Since down_read can block, use the _trylock variant if NOWAIT variant
has been requested.
(can probably do a little bit better style-wise)
Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
---
fs/kernfs/dir.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 45b6919903e6..5a5b3e7881bf 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -1824,7 +1824,12 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
return 0;
root = kernfs_root(parent);
- down_read(&root->kernfs_rwsem);
+ if (ctx->flags & DIR_CONTEXT_F_NOWAIT) {
+ if (!down_read_trylock(&root->kernfs_rwsem))
+ return -EAGAIN;
+ } else {
+ down_read(&root->kernfs_rwsem);
+ }
if (kernfs_ns_enabled(parent))
ns = kernfs_info(dentry->d_sb)->ns;
@@ -1845,6 +1850,12 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
if (!dir_emit(ctx, name, len, ino, type))
return 0;
down_read(&root->kernfs_rwsem);
+ if (ctx->flags & DIR_CONTEXT_F_NOWAIT) {
+ if (!down_read_trylock(&root->kernfs_rwsem))
+ return 0;
+ } else {
+ down_read(&root->kernfs_rwsem);
+ }
}
up_read(&root->kernfs_rwsem);
file->private_data = NULL;
@@ -1852,7 +1863,14 @@ static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
return 0;
}
+static int kernfs_fop_dir_open(struct inode *inode, struct file *file)
+{
+ file->f_mode |= FMODE_NOWAIT;
+ return 0;
+}
+
const struct file_operations kernfs_dir_fops = {
+ .open = kernfs_fop_dir_open,
.read = generic_read_dir,
.iterate_shared = kernfs_fop_readdir,
.release = kernfs_dir_fop_release,
--
2.39.2
