[PATCH 08/39] experimental: convert fs/overlayfs/file.c to CLASS(...)

viro
2024-07-30T05:14:54Z

From: Al Viro <viro@zeniv.linux.org.uk>

There are four places where we end up adding an extra scope
covering just the range from constructor to destructor;
not sure if that's the best way to handle that.

The functions in question are ovl_write_iter(), ovl_splice_write(),
ovl_fadvise() and ovl_copyfile().

This is very likely *NOT* the final form of that thing - it
needs to be discussed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/overlayfs/file.c | 72 ++++++++++++++++++---------------------------
1 file changed, 29 insertions(+), 43 deletions(-)

diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index 4b9e145bc7b8..a2911c632137 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -132,6 +132,8 @@ static struct fderr ovl_real_fdget(const struct file *file)
return ovl_real_fdget_meta(file, false);
}

+DEFINE_CLASS(fd_real, struct fderr, fdput(_T), ovl_real_fdget(file), struct file *file)
+
static int ovl_open(struct inode *inode, struct file *file)
{
struct dentry *dentry = file_dentry(file);
@@ -174,7 +176,6 @@ static int ovl_release(struct inode *inode, struct file *file)
static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file_inode(file);
- struct fderr real;
const struct cred *old_cred;
loff_t ret;

@@ -190,7 +191,7 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
return vfs_setpos(file, 0, 0);
}

- real = ovl_real_fdget(file);
+ CLASS(fd_real, real)(file);
if (fd_empty(real))
return fd_error(real);

@@ -211,8 +212,6 @@ static loff_t ovl_llseek(struct file *file, loff_t offset, int whence)
file->f_pos = fd_file(real)->f_pos;
ovl_inode_unlock(inode);

- fdput(real);
-
return ret;
}

@@ -253,8 +252,6 @@ static void ovl_file_accessed(struct file *file)
static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
- struct fderr real;
- ssize_t ret;
struct backing_file_ctx ctx = {
.cred = ovl_creds(file_inode(file)->i_sb),
.user_file = file,
@@ -264,22 +261,18 @@ static ssize_t ovl_read_iter(struct kiocb *iocb, struct iov_iter *iter)
if (!iov_iter_count(iter))
return 0;

- real = ovl_real_fdget(file);
+ CLASS(fd_real, real)(file);
if (fd_empty(real))
return fd_error(real);

- ret = backing_file_read_iter(fd_file(real), iter, iocb, iocb->ki_flags,
- &ctx);
- fdput(real);
-
- return ret;
+ return backing_file_read_iter(fd_file(real), iter, iocb, iocb->ki_flags,
+ &ctx);
}

static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
- struct fderr real;
ssize_t ret;
int ifl = iocb->ki_flags;
struct backing_file_ctx ctx = {
@@ -295,7 +288,9 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
/* Update mode */
ovl_copyattr(inode);

- real = ovl_real_fdget(file);
+ {
+
+ CLASS(fd_real, real)(file);
if (fd_empty(real)) {
ret = fd_error(real);
goto out_unlock;
@@ -310,7 +305,8 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter)
*/
ifl &= ~IOCB_DIO_CALLER_COMP;
ret = backing_file_write_iter(fd_file(real), iter, iocb, ifl, &ctx);
- fdput(real);
+
+ }

out_unlock:
inode_unlock(inode);
@@ -322,22 +318,18 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
- struct fderr real;
- ssize_t ret;
+ CLASS(fd_real, real)(in);
struct backing_file_ctx ctx = {
.cred = ovl_creds(file_inode(in)->i_sb),
.user_file = in,
.accessed = ovl_file_accessed,
};

- real = ovl_real_fdget(in);
if (fd_empty(real))
return fd_error(real);

- ret = backing_file_splice_read(fd_file(real), ppos, pipe, len, flags, &ctx);
- fdput(real);
-
- return ret;
+ return backing_file_splice_read(fd_file(real), ppos, pipe, len, flags,
+ &ctx);
}

/*
@@ -351,7 +343,6 @@ static ssize_t ovl_splice_read(struct file *in, loff_t *ppos,
static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
loff_t *ppos, size_t len, unsigned int flags)
{
- struct fderr real;
struct inode *inode = file_inode(out);
ssize_t ret;
struct backing_file_ctx ctx = {
@@ -364,15 +355,17 @@ static ssize_t ovl_splice_write(struct pipe_inode_info *pipe, struct file *out,
/* Update mode */
ovl_copyattr(inode);

- real = ovl_real_fdget(out);
+ {
+
+ CLASS(fd_real, real)(out);
if (fd_empty(real)) {
ret = fd_error(real);
goto out_unlock;
}

ret = backing_file_splice_write(pipe, fd_file(real), ppos, len, flags, &ctx);
- fdput(real);

+ }
out_unlock:
inode_unlock(inode);

@@ -420,7 +413,6 @@ static int ovl_mmap(struct file *file, struct vm_area_struct *vma)
static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
{
struct inode *inode = file_inode(file);
- struct fderr real;
const struct cred *old_cred;
int ret;

@@ -430,7 +422,9 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
ret = file_remove_privs(file);
if (ret)
goto out_unlock;
- real = ovl_real_fdget(file);
+ {
+
+ CLASS(fd_real, real)(file);
if (fd_empty(real)) {
ret = fd_error(real);
goto out_unlock;
@@ -443,8 +437,7 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len
/* Update size */
ovl_file_modified(file);

- fdput(real);
-
+ }
out_unlock:
inode_unlock(inode);

@@ -453,11 +446,10 @@ static long ovl_fallocate(struct file *file, int mode, loff_t offset, loff_t len

static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
{
- struct fderr real;
+ CLASS(fd_real, real)(file);
const struct cred *old_cred;
int ret;

- real = ovl_real_fdget(file);
if (fd_empty(real))
return fd_error(real);

@@ -465,8 +457,6 @@ static int ovl_fadvise(struct file *file, loff_t offset, loff_t len, int advice)
ret = vfs_fadvise(fd_file(real), offset, len, advice);
revert_creds(old_cred);

- fdput(real);
-
return ret;
}

@@ -481,7 +471,6 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
loff_t len, unsigned int flags, enum ovl_copyop op)
{
struct inode *inode_out = file_inode(file_out);
- struct fderr real_in, real_out;
const struct cred *old_cred;
loff_t ret;

@@ -494,15 +483,16 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
goto out_unlock;
}

- real_out = ovl_real_fdget(file_out);
+ {
+
+ CLASS(fd_real, real_out)(file_out);
if (fd_empty(real_out)) {
ret = fd_error(real_out);
goto out_unlock;
}

- real_in = ovl_real_fdget(file_in);
+ CLASS(fd_real, real_in)(file_in);
if (fd_empty(real_in)) {
- fdput(real_out);
ret = fd_error(real_in);
goto out_unlock;
}
@@ -530,8 +520,7 @@ static loff_t ovl_copyfile(struct file *file_in, loff_t pos_in,
/* Update size */
ovl_file_modified(file_out);

- fdput(real_in);
- fdput(real_out);
+ }

out_unlock:
inode_unlock(inode_out);
@@ -576,11 +565,10 @@ static loff_t ovl_remap_file_range(struct file *file_in, loff_t pos_in,

static int ovl_flush(struct file *file, fl_owner_t id)
{
- struct fderr real;
+ CLASS(fd_real, real)(file);
const struct cred *old_cred;
int err = 0;

- real = ovl_real_fdget(file);
if (fd_empty(real))
return fd_error(real);

@@ -589,8 +577,6 @@ static int ovl_flush(struct file *file, fl_owner_t id)
err = fd_file(real)->f_op->flush(fd_file(real), id);
revert_creds(old_cred);
}
- fdput(real);
-
return err;
}

--
2.39.2