[PATCH v3 1/3] fs: add parameter use_fpos to iterate_dir function

Stefan Roesch
2021-11-25T23:28:01Z

This adds the use_fpos parameter to the iterate_dir function.
If use_fpos is true it uses the file position in the file
structure (existing behavior). If use_fpos is false, it uses
the pos in the context structure.

This change is required to support getdents in io_uring.

Signed-off-by: Stefan Roesch <shr@fb.com>
---
fs/readdir.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/fs/readdir.c b/fs/readdir.c
index 09e8ed7d4161..e9c197edf73a 100644
--- a/fs/readdir.c
+++ b/fs/readdir.c
@@ -36,8 +36,15 @@
unsafe_copy_to_user(dst, src, len, label); \
} while (0)

-
-int iterate_dir(struct file *file, struct dir_context *ctx)
+/**
+ * do_iterate_dir - iterate over directory
+ * @file : pointer to file struct of directory
+ * @ctx : pointer to directory ctx structure
+ * @use_fpos: true : use file offset
+ * false: use pos in ctx structure
+ */
+static int do_iterate_dir(struct file *file, struct dir_context *ctx,
+ bool use_fpos)
{
struct inode *inode = file_inode(file);
bool shared = false;
@@ -60,12 +67,17 @@ int iterate_dir(struct file *file, struct dir_context *ctx)

res = -ENOENT;
if (!IS_DEADDIR(inode)) {
- ctx->pos = file->f_pos;
+ if (use_fpos)
+ ctx->pos = file->f_pos;
+
if (shared)
res = file->f_op->iterate_shared(file, ctx);
else
res = file->f_op->iterate(file, ctx);
- file->f_pos = ctx->pos;
+
+ if (use_fpos)
+ file->f_pos = ctx->pos;
+
fsnotify_access(file);
file_accessed(file);
}
@@ -76,6 +88,11 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
out:
return res;
}
+
+int iterate_dir(struct file *file, struct dir_context *ctx)
+{
+ return do_iterate_dir(file, ctx, true);
+}
EXPORT_SYMBOL(iterate_dir);

/*
--
2.30.2