| Message ID | 20241003234808.GC147780@ZenIV (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | introduce struct fderr, convert overlayfs uses to that | expand |
On Fri, Oct 04, 2024 at 12:48:08AM GMT, Al Viro wrote: > There are four places where we end up adding an extra scope > covering just the range from constructor to destructor; I don't think this is something to worry about. While there are cases where the width of the scope might make a meaningful difference I doubt it does here. > 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(). > > I still don't like the way we have to deal with the scopes, but... > use of guard() for inode_lock()/inode_unlock() is a gutter too deep, > as far as I'm concerned. > > 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 c711fa5d802f..a0ab981b13d9 100644 > --- a/fs/overlayfs/file.c > +++ b/fs/overlayfs/file.c > @@ -131,6 +131,8 @@ 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); > @@ -173,7 +175,6 @@ 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; > > @@ -189,7 +190,7 @@ 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_err(real); > > @@ -210,8 +211,6 @@ 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; > } > > @@ -252,8 +251,6 @@ 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, > @@ -263,22 +260,18 @@ 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_err(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 = { > @@ -294,7 +287,9 @@ 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_err(real); > goto out_unlock; > @@ -309,7 +304,8 @@ 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); > @@ -321,22 +317,18 @@ 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_err(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); > } > > /* > @@ -350,7 +342,6 @@ 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 = { > @@ -363,15 +354,17 @@ 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_err(real); > goto out_unlock; > } > > ret = backing_file_splice_write(pipe, fd_file(real), ppos, len, flags, &ctx); > - fdput(real); > > + } > out_unlock: > inode_unlock(inode); > > @@ -419,7 +412,6 @@ 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; > > @@ -429,7 +421,9 @@ 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_err(real); > goto out_unlock; > @@ -442,8 +436,7 @@ 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); > > @@ -452,11 +445,10 @@ 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_err(real); > > @@ -464,8 +456,6 @@ 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; > } > > @@ -480,7 +470,6 @@ 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; > > @@ -493,15 +482,16 @@ 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_err(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_err(real_in); > goto out_unlock; > } > @@ -529,8 +519,7 @@ 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); > @@ -575,11 +564,10 @@ 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_err(real); > > @@ -588,8 +576,6 @@ 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; > } > > -- > 2.39.5 >
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index c711fa5d802f..a0ab981b13d9 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -131,6 +131,8 @@ 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); @@ -173,7 +175,6 @@ 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; @@ -189,7 +190,7 @@ 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_err(real); @@ -210,8 +211,6 @@ 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; } @@ -252,8 +251,6 @@ 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, @@ -263,22 +260,18 @@ 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_err(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 = { @@ -294,7 +287,9 @@ 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_err(real); goto out_unlock; @@ -309,7 +304,8 @@ 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); @@ -321,22 +317,18 @@ 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_err(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); } /* @@ -350,7 +342,6 @@ 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 = { @@ -363,15 +354,17 @@ 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_err(real); goto out_unlock; } ret = backing_file_splice_write(pipe, fd_file(real), ppos, len, flags, &ctx); - fdput(real); + } out_unlock: inode_unlock(inode); @@ -419,7 +412,6 @@ 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; @@ -429,7 +421,9 @@ 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_err(real); goto out_unlock; @@ -442,8 +436,7 @@ 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); @@ -452,11 +445,10 @@ 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_err(real); @@ -464,8 +456,6 @@ 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; } @@ -480,7 +470,6 @@ 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; @@ -493,15 +482,16 @@ 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_err(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_err(real_in); goto out_unlock; } @@ -529,8 +519,7 @@ 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); @@ -575,11 +564,10 @@ 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_err(real); @@ -588,8 +576,6 @@ 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; }
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(). I still don't like the way we have to deal with the scopes, but... use of guard() for inode_lock()/inode_unlock() is a gutter too deep, as far as I'm concerned. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- fs/overlayfs/file.c | 72 ++++++++++++++++++--------------------------- 1 file changed, 29 insertions(+), 43 deletions(-)