From: Dan Carpenter <dan.carpenter@oracle.com>
To: josef@toxicpanda.com
Cc: linux-btrfs@vger.kernel.org
Subject: [bug report] btrfs: make can_nocow_extent nowait compatible
Date: Fri, 23 Sep 2022 17:55:20 +0300 [thread overview]
Message-ID: <Yy3I2J2MxTZQQNjs@kili> (raw)
Hello Josef Bacik,
The patch 9ec9594f6de7: "btrfs: make can_nocow_extent nowait
compatible" from Sep 12, 2022, leads to the following Smatch static
checker warning:
fs/btrfs/extent-tree.c:2225 check_delayed_ref()
warn: refcount leak 'cur_trans->use_count.refs.counter': lines='2225'
fs/btrfs/extent-tree.c
2193 static noinline int check_delayed_ref(struct btrfs_root *root,
2194 struct btrfs_path *path,
2195 u64 objectid, u64 offset, u64 bytenr)
2196 {
2197 struct btrfs_delayed_ref_head *head;
2198 struct btrfs_delayed_ref_node *ref;
2199 struct btrfs_delayed_data_ref *data_ref;
2200 struct btrfs_delayed_ref_root *delayed_refs;
2201 struct btrfs_transaction *cur_trans;
2202 struct rb_node *node;
2203 int ret = 0;
2204
2205 spin_lock(&root->fs_info->trans_lock);
2206 cur_trans = root->fs_info->running_transaction;
2207 if (cur_trans)
2208 refcount_inc(&cur_trans->use_count);
2209 spin_unlock(&root->fs_info->trans_lock);
2210 if (!cur_trans)
2211 return 0;
2212
2213 delayed_refs = &cur_trans->delayed_refs;
2214 spin_lock(&delayed_refs->lock);
2215 head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2216 if (!head) {
2217 spin_unlock(&delayed_refs->lock);
2218 btrfs_put_transaction(cur_trans);
2219 return 0;
2220 }
2221
2222 if (!mutex_trylock(&head->mutex)) {
2223 if (path->nowait) {
2224 spin_unlock(&delayed_refs->lock);
--> 2225 return -EAGAIN;
Call btrfs_put_transaction(cur_trans); before returning?
2226 }
2227
2228 refcount_inc(&head->refs);
2229 spin_unlock(&delayed_refs->lock);
2230
2231 btrfs_release_path(path);
2232
2233 /*
2234 * Mutex was contended, block until it's released and let
2235 * caller try again
2236 */
2237 mutex_lock(&head->mutex);
2238 mutex_unlock(&head->mutex);
2239 btrfs_put_delayed_ref_head(head);
2240 btrfs_put_transaction(cur_trans);
2241 return -EAGAIN;
2242 }
2243 spin_unlock(&delayed_refs->lock);
2244
2245 spin_lock(&head->lock);
2246 /*
2247 * XXX: We should replace this with a proper search function in the
2248 * future.
2249 */
2250 for (node = rb_first_cached(&head->ref_tree); node;
2251 node = rb_next(node)) {
2252 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2253 /* If it's a shared ref we know a cross reference exists */
2254 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2255 ret = 1;
2256 break;
2257 }
2258
2259 data_ref = btrfs_delayed_node_to_data_ref(ref);
2260
2261 /*
2262 * If our ref doesn't match the one we're currently looking at
2263 * then we have a cross reference.
2264 */
2265 if (data_ref->root != root->root_key.objectid ||
2266 data_ref->objectid != objectid ||
2267 data_ref->offset != offset) {
2268 ret = 1;
2269 break;
2270 }
2271 }
2272 spin_unlock(&head->lock);
2273 mutex_unlock(&head->mutex);
2274 btrfs_put_transaction(cur_trans);
2275 return ret;
2276 }
regards,
dan carpenter
next reply other threads:[~2022-09-23 14:55 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 14:55 Dan Carpenter [this message]
2022-09-23 15:22 ` [bug report] btrfs: make can_nocow_extent nowait compatible Josef Bacik
2022-09-29 15:11 ` David Sterba
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Yy3I2J2MxTZQQNjs@kili \
--to=dan.carpenter@oracle.com \
--cc=josef@toxicpanda.com \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).