[PATCH 11/29] vfs: trylock inode->i_rwsem in iterate_dir() to support nowait
From: Hao Xu <hidden>
Date: 2023-08-25 14:01:20
Also in:
bpf, io-uring, linux-block, linux-btrfs, linux-cifs, linux-ext4, linux-f2fs-devel, linux-fsdevel, linux-mm, linux-nfs, linux-unionfs, linux-xfs, lkml, netdev
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Hao Xu <redacted> Trylock inode->i_rwsem in iterate_dir() to support nowait semantics and error out -EAGAIN when there is contention. Signed-off-by: Hao Xu <redacted> --- fs/readdir.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
diff --git a/fs/readdir.c b/fs/readdir.c
index 6469f076ba6e..664ecd9665a1 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c@@ -43,6 +43,8 @@ int iterate_dir(struct file *file, struct dir_context *ctx) struct inode *inode = file_inode(file); bool shared = false; int res = -ENOTDIR; + bool nowait; + if (file->f_op->iterate_shared) shared = true; else if (!file->f_op->iterate)
@@ -52,16 +54,22 @@ int iterate_dir(struct file *file, struct dir_context *ctx) if (res) goto out; - if (shared) - res = down_read_killable(&inode->i_rwsem); - else - res = down_write_killable(&inode->i_rwsem); - if (res) + nowait = ctx->flags & DIR_CONTEXT_F_NOWAIT; + if (nowait) { + res = shared ? down_read_trylock(&inode->i_rwsem) : + down_write_trylock(&inode->i_rwsem); + if (!res) + res = -EAGAIN; + } else { + res = shared ? down_read_killable(&inode->i_rwsem) : + down_write_killable(&inode->i_rwsem); + } + if (res < 0) goto out; res = -ENOENT; if (!IS_DEADDIR(inode)) { - res = file_accessed(file, ctx->flags & DIR_CONTEXT_F_NOWAIT); + res = file_accessed(file, nowait); if (res == -EAGAIN) goto out_unlock;
--
2.25.1