diff options
| author | Trond Myklebust <trond.myklebust@hammerspace.com> | 2025-12-31 19:42:31 +0300 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@hammerspace.com> | 2026-01-05 07:03:24 +0300 |
| commit | cce0be6eb4971456b703aaeafd571650d314bcca (patch) | |
| tree | 2d3741ca0b4b4c6e1f538534ac603da5d74834c6 /fs | |
| parent | 857bf9056291a16785ae3be1d291026b2437fc48 (diff) | |
| download | linux-cce0be6eb4971456b703aaeafd571650d314bcca.tar.xz | |
NFS: Fix a deadlock involving nfs_release_folio()
Wang Zhaolong reports a deadlock involving NFSv4.1 state recovery
waiting on kthreadd, which is attempting to reclaim memory by calling
nfs_release_folio(). The latter cannot make progress due to state
recovery being needed.
It seems that the only safe thing to do here is to kick off a writeback
of the folio, without waiting for completion, or else kicking off an
asynchronous commit.
Reported-by: Wang Zhaolong <wangzhaolong@huaweicloud.com>
Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfs/file.c | 3 | ||||
| -rw-r--r-- | fs/nfs/nfstrace.h | 3 | ||||
| -rw-r--r-- | fs/nfs/write.c | 33 |
3 files changed, 38 insertions, 1 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c index d020aab40c64..d1c138a416cf 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -511,7 +511,8 @@ static bool nfs_release_folio(struct folio *folio, gfp_t gfp) if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL || current_is_kswapd() || current_is_kcompactd()) return false; - if (nfs_wb_folio(folio->mapping->host, folio) < 0) + if (nfs_wb_folio_reclaim(folio->mapping->host, folio) < 0 || + folio_test_private(folio)) return false; } return nfs_fscache_release_folio(folio, gfp); diff --git a/fs/nfs/nfstrace.h b/fs/nfs/nfstrace.h index 6ce55e8e6b67..9f9ce4a565ea 100644 --- a/fs/nfs/nfstrace.h +++ b/fs/nfs/nfstrace.h @@ -1062,6 +1062,9 @@ DECLARE_EVENT_CLASS(nfs_folio_event_done, DEFINE_NFS_FOLIO_EVENT(nfs_aop_readpage); DEFINE_NFS_FOLIO_EVENT_DONE(nfs_aop_readpage_done); +DEFINE_NFS_FOLIO_EVENT(nfs_writeback_folio_reclaim); +DEFINE_NFS_FOLIO_EVENT_DONE(nfs_writeback_folio_reclaim_done); + DEFINE_NFS_FOLIO_EVENT(nfs_writeback_folio); DEFINE_NFS_FOLIO_EVENT_DONE(nfs_writeback_folio_done); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 336c510f3750..bf412455e8ed 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -2025,6 +2025,39 @@ int nfs_wb_folio_cancel(struct inode *inode, struct folio *folio) } /** + * nfs_wb_folio_reclaim - Write back all requests on one page + * @inode: pointer to page + * @folio: pointer to folio + * + * Assumes that the folio has been locked by the caller + */ +int nfs_wb_folio_reclaim(struct inode *inode, struct folio *folio) +{ + loff_t range_start = folio_pos(folio); + size_t len = folio_size(folio); + struct writeback_control wbc = { + .sync_mode = WB_SYNC_ALL, + .nr_to_write = 0, + .range_start = range_start, + .range_end = range_start + len - 1, + .for_sync = 1, + }; + int ret; + + if (folio_test_writeback(folio)) + return -EBUSY; + if (folio_clear_dirty_for_io(folio)) { + trace_nfs_writeback_folio_reclaim(inode, range_start, len); + ret = nfs_writepage_locked(folio, &wbc); + trace_nfs_writeback_folio_reclaim_done(inode, range_start, len, + ret); + return ret; + } + nfs_commit_inode(inode, 0); + return 0; +} + +/** * nfs_wb_folio - Write back all requests on one page * @inode: pointer to page * @folio: pointer to folio |