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Partially revert "locks: fix file locking on overlayfs"

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This partially reverts commit c568d68341.

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.

Don't revert MS_NOREMOTELOCK yet since that has been part of the userspace
API for some time (though not in a useful way).  Will try to remove
internal flags later when the dust around the new mount API settles.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
This commit is contained in:
Miklos Szeredi 2018-07-18 15:44:43 +02:00
parent 8cf9ee5061
commit de2a4a501e
3 changed files with 8 additions and 24 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

17
fs/locks.c
View file

@ -139,11 +139,6 @@
#define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK) #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK)
#define IS_REMOTELCK(fl) (fl->fl_pid <= 0) #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) static bool lease_breaking(struct file_lock *fl)
{ {
return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
@ -1875,7 +1870,7 @@ EXPORT_SYMBOL(generic_setlease);
int int
vfs_setlease(struct file *filp, long arg, struct file_lock **lease, void **priv) 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); return filp->f_op->setlease(filp, arg, lease, priv);
else else
return generic_setlease(filp, arg, lease, priv); return generic_setlease(filp, arg, lease, priv);
@ -2022,7 +2017,7 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
if (error) if (error)
goto out_free; 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, error = f.file->f_op->flock(f.file,
(can_sleep) ? F_SETLKW : F_SETLK, (can_sleep) ? F_SETLKW : F_SETLK,
lock); 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) 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); return filp->f_op->lock(filp, F_GETLK, fl);
posix_test_lock(filp, fl); posix_test_lock(filp, fl);
return 0; 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) 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); return filp->f_op->lock(filp, cmd, fl);
else else
return posix_lock_file(filp, fl, conf); 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)) if (list_empty(&flctx->flc_flock))
return; return;
if (filp->f_op->flock && is_remote_lock(filp)) if (filp->f_op->flock)
filp->f_op->flock(filp, F_SETLKW, &fl); filp->f_op->flock(filp, F_SETLKW, &fl);
else else
flock_lock_inode(inode, &fl); 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) 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 filp->f_op->lock(filp, F_CANCELLK, fl);
return 0; return 0;
} }

2
fs/overlayfs/super.c
View file

@ -1456,7 +1456,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent)
sb->s_op = &ovl_super_operations; sb->s_op = &ovl_super_operations;
sb->s_xattr = ovl_xattr_handlers; sb->s_xattr = ovl_xattr_handlers;
sb->s_fs_info = ofs; sb->s_fs_info = ofs;
sb->s_flags |= SB_POSIXACL | SB_NOREMOTELOCK; sb->s_flags |= SB_POSIXACL;
err = -ENOMEM; err = -ENOMEM;
root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0));

13
include/linux/fs.h
View file

@ -1054,17 +1054,7 @@ struct file_lock_context {
extern void send_sigio(struct fown_struct *fown, int fd, int band); extern void send_sigio(struct fown_struct *fown, int fd, int band);
/* #define locks_inode(f) file_inode(f)
* 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;
}
#ifdef CONFIG_FILE_LOCKING #ifdef CONFIG_FILE_LOCKING
extern int fcntl_getlk(struct file *, unsigned int, struct flock *); extern int fcntl_getlk(struct file *, unsigned int, struct flock *);
@ -1305,7 +1295,6 @@ extern int send_sigurg(struct fown_struct *fown);
/* These sb flags are internal to the kernel */ /* These sb flags are internal to the kernel */
#define SB_SUBMOUNT (1<<26) #define SB_SUBMOUNT (1<<26)
#define SB_NOREMOTELOCK (1<<27)
#define SB_NOSEC (1<<28) #define SB_NOSEC (1<<28)
#define SB_BORN (1<<29) #define SB_BORN (1<<29)
#define SB_ACTIVE (1<<30) #define SB_ACTIVE (1<<30)