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| author | Jingbo Xu <jefflexu@linux.alibaba.com> | 2022-11-14 20:19:43 +0800 |
|---|---|---|
| committer | Gao Xiang <hsiangkao@linux.alibaba.com> | 2022-11-14 23:48:38 +0800 |
| commit | 37020bbb71d911431e16c2c940b97cf86ae4f2f6 (patch) | |
| tree | 4d62cb1eda9dd8b6ee2f1059a9746492412c11c4 /fs | |
| parent | 39bfcb8138f6dc3375f23b1e62ccfc7c0d83295d (diff) | |
| download | lwn-37020bbb71d911431e16c2c940b97cf86ae4f2f6.tar.gz lwn-37020bbb71d911431e16c2c940b97cf86ae4f2f6.zip | |
erofs: fix missing xas_retry() in fscache mode
The xarray iteration only holds the RCU read lock and thus may encounter
XA_RETRY_ENTRY if there's process modifying the xarray concurrently.
This will cause oops when referring to the invalid entry.
Fix this by adding the missing xas_retry(), which will make the
iteration wind back to the root node if XA_RETRY_ENTRY is encountered.
Fixes: d435d53228dd ("erofs: change to use asynchronous io for fscache readpage/readahead")
Suggested-by: David Howells <dhowells@redhat.com>
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Jia Zhu <zhujia.zj@bytedance.com>
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20221114121943.29987-1-jefflexu@linux.alibaba.com
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/erofs/fscache.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c index 6eaf4a4ab95c..af5ed6b9c54d 100644 --- a/fs/erofs/fscache.c +++ b/fs/erofs/fscache.c @@ -75,11 +75,15 @@ static void erofs_fscache_rreq_unlock_folios(struct netfs_io_request *rreq) rcu_read_lock(); xas_for_each(&xas, folio, last_page) { - unsigned int pgpos = - (folio_index(folio) - start_page) * PAGE_SIZE; - unsigned int pgend = pgpos + folio_size(folio); + unsigned int pgpos, pgend; bool pg_failed = false; + if (xas_retry(&xas, folio)) + continue; + + pgpos = (folio_index(folio) - start_page) * PAGE_SIZE; + pgend = pgpos + folio_size(folio); + for (;;) { if (!subreq) { pg_failed = true; |