, u64 start, u64 end,
+ gfp_t mask);
int clear_extent_dirty(struct extent_io_tree *tree, u64 start, u64 end,
gfp_t mask);
int clear_extent_ordered(struct extent_io_tree *tree, u64 start, u64 end,
--
