bcachefs: fix disk reservation accounting in bch2_folio_reservation_get()

Kent Overstreet · Kent Overstreet · commit 81e0b6c7c1f7 · 2024-10-18T00:49:48.000-04:00
bch2_disk_reservation_put() zeroes out the reservation - oops.

This fixes a disk reservation leak when getting a quota reservation
returned an error.

Signed-off-by: Kent Overstreet &lt;kent.overstreet@linux.dev&gt;
diff --git a/fs/bcachefs/fs-io-pagecache.c b/fs/bcachefs/fs-io-pagecache.c
@@ -431,9 +431,9 @@ int bch2_folio_reservation_get(struct bch_fs *c,
 		ret = bch2_quota_reservation_add(c, inode, &res->quota, quota_sectors, true);
 		if (unlikely(ret)) {
 			struct disk_reservation tmp = { .sectors = disk_sectors };
+			res->disk.sectors -= disk_sectors;
 
 			bch2_disk_reservation_put(c, &tmp);
-			res->disk.sectors -= disk_sectors;
 			return ret;
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -431,9 +431,9 @@ int bch2_folio_reservation_get(struct bch_fs *c,`
`431`	`431`	`ret = bch2_quota_reservation_add(c, inode, &res->quota, quota_sectors, true);`
`432`	`432`	`if (unlikely(ret)) {`
`433`	`433`	`struct disk_reservation tmp = { .sectors = disk_sectors };`
	`434`	`+ res->disk.sectors -= disk_sectors;`
`434`	`435`
`435`	`436`	`bch2_disk_reservation_put(c, &tmp);`
`436`		`- res->disk.sectors -= disk_sectors;`
`437`	`437`	`return ret;`
`438`	`438`	`}`
`439`	`439`	`}`