| Message ID | 20181019152905.32418-2-olga.kornievskaia@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | server-side support for "inter" SSC copy | expand |
On Fri, Oct 19, 2018 at 11:28:53AM -0400, Olga Kornievskaia wrote: > From: Anna Schumaker <Anna.Schumaker@Netapp.com> I have some idea we've had some discussion about this before, but if so I've forgotten the conclusion. Could we have more of a changelog?: - isn't there a race condition, or is there something preventing the file size from changing here? - why are we doing this? Does this change the behavior of copy_file_range()? --b. > > Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > --- > fs/read_write.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/read_write.c b/fs/read_write.c > index 39b4a21..c60790f 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1570,6 +1570,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > if (unlikely(ret)) > return ret; > > + if (pos_in >= i_size_read(inode_in)) > + return -EINVAL; > + > if (!(file_in->f_mode & FMODE_READ) || > !(file_out->f_mode & FMODE_WRITE) || > (file_out->f_flags & O_APPEND)) > -- > 1.8.3.1
On Wed, Oct 31, 2018 at 12:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > On Fri, Oct 19, 2018 at 11:28:53AM -0400, Olga Kornievskaia wrote: > > From: Anna Schumaker <Anna.Schumaker@Netapp.com> > > I have some idea we've had some discussion about this before, but if so > I've forgotten the conclusion. Could we have more of a changelog?: > > - isn't there a race condition, or is there something preventing > the file size from changing here? No there is nothing preventing the size from changing. Just like there is nothing that prevents the file from changing if you are doing a traditional copy either. > - why are we doing this? Does this change the behavior of > copy_file_range()? We are doing this because 1. NFS spec and 2. copy_file_range semantics mandate that too. There is a whole different discussion under the client-side patch for this where the plan now is that VFS themselves are interested in making sure they are indeed enforcing the check stated by the documentation of copy_file_range call which states "copying a range beyond the end of the file" is EINVAL. I recall you argued for a "short" read instead of a EINVAL but unless VFS community is convinced to change it it'll be enforced (soon). > > --b. > > > > > Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > > --- > > fs/read_write.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > index 39b4a21..c60790f 100644 > > --- a/fs/read_write.c > > +++ b/fs/read_write.c > > @@ -1570,6 +1570,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > > if (unlikely(ret)) > > return ret; > > > > + if (pos_in >= i_size_read(inode_in)) > > + return -EINVAL; > > + > > if (!(file_in->f_mode & FMODE_READ) || > > !(file_out->f_mode & FMODE_WRITE) || > > (file_out->f_flags & O_APPEND)) > > -- > > 1.8.3.1
On Wed, Oct 31, 2018 at 01:07:11PM -0400, Olga Kornievskaia wrote: > On Wed, Oct 31, 2018 at 12:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > > > On Fri, Oct 19, 2018 at 11:28:53AM -0400, Olga Kornievskaia wrote: > > > From: Anna Schumaker <Anna.Schumaker@Netapp.com> > > > > I have some idea we've had some discussion about this before, but if so > > I've forgotten the conclusion. Could we have more of a changelog?: > > > > - isn't there a race condition, or is there something preventing > > the file size from changing here? > > No there is nothing preventing the size from changing. Just like there > is nothing that prevents the file from changing if you are doing a > traditional copy either. > > > - why are we doing this? Does this change the behavior of > > copy_file_range()? > > We are doing this because 1. NFS spec and 2. copy_file_range semantics > mandate that too. There is a whole different discussion under the > client-side patch for this where the plan now is that VFS themselves > are interested in making sure they are indeed enforcing the check > stated by the documentation of copy_file_range call which states > "copying a range beyond the end of the file" is EINVAL. I recall you > argued for a "short" read instead of a EINVAL but unless VFS community > is convinced to change it it'll be enforced (soon). OK. Let's just make sure the reasoning's mentioned in the changelog, whatever we do. --b. > > --b. > > > > > > > > Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > > > --- > > > fs/read_write.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > > index 39b4a21..c60790f 100644 > > > --- a/fs/read_write.c > > > +++ b/fs/read_write.c > > > @@ -1570,6 +1570,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > > > if (unlikely(ret)) > > > return ret; > > > > > > + if (pos_in >= i_size_read(inode_in)) > > > + return -EINVAL; > > > + > > > if (!(file_in->f_mode & FMODE_READ) || > > > !(file_out->f_mode & FMODE_WRITE) || > > > (file_out->f_flags & O_APPEND)) > > > -- > > > 1.8.3.1
On Wed, Oct 31, 2018 at 1:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > On Wed, Oct 31, 2018 at 01:07:11PM -0400, Olga Kornievskaia wrote: > > On Wed, Oct 31, 2018 at 12:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > > > > > On Fri, Oct 19, 2018 at 11:28:53AM -0400, Olga Kornievskaia wrote: > > > > From: Anna Schumaker <Anna.Schumaker@Netapp.com> > > > > > > I have some idea we've had some discussion about this before, but if so > > > I've forgotten the conclusion. Could we have more of a changelog?: > > > > > > - isn't there a race condition, or is there something preventing > > > the file size from changing here? > > > > No there is nothing preventing the size from changing. Just like there > > is nothing that prevents the file from changing if you are doing a > > traditional copy either. > > > > > - why are we doing this? Does this change the behavior of > > > copy_file_range()? > > > > We are doing this because 1. NFS spec and 2. copy_file_range semantics > > mandate that too. There is a whole different discussion under the > > client-side patch for this where the plan now is that VFS themselves > > are interested in making sure they are indeed enforcing the check > > stated by the documentation of copy_file_range call which states > > "copying a range beyond the end of the file" is EINVAL. I recall you > > argued for a "short" read instead of a EINVAL but unless VFS community > > is convinced to change it it'll be enforced (soon). > > OK. Let's just make sure the reasoning's mentioned in the changelog, > whatever we do. By the changelog, you mean the commit message? > > --b. > > > > --b. > > > > > > > > > > > Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> > > > > --- > > > > fs/read_write.c | 3 +++ > > > > 1 file changed, 3 insertions(+) > > > > > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > > > index 39b4a21..c60790f 100644 > > > > --- a/fs/read_write.c > > > > +++ b/fs/read_write.c > > > > @@ -1570,6 +1570,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, > > > > if (unlikely(ret)) > > > > return ret; > > > > > > > > + if (pos_in >= i_size_read(inode_in)) > > > > + return -EINVAL; > > > > + > > > > if (!(file_in->f_mode & FMODE_READ) || > > > > !(file_out->f_mode & FMODE_WRITE) || > > > > (file_out->f_flags & O_APPEND)) > > > > -- > > > > 1.8.3.1
On Wed, Oct 31, 2018 at 02:01:45PM -0400, Olga Kornievskaia wrote: > On Wed, Oct 31, 2018 at 1:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > > > On Wed, Oct 31, 2018 at 01:07:11PM -0400, Olga Kornievskaia wrote: > > > On Wed, Oct 31, 2018 at 12:54 PM J. Bruce Fields <bfields@fieldses.org> wrote: > > > > > > > > On Fri, Oct 19, 2018 at 11:28:53AM -0400, Olga Kornievskaia wrote: > > > > > From: Anna Schumaker <Anna.Schumaker@Netapp.com> > > > > > > > > I have some idea we've had some discussion about this before, but if so > > > > I've forgotten the conclusion. Could we have more of a changelog?: > > > > > > > > - isn't there a race condition, or is there something preventing > > > > the file size from changing here? > > > > > > No there is nothing preventing the size from changing. Just like there > > > is nothing that prevents the file from changing if you are doing a > > > traditional copy either. > > > > > > > - why are we doing this? Does this change the behavior of > > > > copy_file_range()? > > > > > > We are doing this because 1. NFS spec and 2. copy_file_range semantics > > > mandate that too. There is a whole different discussion under the > > > client-side patch for this where the plan now is that VFS themselves > > > are interested in making sure they are indeed enforcing the check > > > stated by the documentation of copy_file_range call which states > > > "copying a range beyond the end of the file" is EINVAL. I recall you > > > argued for a "short" read instead of a EINVAL but unless VFS community > > > is convinced to change it it'll be enforced (soon). > > > > OK. Let's just make sure the reasoning's mentioned in the changelog, > > whatever we do. > > By the changelog, you mean the commit message? Right.--b.
diff --git a/fs/read_write.c b/fs/read_write.c index 39b4a21..c60790f 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1570,6 +1570,9 @@ ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, if (unlikely(ret)) return ret; + if (pos_in >= i_size_read(inode_in)) + return -EINVAL; + if (!(file_in->f_mode & FMODE_READ) || !(file_out->f_mode & FMODE_WRITE) || (file_out->f_flags & O_APPEND))