From: Miklos Szeredi <miklos@szeredi.hu>
To: viro@ZenIV.linux.org.uk, torvalds@linux-foundation.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
hch@infradead.org, akpm@linux-foundation.org, apw@canonical.com,
nbd@openwrt.org, neilb@suse.de, jordipujolp@gmail.com,
ezk@fsl.cs.sunysb.edu, dhowells@redhat.com,
sedat.dilek@gmail.com, hooanon05@yahoo.co.jp, mszeredi@suse.cz
Subject: [PATCH 01/13] vfs: add i_op->dentry_open()
Date: Fri, 23 May 2014 11:43:31 +0200 [thread overview]
Message-ID: <1400838223-30844-2-git-send-email-miklos@szeredi.hu> (raw)
In-Reply-To: <1400838223-30844-1-git-send-email-miklos@szeredi.hu>
From: Miklos Szeredi <mszeredi@suse.cz>
Add a new inode operation i_op->dentry_open(). This is for stacked filesystems
that want to return a struct file from a different filesystem.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
Documentation/filesystems/Locking | 2 ++
Documentation/filesystems/vfs.txt | 7 +++++++
fs/namei.c | 9 ++++++---
fs/open.c | 23 +++++++++++++++++++++--
include/linux/fs.h | 2 ++
5 files changed, 38 insertions(+), 5 deletions(-)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index eba790134253..09a7b57d2f47 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -67,6 +67,7 @@ prototypes:
struct file *, unsigned open_flag,
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+ int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
locking rules:
all may block
@@ -96,6 +97,7 @@ fiemap: no
update_time: no
atomic_open: yes
tmpfile: no
+dentry_open: no
Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
victim.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 617f6d70c077..938aea64b2fa 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -364,6 +364,7 @@ struct inode_operations {
int (*atomic_open)(struct inode *, struct dentry *, struct file *,
unsigned open_flag, umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
+ int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
};
Again, all methods are called without any locks being held, unless
@@ -697,6 +698,12 @@ struct address_space_operations {
but instead uses bmap to find out where the blocks in the file
are and uses those addresses directly.
+ dentry_open: this is an alternative to f_op->open(), the difference is that
+ this method may open a file not necessarily originating from the same
+ filesystem as the one i_op->open() was called on. It may be
+ useful for stacking filesystems which want to allow native I/O directly
+ on underlying files.
+
invalidatepage: If a page has PagePrivate set, then invalidatepage
will be called when part or all of the page is to be removed
diff --git a/fs/namei.c b/fs/namei.c
index 80168273396b..a7cf0fb1f638 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3046,9 +3046,12 @@ finish_open_created:
error = may_open(&nd->path, acc_mode, open_flag);
if (error)
goto out;
- file->f_path.mnt = nd->path.mnt;
- error = finish_open(file, nd->path.dentry, NULL, opened);
- if (error) {
+
+ BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
+ error = vfs_open(&nd->path, file, current_cred());
+ if (!error) {
+ *opened |= FILE_OPENED;
+ } else {
if (error == -EOPENSTALE)
goto stale_open;
goto out;
diff --git a/fs/open.c b/fs/open.c
index 9d64679cec73..3302cd25403f 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -818,8 +818,7 @@ struct file *dentry_open(const struct path *path, int flags,
f = get_empty_filp();
if (!IS_ERR(f)) {
f->f_flags = flags;
- f->f_path = *path;
- error = do_dentry_open(f, NULL, cred);
+ error = vfs_open(path, f, cred);
if (!error) {
/* from now on we need fput() to dispose of f */
error = open_check_o_direct(f);
@@ -836,6 +835,26 @@ struct file *dentry_open(const struct path *path, int flags,
}
EXPORT_SYMBOL(dentry_open);
+/**
+ * vfs_open - open the file at the given path
+ * @path: path to open
+ * @filp: newly allocated file with f_flag initialized
+ * @cred: credentials to use
+ */
+int vfs_open(const struct path *path, struct file *filp,
+ const struct cred *cred)
+{
+ struct inode *inode = path->dentry->d_inode;
+
+ if (inode->i_op->dentry_open)
+ return inode->i_op->dentry_open(path->dentry, filp, cred);
+ else {
+ filp->f_path = *path;
+ return do_dentry_open(filp, NULL, cred);
+ }
+}
+EXPORT_SYMBOL(vfs_open);
+
static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
{
int lookup_flags = 0;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 878031227c57..d38875d70db2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1513,6 +1513,7 @@ struct inode_operations {
umode_t create_mode, int *opened);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
int (*set_acl)(struct inode *, struct posix_acl *, int);
+ int (*dentry_open)(struct dentry *, struct file *, const struct cred *);
} ____cacheline_aligned;
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
@@ -2018,6 +2019,7 @@ extern struct file *file_open_name(struct filename *, int, umode_t);
extern struct file *filp_open(const char *, int, umode_t);
extern struct file *file_open_root(struct dentry *, struct vfsmount *,
const char *, int);
+extern int vfs_open(const struct path *, struct file *, const struct cred *);
extern struct file * dentry_open(const struct path *, int, const struct cred *);
extern int filp_close(struct file *, fl_owner_t id);
--
1.8.1.4
next prev parent reply other threads:[~2014-05-23 9:48 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-23 9:43 [PATCH 00/13] overlay filesystem v22 Miklos Szeredi
2014-05-23 9:43 ` Miklos Szeredi [this message]
2014-05-23 9:43 ` [PATCH 02/13] vfs: export do_splice_direct() to modules Miklos Szeredi
2014-05-23 9:43 ` [PATCH 03/13] vfs: export __inode_permission() " Miklos Szeredi
2014-05-23 9:43 ` [PATCH 04/13] vfs: introduce clone_private_mount() Miklos Szeredi
2014-05-23 9:43 ` [PATCH 05/13] vfs: export check_sticky() Miklos Szeredi
2014-05-23 9:43 ` [PATCH 06/13] vfs: add whiteout support Miklos Szeredi
2014-05-24 8:29 ` Tetsuo Handa
2014-05-23 9:43 ` [PATCH 07/13] vfs: add RENAME_WHITEOUT Miklos Szeredi
2014-05-24 8:02 ` Azat Khuzhin
2014-05-23 9:43 ` [PATCH 08/13] overlay filesystem Miklos Szeredi
2014-05-23 9:43 ` [PATCH 09/13] overlayfs: add statfs support Miklos Szeredi
2014-05-23 9:43 ` [PATCH 10/13] overlayfs: implement show_options Miklos Szeredi
2014-05-23 9:43 ` [PATCH 11/13] overlay: overlay filesystem documentation Miklos Szeredi
2014-05-23 9:43 ` [PATCH 12/13] fs: limit filesystem stacking depth Miklos Szeredi
2014-05-23 9:43 ` [PATCH 13/13] vfs: dcache: Export d_ancestor to modules Miklos Szeredi
2014-05-26 1:56 ` [PATCH 00/13] overlay filesystem v22 J. R. Okajima
2014-05-28 16:06 ` Miklos Szeredi
2014-05-29 10:26 ` David Howells
2014-05-29 11:26 ` Miklos Szeredi
2014-05-29 10:54 ` Kernel errors with " David Howells
2014-05-29 11:16 ` David Howells
2014-05-29 11:28 ` David Howells
2014-05-29 12:07 ` Miklos Szeredi
2014-05-29 16:06 ` Miklos Szeredi
2014-05-29 16:10 ` Sedat Dilek
2014-05-29 16:23 ` More kernel " David Howells
2014-05-29 16:36 ` Miklos Szeredi
2014-05-29 16:44 ` David Howells
2014-05-29 16:48 ` Unionmount and overlayfs testsuite David Howells
2014-05-29 17:11 ` Sedat Dilek
2014-05-29 17:15 ` David Howells
2014-05-29 17:19 ` Sedat Dilek
2014-05-29 17:24 ` David Howells
2014-05-29 17:36 ` Sedat Dilek
2014-05-29 17:41 ` David Howells
2014-05-29 17:44 ` Sedat Dilek
2014-05-29 18:22 ` David Howells
2014-05-29 18:44 ` Sedat Dilek
2014-05-29 18:53 ` Sedat Dilek
2014-05-29 19:20 ` David Howells
2014-05-29 19:24 ` Sedat Dilek
2014-05-29 19:25 ` David Howells
2014-05-29 19:28 ` Sedat Dilek
2014-05-29 19:35 ` David Howells
2014-05-29 20:00 ` Sedat Dilek
2014-05-29 20:59 ` David Howells
2014-05-30 4:15 ` Sedat Dilek
2014-05-30 4:29 ` Sedat Dilek
2014-05-30 7:54 ` David Howells
2014-05-29 17:35 ` Sedat Dilek
2014-05-29 17:50 ` David Howells
2014-05-29 17:58 ` Sedat Dilek
2014-05-29 18:23 ` Dave Jones
2014-05-29 18:27 ` David Howells
2014-05-29 17:17 ` David Howells
2014-05-29 23:21 ` Dave Chinner
2014-05-30 3:35 ` J. R. Okajima
2014-05-30 4:44 ` J. R. Okajima
2014-05-30 8:49 ` David Howells
2014-05-30 9:15 ` J. R. Okajima
2014-06-03 8:08 ` Sedat Dilek
2014-06-03 9:00 ` David Howells
2014-06-03 9:12 ` Miklos Szeredi
2014-06-03 9:18 ` Sedat Dilek
2014-06-03 9:26 ` Sedat Dilek
2014-06-03 9:39 ` Sedat Dilek
2014-06-03 9:42 ` Miklos Szeredi
2014-06-03 10:15 ` Sedat Dilek
2014-06-03 10:21 ` Sedat Dilek
2014-06-03 10:55 ` Sedat Dilek
2014-06-03 10:33 ` David Howells
2014-06-03 13:21 ` Miklos Szeredi
2014-06-03 14:26 ` Sedat Dilek
2014-06-03 15:30 ` David Howells
2014-06-03 15:53 ` Miklos Szeredi
2014-06-05 22:16 ` David Howells
2014-06-24 16:46 ` Overlayfs rename bug David Howells
2014-07-08 9:29 ` Miklos Szeredi
2014-07-08 9:56 ` David Howells
2014-07-09 14:14 ` Miklos Szeredi
2014-05-30 9:14 ` Unionmount and overlayfs testsuite David Howells
2014-05-29 17:29 ` Kernel errors with overlay filesystem v22 David Howells
-- strict thread matches above, loose matches on Subject: below --
2012-09-20 18:55 [PATCH 00/13] overlay filesystem: request for inclusion (v15) Miklos Szeredi
2012-09-20 18:55 ` [PATCH 01/13] vfs: add i_op->dentry_open() Miklos Szeredi
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