| Message ID | 1458205323-25685-1-git-send-email-miklos@szeredi.hu (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Mar 17, 2016 at 10:02 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: > From: Miklos Szeredi <mszeredi@redhat.com> > > This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make > f_path always point to the overlay and f_inode to the underlay"). > Can you put that series in your vfs.git tree? Easier for getting and testing. Thanks. - Sedat - > Regular files opened on overlayfs will result in the file being opened on > the underlying filesystem, while f_path points to the overlayfs > mount/dentry. > > This confuses filesystems which get the dentry from struct file and assume > it's theirs. > > Add a new helper, file_dentry() [*], to get the filesystem's own dentry > from the file. This simply compares file_inode(file->f_path.dentry) to > file_inode(file) and if they are equal returns file->f_path.dentry (this is > the common, non-overlayfs case). > > In the uncommon case (regular file on overlayfs) it will call into > overlayfs's ->d_native_dentry() to get the underlying dentry matching > file_inode(file). > > [*] If possible, it's better simply to use file_inode() instead. > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> > Cc: <stable@vger.kernel.org> # v4.2 > Cc: David Howells <dhowells@redhat.com> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: Theodore Ts'o <tytso@mit.edu> > Cc: Daniel Axtens <dja@axtens.net> > --- > fs/open.c | 11 +++++++++++ > fs/overlayfs/super.c | 16 ++++++++++++++++ > include/linux/dcache.h | 1 + > include/linux/fs.h | 2 ++ > 4 files changed, 30 insertions(+) > > diff --git a/fs/open.c b/fs/open.c > index 55bdc75e2172..6326c11eda78 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen) > } > EXPORT_SYMBOL(file_path); > > +struct dentry *file_dentry(const struct file *file) > +{ > + struct dentry *dentry = file->f_path.dentry; > + > + if (likely(d_inode(dentry) == file_inode(file))) > + return dentry; > + else > + return dentry->d_op->d_native_dentry(dentry, file_inode(file)); > +} > +EXPORT_SYMBOL(file_dentry); > + > /** > * vfs_open - open the file at the given path > * @path: path to open > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index 619ad4b016d2..5142aa2034c4 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -336,14 +336,30 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) > return ret; > } > > +static struct dentry *ovl_d_native_dentry(struct dentry *dentry, > + struct inode *inode) > +{ > + struct ovl_entry *oe = dentry->d_fsdata; > + struct dentry *realentry = ovl_upperdentry_dereference(oe); > + > + if (realentry && inode == d_inode(realentry)) > + return realentry; > + realentry = __ovl_dentry_lower(oe); > + if (realentry && inode == d_inode(realentry)) > + return realentry; > + BUG(); > +} > + > static const struct dentry_operations ovl_dentry_operations = { > .d_release = ovl_dentry_release, > .d_select_inode = ovl_d_select_inode, > + .d_native_dentry = ovl_d_native_dentry, > }; > > static const struct dentry_operations ovl_reval_dentry_operations = { > .d_release = ovl_dentry_release, > .d_select_inode = ovl_d_select_inode, > + .d_native_dentry = ovl_d_native_dentry, > .d_revalidate = ovl_dentry_revalidate, > .d_weak_revalidate = ovl_dentry_weak_revalidate, > }; > diff --git a/include/linux/dcache.h b/include/linux/dcache.h > index c4b5f4b3f8f8..99ecb6de636c 100644 > --- a/include/linux/dcache.h > +++ b/include/linux/dcache.h > @@ -161,6 +161,7 @@ struct dentry_operations { > struct vfsmount *(*d_automount)(struct path *); > int (*d_manage)(struct dentry *, bool); > struct inode *(*d_select_inode)(struct dentry *, unsigned); > + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *); > } ____cacheline_aligned; > > /* > diff --git a/include/linux/fs.h b/include/linux/fs.h > index ae681002100a..1091d9f43271 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1234,6 +1234,8 @@ static inline struct inode *file_inode(const struct file *f) > return f->f_inode; > } > > +extern struct dentry *file_dentry(const struct file *file); > + > static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) > { > return locks_lock_inode_wait(file_inode(filp), fl); > -- > 2.1.4 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 10:09 AM, Sedat Dilek <sedat.dilek@gmail.com> wrote: > On Thu, Mar 17, 2016 at 10:02 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: >> From: Miklos Szeredi <mszeredi@redhat.com> >> >> This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make >> f_path always point to the overlay and f_inode to the underlay"). >> > > Can you put that series in your vfs.git tree? > Easier for getting and testing. Ok, pushed to: git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git file_dentry Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 10:33 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: > On Thu, Mar 17, 2016 at 10:09 AM, Sedat Dilek <sedat.dilek@gmail.com> wrote: >> On Thu, Mar 17, 2016 at 10:02 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: >>> From: Miklos Szeredi <mszeredi@redhat.com> >>> >>> This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make >>> f_path always point to the overlay and f_inode to the underlay"). >>> >> >> Can you put that series in your vfs.git tree? >> Easier for getting and testing. > > Ok, pushed to: > > git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git file_dentry > Is that correct the ext4-related patches 3/4 and 4/4 are Linux-v4.5 material? Not applicable fpr v4.4.y-stable? - Sedat - -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 11:15 AM, Sedat Dilek <sedat.dilek@gmail.com> wrote: > On Thu, Mar 17, 2016 at 10:33 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: >> On Thu, Mar 17, 2016 at 10:09 AM, Sedat Dilek <sedat.dilek@gmail.com> wrote: >>> On Thu, Mar 17, 2016 at 10:02 AM, Miklos Szeredi <miklos@szeredi.hu> wrote: >>>> From: Miklos Szeredi <mszeredi@redhat.com> >>>> >>>> This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make >>>> f_path always point to the overlay and f_inode to the underlay"). >>>> >>> >>> Can you put that series in your vfs.git tree? >>> Easier for getting and testing. >> >> Ok, pushed to: >> >> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git file_dentry >> > > Is that correct the ext4-related patches 3/4 and 4/4 are Linux-v4.5 material? > Not applicable fpr v4.4.y-stable? > Sorry, for disturbing again - parallelly building some other software which needs my attention. Why didn't you split 1/4 into a vfs (generic) part and overlayfs (related) part? Thinking of bisecting or backporting ovl fixes. Just my €0,02. - Sedat - -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 11:15:26AM +0100, Sedat Dilek wrote: > > Is that correct the ext4-related patches 3/4 and 4/4 are Linux-v4.5 material? > Not applicable fpr v4.4.y-stable? 4.5 has already been released, but I think these patches are suitable for the v4.[345].y-stable branch (which I think is the question you are really asking). Al, are you willing to push all of these to Linus before the merge window closes, with a cc to stable@vger.kernel.org? Or I can push them to linus via the ext4.git tree if I get signoffs/acked-by's from the VFS and NFS maintainers. I'll want to do a full a regression test cycle since we're pushing patches created after the merge window opened, but I consider these bug fixes and will certainly support pushing them to Linus as far as ext4 is concerned. Cheers, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 10:02:00AM +0100, Miklos Szeredi wrote: > From: Miklos Szeredi <mszeredi@redhat.com> > > This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make > f_path always point to the overlay and f_inode to the underlay"). > > Regular files opened on overlayfs will result in the file being opened on > the underlying filesystem, while f_path points to the overlayfs > mount/dentry. > > This confuses filesystems which get the dentry from struct file and assume > it's theirs. > > Add a new helper, file_dentry() [*], to get the filesystem's own dentry > from the file. This simply compares file_inode(file->f_path.dentry) to > file_inode(file) and if they are equal returns file->f_path.dentry (this is > the common, non-overlayfs case). > > In the uncommon case (regular file on overlayfs) it will call into > overlayfs's ->d_native_dentry() to get the underlying dentry matching > file_inode(file). > > [*] If possible, it's better simply to use file_inode() instead. > > Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> > Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> > Cc: <stable@vger.kernel.org> # v4.2 > Cc: David Howells <dhowells@redhat.com> > Cc: Al Viro <viro@zeniv.linux.org.uk> > Cc: Theodore Ts'o <tytso@mit.edu> > Cc: Daniel Axtens <dja@axtens.net> > --- > fs/open.c | 11 +++++++++++ > fs/overlayfs/super.c | 16 ++++++++++++++++ > include/linux/dcache.h | 1 + > include/linux/fs.h | 2 ++ > 4 files changed, 30 insertions(+) I have this patch in the ext4.git tree, but I'd like to get an Acked-by from Al before I send a pull request to Linus. Al? Any objections to my sending in this change via the ext4 tree? - Ted > > diff --git a/fs/open.c b/fs/open.c > index 55bdc75e2172..6326c11eda78 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen) > } > EXPORT_SYMBOL(file_path); > > +struct dentry *file_dentry(const struct file *file) > +{ > + struct dentry *dentry = file->f_path.dentry; > + > + if (likely(d_inode(dentry) == file_inode(file))) > + return dentry; > + else > + return dentry->d_op->d_native_dentry(dentry, file_inode(file)); > +} > +EXPORT_SYMBOL(file_dentry); > + > /** > * vfs_open - open the file at the given path > * @path: path to open > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index 619ad4b016d2..5142aa2034c4 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -336,14 +336,30 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) > return ret; > } > > +static struct dentry *ovl_d_native_dentry(struct dentry *dentry, > + struct inode *inode) > +{ > + struct ovl_entry *oe = dentry->d_fsdata; > + struct dentry *realentry = ovl_upperdentry_dereference(oe); > + > + if (realentry && inode == d_inode(realentry)) > + return realentry; > + realentry = __ovl_dentry_lower(oe); > + if (realentry && inode == d_inode(realentry)) > + return realentry; > + BUG(); > +} > + > static const struct dentry_operations ovl_dentry_operations = { > .d_release = ovl_dentry_release, > .d_select_inode = ovl_d_select_inode, > + .d_native_dentry = ovl_d_native_dentry, > }; > > static const struct dentry_operations ovl_reval_dentry_operations = { > .d_release = ovl_dentry_release, > .d_select_inode = ovl_d_select_inode, > + .d_native_dentry = ovl_d_native_dentry, > .d_revalidate = ovl_dentry_revalidate, > .d_weak_revalidate = ovl_dentry_weak_revalidate, > }; > diff --git a/include/linux/dcache.h b/include/linux/dcache.h > index c4b5f4b3f8f8..99ecb6de636c 100644 > --- a/include/linux/dcache.h > +++ b/include/linux/dcache.h > @@ -161,6 +161,7 @@ struct dentry_operations { > struct vfsmount *(*d_automount)(struct path *); > int (*d_manage)(struct dentry *, bool); > struct inode *(*d_select_inode)(struct dentry *, unsigned); > + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *); > } ____cacheline_aligned; > > /* > diff --git a/include/linux/fs.h b/include/linux/fs.h > index ae681002100a..1091d9f43271 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1234,6 +1234,8 @@ static inline struct inode *file_inode(const struct file *f) > return f->f_inode; > } > > +extern struct dentry *file_dentry(const struct file *file); > + > static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) > { > return locks_lock_inode_wait(file_inode(filp), fl); > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 21, 2016 at 01:02:15AM -0400, Theodore Ts'o wrote: > I have this patch in the ext4.git tree, but I'd like to get an > Acked-by from Al before I send a pull request to Linus. > > Al? Any objections to my sending in this change via the ext4 tree? > - Ted FWIW, I would rather add DCACHE_OP_REAL (set at d_set_d_op() time) and turned that into static inline struct dentry *d_real(const struct dentry *dentry) { if (unlikely(dentry->d_flags & DCACHE_OP_NATIVE_DENTRY)) returd dentry->d_op->d_real(dentry); else return dentry; } static inline struct dentry *file_dentry(const struct file *file) { return d_real(file->f_path.dentry); } and used ovl_dentry_real as ->d_real for overlayfs. Miklos, do you see any problems with that variant? -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Mar 17, 2016 at 10:02:00AM +0100, Miklos Szeredi wrote: > Add a new helper, file_dentry() [*], to get the filesystem's own dentry > from the file. This simply compares file_inode(file->f_path.dentry) to > file_inode(file) and if they are equal returns file->f_path.dentry (this is > the common, non-overlayfs case). > > In the uncommon case (regular file on overlayfs) it will call into > overlayfs's ->d_native_dentry() to get the underlying dentry matching > file_inode(file). What's wrong with making ovl_dentry_real() an instance of optional ->d_real() method and having a flag (DCACHE_OP_REAL) controlling its calls? With d_real(dentry) returning either that or dentry itself, and file_dentry(file) being simply d_real(file->f_path.dentry)... Why do we need to look at the inode at all? d_set_d_op() dereferences ->d_op anyway, as well as setting ->d_flags, so there's no extra cost there, and "test bit in ->d_flags + branch not taken" is all it would cost in normal case... -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 21, 2016 at 6:28 AM, Al Viro <viro@zeniv.linux.org.uk> wrote: > On Thu, Mar 17, 2016 at 10:02:00AM +0100, Miklos Szeredi wrote: >> Add a new helper, file_dentry() [*], to get the filesystem's own dentry >> from the file. This simply compares file_inode(file->f_path.dentry) to >> file_inode(file) and if they are equal returns file->f_path.dentry (this is >> the common, non-overlayfs case). >> >> In the uncommon case (regular file on overlayfs) it will call into >> overlayfs's ->d_native_dentry() to get the underlying dentry matching >> file_inode(file). > > What's wrong with making ovl_dentry_real() an instance of optional > ->d_real() method and having a flag (DCACHE_OP_REAL) controlling its > calls? With d_real(dentry) returning either that or dentry itself, > and file_dentry(file) being simply d_real(file->f_path.dentry)... > > Why do we need to look at the inode at all? d_set_d_op() dereferences > ->d_op anyway, as well as setting ->d_flags, so there's no extra cost > there, and "test bit in ->d_flags + branch not taken" is all it would > cost in normal case... Checking DCACHE_OP_REAL insted of inode would be fine. But d_real() needs inode as well. Consider the case where 1) file opened on lower layer 2) copied up 3) file_dentry() called d_real(file->f_path.dentry) would return the upper dentry but that's not what we want. Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
>> From: Miklos Szeredi <mszeredi@redhat.com> >> >> This series fixes bugs in nfs and ext4 due to 4bacc9c9234c ("overlayfs: Make >> f_path always point to the overlay and f_inode to the underlay"). >> >> Regular files opened on overlayfs will result in the file being opened on >> the underlying filesystem, while f_path points to the overlayfs >> mount/dentry. >> >> This confuses filesystems which get the dentry from struct file and assume >> it's theirs. >> >> Add a new helper, file_dentry() [*], to get the filesystem's own dentry >> from the file. This simply compares file_inode(file->f_path.dentry) to >> file_inode(file) and if they are equal returns file->f_path.dentry (this is >> the common, non-overlayfs case). >> >> In the uncommon case (regular file on overlayfs) it will call into >> overlayfs's ->d_native_dentry() to get the underlying dentry matching >> file_inode(file). >> >> [*] If possible, it's better simply to use file_inode() instead. Hopefully this is not so late as to be useless! For this entire series: Tested-by: Daniel Axtens <dja@axtens.net> Regards, Daniel >> >> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> >> Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com> >> Reviewed-by: Trond Myklebust <trond.myklebust@primarydata.com> >> Cc: <stable@vger.kernel.org> # v4.2 >> Cc: David Howells <dhowells@redhat.com> >> Cc: Al Viro <viro@zeniv.linux.org.uk> >> Cc: Theodore Ts'o <tytso@mit.edu> >> Cc: Daniel Axtens <dja@axtens.net> >> --- >> fs/open.c | 11 +++++++++++ >> fs/overlayfs/super.c | 16 ++++++++++++++++ >> include/linux/dcache.h | 1 + >> include/linux/fs.h | 2 ++ >> 4 files changed, 30 insertions(+) > > I have this patch in the ext4.git tree, but I'd like to get an > Acked-by from Al before I send a pull request to Linus. > > Al? Any objections to my sending in this change via the ext4 tree? > > - Ted > >> >> diff --git a/fs/open.c b/fs/open.c >> index 55bdc75e2172..6326c11eda78 100644 >> --- a/fs/open.c >> +++ b/fs/open.c >> @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen) >> } >> EXPORT_SYMBOL(file_path); >> >> +struct dentry *file_dentry(const struct file *file) >> +{ >> + struct dentry *dentry = file->f_path.dentry; >> + >> + if (likely(d_inode(dentry) == file_inode(file))) >> + return dentry; >> + else >> + return dentry->d_op->d_native_dentry(dentry, file_inode(file)); >> +} >> +EXPORT_SYMBOL(file_dentry); >> + >> /** >> * vfs_open - open the file at the given path >> * @path: path to open >> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c >> index 619ad4b016d2..5142aa2034c4 100644 >> --- a/fs/overlayfs/super.c >> +++ b/fs/overlayfs/super.c >> @@ -336,14 +336,30 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) >> return ret; >> } >> >> +static struct dentry *ovl_d_native_dentry(struct dentry *dentry, >> + struct inode *inode) >> +{ >> + struct ovl_entry *oe = dentry->d_fsdata; >> + struct dentry *realentry = ovl_upperdentry_dereference(oe); >> + >> + if (realentry && inode == d_inode(realentry)) >> + return realentry; >> + realentry = __ovl_dentry_lower(oe); >> + if (realentry && inode == d_inode(realentry)) >> + return realentry; >> + BUG(); >> +} >> + >> static const struct dentry_operations ovl_dentry_operations = { >> .d_release = ovl_dentry_release, >> .d_select_inode = ovl_d_select_inode, >> + .d_native_dentry = ovl_d_native_dentry, >> }; >> >> static const struct dentry_operations ovl_reval_dentry_operations = { >> .d_release = ovl_dentry_release, >> .d_select_inode = ovl_d_select_inode, >> + .d_native_dentry = ovl_d_native_dentry, >> .d_revalidate = ovl_dentry_revalidate, >> .d_weak_revalidate = ovl_dentry_weak_revalidate, >> }; >> diff --git a/include/linux/dcache.h b/include/linux/dcache.h >> index c4b5f4b3f8f8..99ecb6de636c 100644 >> --- a/include/linux/dcache.h >> +++ b/include/linux/dcache.h >> @@ -161,6 +161,7 @@ struct dentry_operations { >> struct vfsmount *(*d_automount)(struct path *); >> int (*d_manage)(struct dentry *, bool); >> struct inode *(*d_select_inode)(struct dentry *, unsigned); >> + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *); >> } ____cacheline_aligned; >> >> /* >> diff --git a/include/linux/fs.h b/include/linux/fs.h >> index ae681002100a..1091d9f43271 100644 >> --- a/include/linux/fs.h >> +++ b/include/linux/fs.h >> @@ -1234,6 +1234,8 @@ static inline struct inode *file_inode(const struct file *f) >> return f->f_inode; >> } >> >> +extern struct dentry *file_dentry(const struct file *file); >> + >> static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) >> { >> return locks_lock_inode_wait(file_inode(filp), fl); >> -- >> 2.1.4 >> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/open.c b/fs/open.c index 55bdc75e2172..6326c11eda78 100644 --- a/fs/open.c +++ b/fs/open.c @@ -831,6 +831,17 @@ char *file_path(struct file *filp, char *buf, int buflen) } EXPORT_SYMBOL(file_path); +struct dentry *file_dentry(const struct file *file) +{ + struct dentry *dentry = file->f_path.dentry; + + if (likely(d_inode(dentry) == file_inode(file))) + return dentry; + else + return dentry->d_op->d_native_dentry(dentry, file_inode(file)); +} +EXPORT_SYMBOL(file_dentry); + /** * vfs_open - open the file at the given path * @path: path to open diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 619ad4b016d2..5142aa2034c4 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -336,14 +336,30 @@ static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) return ret; } +static struct dentry *ovl_d_native_dentry(struct dentry *dentry, + struct inode *inode) +{ + struct ovl_entry *oe = dentry->d_fsdata; + struct dentry *realentry = ovl_upperdentry_dereference(oe); + + if (realentry && inode == d_inode(realentry)) + return realentry; + realentry = __ovl_dentry_lower(oe); + if (realentry && inode == d_inode(realentry)) + return realentry; + BUG(); +} + static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, .d_select_inode = ovl_d_select_inode, + .d_native_dentry = ovl_d_native_dentry, }; static const struct dentry_operations ovl_reval_dentry_operations = { .d_release = ovl_dentry_release, .d_select_inode = ovl_d_select_inode, + .d_native_dentry = ovl_d_native_dentry, .d_revalidate = ovl_dentry_revalidate, .d_weak_revalidate = ovl_dentry_weak_revalidate, }; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c4b5f4b3f8f8..99ecb6de636c 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -161,6 +161,7 @@ struct dentry_operations { struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(struct dentry *, bool); struct inode *(*d_select_inode)(struct dentry *, unsigned); + struct dentry *(*d_native_dentry)(struct dentry *, struct inode *); } ____cacheline_aligned; /* diff --git a/include/linux/fs.h b/include/linux/fs.h index ae681002100a..1091d9f43271 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1234,6 +1234,8 @@ static inline struct inode *file_inode(const struct file *f) return f->f_inode; } +extern struct dentry *file_dentry(const struct file *file); + static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) { return locks_lock_inode_wait(file_inode(filp), fl);