On Thu, Jun 25, 2020 at 08:39:54PM +0000, Frank van der Linden wrote: > Hi Al, > > Do you have any comments / concerns about this patch? It's part of nfs > server side user xattr support, full series here: > > https://lore.kernel.org/linux-nfs/20200623223927.31795-1-fllinden@xxxxxxxxxx/ > > I copied this one to linux-fsdevel and you, just giving you an extra > ping. Bruce/Chuck are OK with the rest of the series, so I just need > your ACK on this one, and the next one (will send the ping separately). > > Thanks, > > - Frank Hi Al, Any comments on this one? It's a simple change to break (NFSv4) delegations on set/removexattr, so it's pretty nfsd specific. Linus - since this is nfsd specific, could this go in through the nfsd maintainer tree directly? Chuck has included it in a tree that is being readied for 5.9. Thanks, - Frank > > > On Tue, Jun 23, 2020 at 10:39:18PM +0000, Frank van der Linden wrote: > > set/removexattr on an exported filesystem should break NFS delegations. > > This is true in general, but also for the upcoming support for > > RFC 8726 (NFSv4 extended attribute support). Make sure that they do. > > > > Additonally, they need to grow a _locked variant, since callers might > > call this with i_rwsem held (like the NFS server code). > > > > Cc: stable@xxxxxxxxxxxxxxx > > Cc: linux-fsdevel@xxxxxxxxxxxxxxx > > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > > Signed-off-by: Frank van der Linden <fllinden@xxxxxxxxxx> > > --- > > fs/xattr.c | 84 +++++++++++++++++++++++++++++++++++++++---- > > include/linux/xattr.h | 2 ++ > > 2 files changed, 79 insertions(+), 7 deletions(-) > > > > diff --git a/fs/xattr.c b/fs/xattr.c > > index 91608d9bfc6a..95f38f57347f 100644 > > --- a/fs/xattr.c > > +++ b/fs/xattr.c > > @@ -204,10 +204,22 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, > > return error; > > } > > > > - > > +/** > > + * __vfs_setxattr_locked: set an extended attribute while holding the inode > > + * lock > > + * > > + * @dentry - object to perform setxattr on > > + * @name - xattr name to set > > + * @value - value to set @name to > > + * @size - size of @value > > + * @flags - flags to pass into filesystem operations > > + * @delegated_inode - on return, will contain an inode pointer that > > + * a delegation was broken on, NULL if none. > > + */ > > int > > -vfs_setxattr(struct dentry *dentry, const char *name, const void *value, > > - size_t size, int flags) > > +__vfs_setxattr_locked(struct dentry *dentry, const char *name, > > + const void *value, size_t size, int flags, > > + struct inode **delegated_inode) > > { > > struct inode *inode = dentry->d_inode; > > int error; > > @@ -216,15 +228,40 @@ vfs_setxattr(struct dentry *dentry, const char *name, const void *value, > > if (error) > > return error; > > > > - inode_lock(inode); > > error = security_inode_setxattr(dentry, name, value, size, flags); > > if (error) > > goto out; > > > > + error = try_break_deleg(inode, delegated_inode); > > + if (error) > > + goto out; > > + > > error = __vfs_setxattr_noperm(dentry, name, value, size, flags); > > > > out: > > + return error; > > +} > > +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); > > + > > +int > > +vfs_setxattr(struct dentry *dentry, const char *name, const void *value, > > + size_t size, int flags) > > +{ > > + struct inode *inode = dentry->d_inode; > > + struct inode *delegated_inode = NULL; > > + int error; > > + > > +retry_deleg: > > + inode_lock(inode); > > + error = __vfs_setxattr_locked(dentry, name, value, size, flags, > > + &delegated_inode); > > inode_unlock(inode); > > + > > + if (delegated_inode) { > > + error = break_deleg_wait(&delegated_inode); > > + if (!error) > > + goto retry_deleg; > > + } > > return error; > > } > > EXPORT_SYMBOL_GPL(vfs_setxattr); > > @@ -378,8 +415,18 @@ __vfs_removexattr(struct dentry *dentry, const char *name) > > } > > EXPORT_SYMBOL(__vfs_removexattr); > > > > +/** > > + * __vfs_removexattr_locked: set an extended attribute while holding the inode > > + * lock > > + * > > + * @dentry - object to perform setxattr on > > + * @name - name of xattr to remove > > + * @delegated_inode - on return, will contain an inode pointer that > > + * a delegation was broken on, NULL if none. > > + */ > > int > > -vfs_removexattr(struct dentry *dentry, const char *name) > > +__vfs_removexattr_locked(struct dentry *dentry, const char *name, > > + struct inode **delegated_inode) > > { > > struct inode *inode = dentry->d_inode; > > int error; > > @@ -388,11 +435,14 @@ vfs_removexattr(struct dentry *dentry, const char *name) > > if (error) > > return error; > > > > - inode_lock(inode); > > error = security_inode_removexattr(dentry, name); > > if (error) > > goto out; > > > > + error = try_break_deleg(inode, delegated_inode); > > + if (error) > > + goto out; > > + > > error = __vfs_removexattr(dentry, name); > > > > if (!error) { > > @@ -401,12 +451,32 @@ vfs_removexattr(struct dentry *dentry, const char *name) > > } > > > > out: > > + return error; > > +} > > +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); > > + > > +int > > +vfs_removexattr(struct dentry *dentry, const char *name) > > +{ > > + struct inode *inode = dentry->d_inode; > > + struct inode *delegated_inode = NULL; > > + int error; > > + > > +retry_deleg: > > + inode_lock(inode); > > + error = __vfs_removexattr_locked(dentry, name, &delegated_inode); > > inode_unlock(inode); > > + > > + if (delegated_inode) { > > + error = break_deleg_wait(&delegated_inode); > > + if (!error) > > + goto retry_deleg; > > + } > > + > > return error; > > } > > EXPORT_SYMBOL_GPL(vfs_removexattr); > > > > - > > /* > > * Extended attribute SET operations > > */ > > diff --git a/include/linux/xattr.h b/include/linux/xattr.h > > index 47eaa34f8761..a2f3cd02653c 100644 > > --- a/include/linux/xattr.h > > +++ b/include/linux/xattr.h > > @@ -51,8 +51,10 @@ ssize_t vfs_getxattr(struct dentry *, const char *, void *, size_t); > > ssize_t vfs_listxattr(struct dentry *d, char *list, size_t size); > > int __vfs_setxattr(struct dentry *, struct inode *, const char *, const void *, size_t, int); > > int __vfs_setxattr_noperm(struct dentry *, const char *, const void *, size_t, int); > > +int __vfs_setxattr_locked(struct dentry *, const char *, const void *, size_t, int, struct inode **); > > int vfs_setxattr(struct dentry *, const char *, const void *, size_t, int); > > int __vfs_removexattr(struct dentry *, const char *); > > +int __vfs_removexattr_locked(struct dentry *, const char *, struct inode **); > > int vfs_removexattr(struct dentry *, const char *); > > > > ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size); > > -- > > 2.17.2 > >
