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Subject[PATCH v2 13/35] ovl: add ovl_read_iter()
Date
Implement stacked reading.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
fs/overlayfs/file.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index db8778e7c37a..bbc40a14acf8 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -9,6 +9,7 @@
#include <linux/cred.h>
#include <linux/file.h>
#include <linux/xattr.h>
+#include <linux/uio.h>
#include "overlayfs.h"

static struct file *ovl_open_realfile(const struct file *file)
@@ -129,8 +130,74 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
i_size_read(realinode));
}

+static void ovl_file_accessed(struct file *file)
+{
+ struct inode *inode, *upperinode;
+
+ if (file->f_flags & O_NOATIME)
+ return;
+
+ inode = file_inode(file);
+ upperinode = ovl_inode_upper(inode);
+
+ if (!upperinode)
+ return;
+
+ if ((!timespec_equal(&inode->i_mtime, &upperinode->i_mtime) ||
+ !timespec_equal(&inode->i_ctime, &upperinode->i_ctime))) {
+ inode->i_mtime = upperinode->i_mtime;
+ inode->i_ctime = upperinode->i_ctime;
+ }
+
+ touch_atime(&file->f_path);
+}
+
+static rwf_t ovl_iocb_to_rwf(struct kiocb *iocb)
+{
+ int ifl = iocb->ki_flags;
+ rwf_t flags = 0;
+
+ if (ifl & IOCB_NOWAIT)
+ flags |= RWF_NOWAIT;
+ if (ifl & IOCB_HIPRI)
+ flags |= RWF_HIPRI;
+ if (ifl & IOCB_DSYNC)
+ flags |= RWF_DSYNC;
+ if (ifl & IOCB_SYNC)
+ flags |= RWF_SYNC;
+
+ return flags;
+}
+
+static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
+{
+ struct file *file = iocb->ki_filp;
+ struct fd real;
+ const struct cred *old_cred;
+ ssize_t ret;
+
+ if (!iov_iter_count(iter))
+ return 0;
+
+ ret = ovl_real_fdget(file, &real);
+ if (ret)
+ return ret;
+
+ old_cred = ovl_override_creds(file_inode(file)->i_sb);
+ ret = vfs_iter_read(real.file, iter, &iocb->ki_pos,
+ ovl_iocb_to_rwf(iocb));
+ revert_creds(old_cred);
+
+ ovl_file_accessed(file);
+
+ fdput(real);
+
+ return ret;
+}
+
const struct file_operations ovl_file_operations = {
.open = ovl_open,
.release = ovl_release,
.llseek = ovl_llseek,
+ .read_iter = ovl_read_iter,
};
--
2.14.3
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