There is an inherent race where a symlink file may have been overriden (by a different client) between lookup and readlink, resulting in a spurious EIO error returned to userspace. Fix this by propagating back ESTALE errors such that the vfs will retry the lookup/get_link (similar to nfs4_file_open) at least once. Cc: Dan Aloni <dan.aloni@xxxxxxxxxxxx> Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx> --- Note that with this change the vfs should retry once for ESTALE errors. However with an artificial reproducer of high frequency symlink overrides, nothing prevents the retry to also encounter ESTALE, propagating the error back to userspace. The man pages for openat/readlinkat do not list an ESTALE errno. An alternative attempt (implemented by Dan) was a local retry loop in nfs_get_link(), if this is an applicable approach, Dan can share his patch instead. fs/nfs/symlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c index 0e27a2e4e68b..13818129d268 100644 --- a/fs/nfs/symlink.c +++ b/fs/nfs/symlink.c @@ -41,7 +41,7 @@ static int nfs_symlink_filler(struct file *file, struct folio *folio) error: folio_set_error(folio); folio_unlock(folio); - return -EIO; + return error; } static const char *nfs_get_link(struct dentry *dentry, -- 2.40.1
