Btrfs: use kmalloc instead of stack for backref_ctx
Make sure to never get in trouble due to the backref_ctx
which was on the stack before.
Commit is a result of Arne's review.
Signed-off-by: Alexander Block <ablock84@googlemail.com>
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index a25be0c..3671112 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -1149,7 +1149,7 @@
u64 extent_item_pos;
struct btrfs_file_extent_item *fi;
struct extent_buffer *eb = path->nodes[0];
- struct backref_ctx backref_ctx;
+ struct backref_ctx *backref_ctx = NULL;
struct clone_root *cur_clone_root;
struct btrfs_key found_key;
struct btrfs_path *tmp_path;
@@ -1159,6 +1159,12 @@
if (!tmp_path)
return -ENOMEM;
+ backref_ctx = kmalloc(sizeof(*backref_ctx), GFP_NOFS);
+ if (!backref_ctx) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
if (data_offset >= ino_size) {
/*
* There may be extents that lie behind the file's size.
@@ -1206,12 +1212,12 @@
cur_clone_root->found_refs = 0;
}
- backref_ctx.sctx = sctx;
- backref_ctx.found = 0;
- backref_ctx.cur_objectid = ino;
- backref_ctx.cur_offset = data_offset;
- backref_ctx.found_itself = 0;
- backref_ctx.extent_len = num_bytes;
+ backref_ctx->sctx = sctx;
+ backref_ctx->found = 0;
+ backref_ctx->cur_objectid = ino;
+ backref_ctx->cur_offset = data_offset;
+ backref_ctx->found_itself = 0;
+ backref_ctx->extent_len = num_bytes;
/*
* The last extent of a file may be too large due to page alignment.
@@ -1219,7 +1225,7 @@
* __iterate_backrefs work.
*/
if (data_offset + num_bytes >= ino_size)
- backref_ctx.extent_len = ino_size - data_offset;
+ backref_ctx->extent_len = ino_size - data_offset;
/*
* Now collect all backrefs.
@@ -1227,11 +1233,11 @@
extent_item_pos = logical - found_key.objectid;
ret = iterate_extent_inodes(sctx->send_root->fs_info,
found_key.objectid, extent_item_pos, 1,
- __iterate_backrefs, &backref_ctx);
+ __iterate_backrefs, backref_ctx);
if (ret < 0)
goto out;
- if (!backref_ctx.found_itself) {
+ if (!backref_ctx->found_itself) {
/* found a bug in backref code? */
ret = -EIO;
printk(KERN_ERR "btrfs: ERROR did not find backref in "
@@ -1246,7 +1252,7 @@
"num_bytes=%llu, logical=%llu\n",
data_offset, ino, num_bytes, logical);
- if (!backref_ctx.found)
+ if (!backref_ctx->found)
verbose_printk("btrfs: no clones found\n");
cur_clone_root = NULL;
@@ -1271,6 +1277,7 @@
out:
btrfs_free_path(tmp_path);
+ kfree(backref_ctx);
return ret;
}