| Message ID | 1504597596-17994-2-git-send-email-mszeredi@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Sep 5, 2017 at 10:46 AM, Miklos Szeredi <mszeredi@redhat.com> wrote: > Add a separate flags argument (in addition to the open flags) to control > the behavior of d_real(). > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > --- ... > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > > static struct dentry *ovl_d_real(struct dentry *dentry, > const struct inode *inode, > - unsigned int open_flags) > + unsigned int open_flags, unsigned int flags) > { > struct dentry *real; > int err; > @@ -102,7 +102,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry, > goto bug; > > /* Handle recursion */ > - real = d_real(real, inode, open_flags); > + real = d_real(real, inode, open_flags, 0); > Shouldn't recursion pass on flags? The answer is probably per flag. The 2 currently proposed flags don't end up in recursion anyway, although it is arguable that D_REAL_ALL should end up in recursion because according to comment it should behave the same as d_real for regular files. For the purpose for which D_REAL_ALL was proposed (atime update) the recursion case doesn't really matter. Maybe a flag D_REAL_NORECURSE and then for update_ovl_inode_times() use D_REAL_ALL|D_REAL_NORECURSE Alternatively, update_ovl_inode_times() could use D_REAL_UPPER and then we explicitly say that we don't care about lower mtime/ctime modifications. Amir.
On Tue, Sep 5, 2017 at 10:55 AM, Amir Goldstein <amir73il@gmail.com> wrote: > On Tue, Sep 5, 2017 at 10:46 AM, Miklos Szeredi <mszeredi@redhat.com> wrote: >> Add a separate flags argument (in addition to the open flags) to control >> the behavior of d_real(). >> >> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> >> --- > ... >> --- a/fs/overlayfs/super.c >> +++ b/fs/overlayfs/super.c >> >> static struct dentry *ovl_d_real(struct dentry *dentry, >> const struct inode *inode, >> - unsigned int open_flags) >> + unsigned int open_flags, unsigned int flags) >> { >> struct dentry *real; >> int err; >> @@ -102,7 +102,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry, >> goto bug; >> >> /* Handle recursion */ >> - real = d_real(real, inode, open_flags); >> + real = d_real(real, inode, open_flags, 0); >> > > Shouldn't recursion pass on flags? > The answer is probably per flag. > The 2 currently proposed flags don't end up in recursion anyway, > although it is arguable that D_REAL_ALL should end up in recursion > because according to comment it should behave the same as > d_real for regular files. > > For the purpose for which D_REAL_ALL was proposed (atime update) > the recursion case doesn't really matter. > > Maybe a flag D_REAL_NORECURSE and then for > update_ovl_inode_times() use D_REAL_ALL|D_REAL_NORECURSE > > Alternatively, update_ovl_inode_times() could use D_REAL_UPPER > and then we explicitly say that we don't care about lower mtime/ctime > modifications. Well, D_REAL_ALL imples nonrecurse. Maybe that needs better documentation (comment above in ovl_d_real()) but I don't otherwise see a problem with the current state of affairs. Thanks, Miklos
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index fe25787ff6d4..75d2d57e2c44 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -22,7 +22,7 @@ prototypes: struct vfsmount *(*d_automount)(struct path *path); int (*d_manage)(const struct path *, bool); struct dentry *(*d_real)(struct dentry *, const struct inode *, - unsigned int); + unsigned int, unsigned int); locking rules: rename_lock ->d_lock may block rcu-walk diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 73e7d91f03dc..7f20c1bdfb67 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -990,7 +990,7 @@ struct dentry_operations { struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(const struct path *, bool); struct dentry *(*d_real)(struct dentry *, const struct inode *, - unsigned int); + unsigned int, unsigned int); }; d_revalidate: called when the VFS needs to revalidate a dentry. This diff --git a/fs/open.c b/fs/open.c index 35bb784763a4..6d5c9a9b8c8d 100644 --- a/fs/open.c +++ b/fs/open.c @@ -96,7 +96,7 @@ long vfs_truncate(const struct path *path, loff_t length) * write access on the upper inode, not on the overlay inode. For * non-overlay filesystems d_real() is an identity function. */ - upperdentry = d_real(path->dentry, NULL, O_WRONLY); + upperdentry = d_real(path->dentry, NULL, O_WRONLY, 0); error = PTR_ERR(upperdentry); if (IS_ERR(upperdentry)) goto mnt_drop_write_and_out; @@ -857,7 +857,7 @@ EXPORT_SYMBOL(file_path); int vfs_open(const struct path *path, struct file *file, const struct cred *cred) { - struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags); + struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags, 0); if (IS_ERR(dentry)) return PTR_ERR(dentry); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index c0c02cca776b..19e89ce39017 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -70,7 +70,7 @@ static int ovl_check_append_only(struct inode *inode, int flag) static struct dentry *ovl_d_real(struct dentry *dentry, const struct inode *inode, - unsigned int open_flags) + unsigned int open_flags, unsigned int flags) { struct dentry *real; int err; @@ -102,7 +102,7 @@ static struct dentry *ovl_d_real(struct dentry *dentry, goto bug; /* Handle recursion */ - real = d_real(real, inode, open_flags); + real = d_real(real, inode, open_flags, 0); if (!inode || inode == d_inode(real)) return real; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index aae1cdb76851..fd0721e520f4 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -147,7 +147,7 @@ struct dentry_operations { struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(const struct path *, bool); struct dentry *(*d_real)(struct dentry *, const struct inode *, - unsigned int); + unsigned int, unsigned int); } ____cacheline_aligned; /* @@ -566,7 +566,8 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper) * d_real - Return the real dentry * @dentry: the dentry to query * @inode: inode to select the dentry from multiple layers (can be NULL) - * @flags: open flags to control copy-up behavior + * @open_flags: open flags to control copy-up behavior + * @flags: flags to control what is returned by this function * * If dentry is on a union/overlay, then return the underlying, real dentry. * Otherwise return the dentry itself. @@ -575,10 +576,10 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper) */ static inline struct dentry *d_real(struct dentry *dentry, const struct inode *inode, - unsigned int flags) + unsigned int open_flags, unsigned int flags) { if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) - return dentry->d_op->d_real(dentry, inode, flags); + return dentry->d_op->d_real(dentry, inode, open_flags, flags); else return dentry; } @@ -593,7 +594,7 @@ static inline struct dentry *d_real(struct dentry *dentry, static inline struct inode *d_real_inode(const struct dentry *dentry) { /* This usage of d_real() results in const dentry */ - return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0)); + return d_backing_inode(d_real((struct dentry *) dentry, NULL, 0, 0)); } struct name_snapshot { diff --git a/include/linux/fs.h b/include/linux/fs.h index 6e1fd5d21248..ee1db83c39cb 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1233,7 +1233,7 @@ static inline struct inode *file_inode(const struct file *f) static inline struct dentry *file_dentry(const struct file *file) { - return d_real(file->f_path.dentry, file_inode(file), 0); + return d_real(file->f_path.dentry, file_inode(file), 0, 0); } static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
Add a separate flags argument (in addition to the open flags) to control the behavior of d_real(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> --- Documentation/filesystems/Locking | 2 +- Documentation/filesystems/vfs.txt | 2 +- fs/open.c | 4 ++-- fs/overlayfs/super.c | 4 ++-- include/linux/dcache.h | 11 ++++++----- include/linux/fs.h | 2 +- 6 files changed, 13 insertions(+), 12 deletions(-)