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Subject[PATCH 37/39] Partially revert "locks: fix file locking on overlayfs"
Date
This partially reverts commit c568d68341be7030f5647def68851e469b21ca11.

Overlayfs files will now automatically get the correct locks, no need to
hack overlay support in VFS.

It is a partial revert, because it leaves the locks_inode() calls in place
and defines locks_inode() to file_inode(). We could revert those as well,
but it would be unnecessary code churn and it makes sense to document that
we are getting the inode for locking purposes.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
---
fs/locks.c | 17 ++++++-----------
fs/overlayfs/super.c | 2 +-
include/linux/fs.h | 13 +------------
include/uapi/linux/fs.h | 1 -
4 files changed, 8 insertions(+), 25 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index 9c0e5f3da66c..40bcbaaa3f52 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -139,11 +139,6 @@
#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
#define IS_REMOTELCK(fl) (fl->fl_pid <= 0)

-static inline bool is_remote_lock(struct file *filp)
-{
- return likely(!(filp->f_path.dentry->d_sb->s_flags & SB_NOREMOTELOCK));
-}
-
static bool lease_breaking(struct file_lock *fl)
{
return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
@@ -1875,7 +1870,7 @@ EXPORT_SYMBOL(generic_setlease);
int
vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv)
{
- if (filp->f_op->setlease && is_remote_lock(filp))
+ if (filp->f_op->setlease)
return filp->f_op->setlease(filp, arg, lease, priv);
else
return generic_setlease(filp, arg, lease, priv);
@@ -2022,7 +2017,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
if (error)
goto out_free;

- if (f.file->f_op->flock && is_remote_lock(f.file))
+ if (f.file->f_op->flock)
error = f.file->f_op->flock(f.file,
(can_sleep) ? F_SETLKW : F_SETLK,
lock);
@@ -2048,7 +2043,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
*/
int vfs_test_lock(struct file *filp, struct file_lock *fl)
{
- if (filp->f_op->lock && is_remote_lock(filp))
+ if (filp->f_op->lock)
return filp->f_op->lock(filp, F_GETLK, fl);
posix_test_lock(filp, fl);
return 0;
@@ -2191,7 +2186,7 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
*/
int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
{
- if (filp->f_op->lock && is_remote_lock(filp))
+ if (filp->f_op->lock)
return filp->f_op->lock(filp, cmd, fl);
else
return posix_lock_file(filp, fl, conf);
@@ -2513,7 +2508,7 @@ locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
if (list_empty(&flctx->flc_flock))
return;

- if (filp->f_op->flock && is_remote_lock(filp))
+ if (filp->f_op->flock)
filp->f_op->flock(filp, F_SETLKW, &fl);
else
flock_lock_inode(inode, &fl);
@@ -2600,7 +2595,7 @@ EXPORT_SYMBOL(posix_unblock_lock);
*/
int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
{
- if (filp->f_op->lock && is_remote_lock(filp))
+ if (filp->f_op->lock)
return filp->f_op->lock(filp, F_CANCELLK, fl);
return 0;
}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 4bca84a17c43..d7df69e5b674 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1478,7 +1478,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_op = &ovl_super_operations;
sb->s_xattr = ovl_xattr_handlers;
sb->s_fs_info = ofs;
- sb->s_flags |= SB_POSIXACL | SB_NOREMOTELOCK;
+ sb->s_flags |= SB_POSIXACL;

err = -ENOMEM;
root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 797d6f28a8f0..7471a4208fdc 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1050,17 +1050,7 @@ struct file_lock_context {

extern void send_sigio(struct fown_struct *fown, int fd, int band);

-/*
- * Return the inode to use for locking
- *
- * For overlayfs this should be the overlay inode, not the real inode returned
- * by file_inode(). For any other fs file_inode(filp) and locks_inode(filp) are
- * equal.
- */
-static inline struct inode *locks_inode(const struct file *f)
-{
- return f->f_path.dentry->d_inode;
-}
+#define locks_inode(f) file_inode(f)

#ifdef CONFIG_FILE_LOCKING
extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
@@ -1300,7 +1290,6 @@ extern int send_sigurg(struct fown_struct *fown);

/* These sb flags are internal to the kernel */
#define SB_SUBMOUNT (1<<26)
-#define SB_NOREMOTELOCK (1<<27)
#define SB_NOSEC (1<<28)
#define SB_BORN (1<<29)
#define SB_ACTIVE (1<<30)
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index d2a8313fabd7..2840ddcece73 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -134,7 +134,6 @@ struct inodes_stat_t {

/* These sb flags are internal to the kernel */
#define MS_SUBMOUNT (1<<26)
-#define MS_NOREMOTELOCK (1<<27)
#define MS_NOSEC (1<<28)
#define MS_BORN (1<<29)
#define MS_ACTIVE (1<<30)
--
2.14.3
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