[PATCH] NFS: Fix potential oops in nfs_inode_remove_request()
From: Benjamin Coddington <hidden>
Date: 2023-10-11 14:44:20
Subsystem:
filesystems (vfs and infrastructure), nfs, sunrpc, and lockd clients, the rest · Maintainers:
Alexander Viro, Christian Brauner, Trond Myklebust, Anna Schumaker, Linus Torvalds
From: Scott Mayhew <redacted>
Once a folio's private data has been cleared, it's possible for another
process to clear the folio->mapping (e.g. via invalidate_complete_folio2
or evict_mapping_folio), so it wouldn't be safe to call
nfs_page_to_inode() after that.
Fixes: 0c493b5cf16e ("NFS: Convert buffered writes to use folios")
Signed-off-by: Scott Mayhew <redacted>
Reviewed-by: Benjamin Coddington <redacted>
Tested-by: Benjamin Coddington <redacted>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
---
fs/nfs/write.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 7720b5e43014..9d82d50ce0b1 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c@@ -788,6 +788,8 @@ static void nfs_inode_add_request(struct nfs_page *req) */ static void nfs_inode_remove_request(struct nfs_page *req) { + struct nfs_inode *nfsi = NFS_I(nfs_page_to_inode(req)); + if (nfs_page_group_sync_on_bit(req, PG_REMOVE)) { struct folio *folio = nfs_page_to_folio(req->wb_head); struct address_space *mapping = folio_file_mapping(folio);
@@ -802,7 +804,7 @@ static void nfs_inode_remove_request(struct nfs_page *req) } if (test_and_clear_bit(PG_INODE_REF, &req->wb_flags)) { - atomic_long_dec(&NFS_I(nfs_page_to_inode(req))->nrequests); + atomic_long_dec(&nfsi->nrequests); nfs_release_request(req); } }
--
2.41.0