From: Miklos Szeredi <mszeredi@redhat.com>
To: linux-unionfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 34/35] vfs: simplify d_op->d_real()
Date: Thu, 12 Apr 2018 17:08:25 +0200 [thread overview]
Message-ID: <20180412150826.20988-35-mszeredi@redhat.com> (raw)
In-Reply-To: <20180412150826.20988-1-mszeredi@redhat.com>
The only remaining user of d_real() is file_dentry().
Simplify code related to ->d_real() by:
- remove dead code from overlayfs implementation
- remove the open_flags argument
- expand d_real() helper into file_dentry()
- remove d_real() helper, since there are no callers and makes no sense to
add new ones
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
Documentation/filesystems/Locking | 3 +--
Documentation/filesystems/vfs.txt | 22 +++-------------
fs/overlayfs/super.c | 55 +++++++--------------------------------
include/linux/dcache.h | 24 +----------------
include/linux/fs.h | 7 ++++-
5 files changed, 21 insertions(+), 90 deletions(-)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index a4afe96f0112..e1d7e43d302c 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -21,8 +21,7 @@ prototypes:
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
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);
+ struct dentry *(*d_real)(struct dentry *, const struct inode *);
locking rules:
rename_lock ->d_lock may block rcu-walk
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index af54d3651ff8..632d5c58fde9 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -990,8 +990,7 @@ struct dentry_operations {
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(const struct path *, bool);
- struct dentry *(*d_real)(struct dentry *, const struct inode *,
- unsigned int);
+ struct dentry *(*d_real)(struct dentry *, const struct inode *);
};
d_revalidate: called when the VFS needs to revalidate a dentry. This
@@ -1124,23 +1123,8 @@ struct dentry_operations {
This function is only used if DCACHE_MANAGE_TRANSIT is set on the
dentry being transited from.
- d_real: overlay/union type filesystems implement this method to return one of
- the underlying dentries hidden by the overlay. It is used in three
- different modes:
-
- Called from open it may need to copy-up the file depending on the
- supplied open flags. This mode is selected with a non-zero flags
- argument. In this mode the d_real method can return an error.
-
- Called from file_dentry() it returns the real dentry matching the inode
- argument. The real dentry may be from a lower layer already copied up,
- but still referenced from the file. This mode is selected with a
- non-NULL inode argument. This will always succeed.
-
- With NULL inode and zero flags the topmost real underlying dentry is
- returned. This will always succeed.
-
- This method is never called with both non-NULL inode and non-zero flags.
+ d_real: This is called from file_dentry(). It returns the real dentry
+ matching the inode argument.
Each dentry has a pointer to its parent dentry, as well as a hash list
of child dentries. Child dentries are basically like files in a
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index f2a83fabe2eb..ab1642fcece3 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -80,64 +80,29 @@ static void ovl_dentry_release(struct dentry *dentry)
}
}
-static int ovl_check_append_only(struct inode *inode, int flag)
-{
- /*
- * This test was moot in vfs may_open() because overlay inode does
- * not have the S_APPEND flag, so re-check on real upper inode
- */
- if (IS_APPEND(inode)) {
- if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND))
- return -EPERM;
- if (flag & O_TRUNC)
- return -EPERM;
- }
-
- return 0;
-}
-
static struct dentry *ovl_d_real(struct dentry *dentry,
- const struct inode *inode,
- unsigned int open_flags)
+ const struct inode *inode)
{
struct dentry *real;
- int err;
+
+ if (WARN_ON(!inode))
+ return dentry;
/* It's an overlay file */
- if (inode && d_inode(dentry) == inode)
+ if (d_inode(dentry) == inode)
return dentry;
- if (!d_is_reg(dentry)) {
- if (!inode || inode == d_inode(dentry))
- return dentry;
+ if (!d_is_reg(dentry))
goto bug;
- }
- if (open_flags) {
- err = ovl_open_maybe_copy_up(dentry, open_flags);
- if (err)
- return ERR_PTR(err);
- }
-
- real = ovl_dentry_upper(dentry);
- if (real && (!inode || inode == d_inode(real))) {
- if (!inode) {
- err = ovl_check_append_only(d_inode(real), open_flags);
- if (err)
- return ERR_PTR(err);
- }
+ real = ovl_dentry_real(dentry);
+ if (inode == d_inode(real))
return real;
- }
-
- real = ovl_dentry_lower(dentry);
- if (!real)
- goto bug;
/* Handle recursion */
- real = d_real(real, inode, open_flags);
+ if (unlikely(real->d_flags & DCACHE_OP_REAL))
+ return real->d_op->d_real(real, inode);
- if (!inode || inode == d_inode(real))
- return real;
bug:
WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry,
inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0);
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 129ef05759a9..712cc21c2e6d 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -147,8 +147,7 @@ struct dentry_operations {
char *(*d_dname)(struct dentry *, char *, int);
struct vfsmount *(*d_automount)(struct path *);
int (*d_manage)(const struct path *, bool);
- struct dentry *(*d_real)(struct dentry *, const struct inode *,
- unsigned int);
+ struct dentry *(*d_real)(struct dentry *, const struct inode *);
} ____cacheline_aligned;
/*
@@ -565,27 +564,6 @@ static inline struct dentry *d_backing_dentry(struct dentry *upper)
return 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
- *
- * If dentry is on a union/overlay, then return the underlying, real dentry.
- * Otherwise return the dentry itself.
- *
- * See also: Documentation/filesystems/vfs.txt
- */
-static inline struct dentry *d_real(struct dentry *dentry,
- const struct inode *inode,
- unsigned int flags)
-{
- if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
- return dentry->d_op->d_real(dentry, inode, flags);
- else
- return dentry;
-}
-
struct name_snapshot {
const unsigned char *name;
unsigned char inline_name[DNAME_INLINE_LEN];
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6db6e83004d6..77403c19dc69 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1234,7 +1234,12 @@ 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);
+ struct dentry *dentry = file->f_path.dentry;
+
+ if (unlikely(dentry->d_flags & DCACHE_OP_REAL))
+ return dentry->d_op->d_real(dentry, file_inode(file));
+ else
+ return dentry;
}
static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl)
--
2.14.3
next prev parent reply other threads:[~2018-04-12 15:10 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-12 15:07 [RFC PATCH 00/35] overlayfs: stack file operations Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 01/35] vfs: clean up dedup Miklos Szeredi
2018-04-12 16:25 ` Matthew Wilcox
2018-04-12 17:24 ` Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 02/35] vfs: add path_open() Miklos Szeredi
2018-04-12 16:38 ` Matthew Wilcox
2018-04-12 15:07 ` [RFC PATCH 03/35] vfs: optionally don't account file in nr_files Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 04/35] ovl: copy up times Miklos Szeredi
2018-04-13 8:25 ` Amir Goldstein
2018-04-13 14:23 ` Vivek Goyal
2018-04-12 15:07 ` [RFC PATCH 05/35] ovl: copy up inode flags Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 06/35] Revert "Revert "ovl: get_write_access() in truncate"" Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 07/35] ovl: copy up file size as well Miklos Szeredi
2018-04-24 18:10 ` Vivek Goyal
2018-04-12 15:07 ` [RFC PATCH 08/35] ovl: deal with overlay files in ovl_d_real() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 09/35] ovl: stack file ops Miklos Szeredi
2018-04-26 14:13 ` Vivek Goyal
2018-04-26 14:43 ` Miklos Szeredi
2018-04-26 14:56 ` Vivek Goyal
2018-04-26 15:01 ` Miklos Szeredi
2018-04-26 15:13 ` Vivek Goyal
2018-04-26 15:21 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 10/35] ovl: add helper to return real file Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 11/35] ovl: readd read_iter Miklos Szeredi
2018-04-13 13:35 ` Amir Goldstein
2018-04-12 15:08 ` [RFC PATCH 12/35] ovl: readd write_iter Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 13/35] ovl: readd fsync Miklos Szeredi
2018-04-23 13:36 ` Vivek Goyal
2018-04-23 13:39 ` Miklos Szeredi
2018-04-23 13:53 ` Vivek Goyal
2018-04-23 14:09 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 14/35] ovl: readd mmap Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 15/35] ovl: readd fallocate Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 16/35] ovl: readd lsattr/chattr support Miklos Szeredi
2018-04-13 14:48 ` Amir Goldstein
2018-04-17 19:51 ` Amir Goldstein
2018-04-22 8:35 ` Amir Goldstein
2018-04-22 15:18 ` Amir Goldstein
2018-04-23 10:21 ` Miklos Szeredi
2018-04-23 10:28 ` Miklos Szeredi
2018-04-23 6:11 ` Ritesh Harjani
2018-04-12 15:08 ` [RFC PATCH 17/35] ovl: readd fiemap Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 18/35] ovl: readd O_DIRECT support Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 19/35] ovl: readd reflink/copyfile/dedup support Miklos Szeredi
2018-04-17 20:31 ` Amir Goldstein
2018-04-18 8:39 ` Amir Goldstein
2018-05-03 16:04 ` Miklos Szeredi
2018-05-03 19:48 ` Amir Goldstein
2018-04-12 15:08 ` [RFC PATCH 20/35] vfs: don't open real Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 21/35] vfs: add f_op->pre_mmap() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 22/35] ovl: copy-up on MAP_SHARED Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 23/35] vfs: simplify dentry_open() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 24/35] Revert "ovl: fix relatime for directories" Miklos Szeredi
2018-04-13 14:02 ` Amir Goldstein
2018-04-13 15:55 ` Vivek Goyal
2018-04-12 15:08 ` [RFC PATCH 25/35] Revert "vfs: update ovl inode before relatime check" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 26/35] Revert "ovl: fix may_write_real() for overlayfs directories" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 27/35] Revert "ovl: don't allow writing ioctl on lower layer" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 28/35] Revert "vfs: add flags to d_real()" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 29/35] Revert "vfs: do get_write_access() on upper layer of overlayfs" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 30/35] Revert "vfs: make argument of d_real_inode() const" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 31/35] Revert "vfs: add d_real_inode() helper" Miklos Szeredi
2018-04-18 8:19 ` Amir Goldstein
2018-04-18 11:42 ` Miklos Szeredi
2018-04-18 13:38 ` Steven Rostedt
2018-04-18 13:49 ` Miklos Szeredi
2018-04-18 13:56 ` Steven Rostedt
2018-04-19 19:54 ` Vivek Goyal
2018-04-20 9:14 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 32/35] Partially revert "locks: fix file locking on overlayfs" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 33/35] Revert "fsnotify: support overlayfs" Miklos Szeredi
2018-04-12 15:08 ` Miklos Szeredi [this message]
2018-04-12 15:08 ` [RFC PATCH 35/35] ovl: fix documentation of non-standard behavior Miklos Szeredi
2018-04-13 11:23 ` Amir Goldstein
2018-04-25 14:49 ` [RFC PATCH 00/35] overlayfs: stack file operations J. R. Okajima
2018-04-25 19:44 ` Miklos Szeredi
2018-05-04 15:23 ` Miklos Szeredi
2018-05-05 16:37 ` Amir Goldstein
2018-05-08 14:25 ` Miklos Szeredi
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