On Tue, May 08, 2018 at 05:14:42PM +0300, Amir Goldstein wrote:
> On Tue, May 8, 2018 at 3:50 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> >
> [...]
> >
> > Ok, here is the updated patch. I have not defined quivalent of
> > ovl_real_meta_file() as there are no users.
> >
> >
> > Subject: ovl: Open file with data except for the case of fsync
> >
> > ovl_open() should open file which contains data and not open metacopy
> > inode. With the introduction of metacopy inodes, with current implementaion
> > we will end up opening metacopy inode as well.
> >
> > But there can be certain circumstances like ovl_fsync() where we
> > want to allow opening a metacopy inode instead.
> >
> > Hence, change ovl_open_realfile() and ovl_open_real() and add extra
> > parameter which specifies whether to allow opening metacopy inode or not.
> > If this parameter is false, we look for data inode and open that.
> >
> > This should allow covering both the cases.
> >
> > Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
>
> Nice! much shorter. You can add
> Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
>
> BTW, I have never given that much thought, but I see that you
> added Reviewed-by before Signed-off-by in some of the patches
> and after SOB in other patches.
> Of course it doesn't really matter and there isn't a single convention
> in the kernel, but the way I always thought about it is:
> You sign-off at the bottom on the complete work including all the tags
> may have added.
I was thinking about it and looked at some of the kernel commits and
there seem to be a mix. There does not seem to be a fixed convention
on the order of these tags.
My take away was that they seem to be ordered FIFO order. So I
do my Signed-off-by:, then you have your Reviewed-by and when
Miklos merges these, he will put his sign-off-by.
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
If you do not disagree with above, I will make order of Reviewed-by
consistent in whole series and push again metacopy-next branch.
Vivek
>
> Feel free to ignore this OCD comment ;-)
>
> > ---
> > fs/overlayfs/file.c | 40 +++++++++++++++++++++++++++++++---------
> > 1 file changed, 31 insertions(+), 9 deletions(-)
> >
> > Index: rhvgoyal-linux/fs/overlayfs/file.c
> > ===================================================================
> > --- rhvgoyal-linux.orig/fs/overlayfs/file.c 2018-05-07 16:55:02.562350785 -0400
> > +++ rhvgoyal-linux/fs/overlayfs/file.c 2018-05-08 08:46:49.994350785 -0400
> > @@ -14,22 +14,32 @@
> > #include <linux/uio.h>
> > #include "overlayfs.h"
> >
> > -static struct file *ovl_open_realfile(const struct file *file)
> > +static struct file *ovl_open_realfile(const struct file *file,
> > + bool allow_metacopy)
> > {
> > struct inode *inode = file_inode(file);
> > struct inode *upperinode = ovl_inode_upper(inode);
> > - struct inode *realinode = upperinode ?: ovl_inode_lower(inode);
> > + struct inode *realinode;
> > struct file *realfile;
> > + bool upperopen = false;
> > const struct cred *old_cred;
> >
> > + if (upperinode && (allow_metacopy || ovl_has_upperdata(inode))) {
> > + realinode = upperinode;
> > + upperopen = true;
> > + } else {
> > + realinode = allow_metacopy ? ovl_inode_lower(inode) :
> > + ovl_inode_lowerdata(inode);
> > + }
> > old_cred = ovl_override_creds(inode->i_sb);
> > realfile = path_open(&file->f_path, file->f_flags | O_NOATIME,
> > realinode, current_cred(), false);
> > revert_creds(old_cred);
> >
> > pr_debug("open(%p[%pD2/%c], 0%o) -> (%p, 0%o)\n",
> > - file, file, upperinode ? 'u' : 'l', file->f_flags,
> > - realfile, IS_ERR(realfile) ? 0 : realfile->f_flags);
> > + file, file, upperopen ? 'u' : 'l',
> > + file->f_flags, realfile,
> > + IS_ERR(realfile) ? 0 : realfile->f_flags);
> >
> > return realfile;
> > }
> > @@ -72,17 +82,24 @@ static int ovl_change_flags(struct file
> > return 0;
> > }
> >
> > -static int ovl_real_fdget(const struct file *file, struct fd *real)
> > +static int _ovl_real_fdget(const struct file *file, struct fd *real,
> > + bool allow_metacopy)
> > {
> > struct inode *inode = file_inode(file);
> > + struct inode *realinode;
> >
> > real->flags = 0;
> > real->file = file->private_data;
> >
> > + if (allow_metacopy)
> > + realinode = ovl_inode_real(inode);
> > + else
> > + realinode = ovl_inode_realdata(inode);
> > +
> > /* Has it been copied up since we'd opened it? */
> > - if (unlikely(file_inode(real->file) != ovl_inode_real(inode))) {
> > + if (unlikely(file_inode(real->file) != realinode)) {
> > real->flags = FDPUT_FPUT;
> > - real->file = ovl_open_realfile(file);
> > + real->file = ovl_open_realfile(file, allow_metacopy);
> >
> > return PTR_ERR_OR_ZERO(real->file);
> > }
> > @@ -94,6 +111,11 @@ static int ovl_real_fdget(const struct f
> > return 0;
> > }
> >
> > +static int ovl_real_fdget(const struct file *file, struct fd *real)
> > +{
> > + return _ovl_real_fdget(file, real, false);
> > +}
> > +
> > static int ovl_open(struct inode *inode, struct file *file)
> > {
> > struct dentry *dentry = file_dentry(file);
> > @@ -107,7 +129,7 @@ static int ovl_open(struct inode *inode,
> > /* No longer need these flags, so don't pass them on to underlying fs */
> > file->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
> >
> > - realfile = ovl_open_realfile(file);
> > + realfile = ovl_open_realfile(file, false);
> > if (IS_ERR(realfile))
> > return PTR_ERR(realfile);
> >
> > @@ -244,7 +266,7 @@ static int ovl_fsync(struct file *file,
> > const struct cred *old_cred;
> > int ret;
> >
> > - ret = ovl_real_fdget(file, &real);
> > + ret = _ovl_real_fdget(file, &real, !datasync);
> > if (ret)
> > return ret;
> >
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