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Subject[PATCH 13/16] ceph: implement i_op->atomic_open() and i_op->atomic_create()
Date
From: Miklos Szeredi <mszeredi@suse.cz>

Instead of calling ceph_lookup_open() from ->lookup and ->create, call it from
->atomic_open and ->atomic_create.

CEPH does non-create open in ->atomic_open and create-open in ->atomic_create.
To prevent unnecessary call to ->atomic_open the FS_NO_LOOKUP_CREATE flag is set
in the filesystem flags to only call ->atomic_open on non-create opens.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
---
fs/ceph/dir.c | 68 ++++++++++++++++++++++++++++++++++--------------------
fs/ceph/file.c | 21 ++++++++---------
fs/ceph/super.h | 5 ++-
3 files changed, 56 insertions(+), 38 deletions(-)
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index c4b7832..75df600 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -594,14 +594,6 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
if (err < 0)
return ERR_PTR(err);

- /* open (but not create!) intent? */
- if (nd &&
- (nd->flags & LOOKUP_OPEN) &&
- !(nd->intent.open.flags & O_CREAT)) {
- int mode = nd->intent.open.create_mode & ~current->fs->umask;
- return ceph_lookup_open(dir, dentry, nd, mode);
- }
-
/* can we conclude ENOENT locally? */
if (dentry->d_inode == NULL) {
struct ceph_inode_info *ci = ceph_inode(dir);
@@ -642,6 +634,47 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
return dentry;
}

+struct file *ceph_atomic_open(struct inode *dir, struct dentry *dentry,
+ struct opendata *od, unsigned flags, umode_t mode,
+ bool *created)
+{
+ int err;
+ struct dentry *res = NULL;
+ struct file *filp;
+
+ if (!(flags & O_CREAT)) {
+ if (dentry->d_name.len > NAME_MAX)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ err = ceph_init_dentry(dentry);
+ if (err < 0)
+ return ERR_PTR(err);
+
+ return ceph_lookup_open(dir, dentry, od, flags, mode);
+ }
+
+ if (d_unhashed(dentry)) {
+ res = ceph_lookup(dir, dentry, NULL);
+ if (IS_ERR(res))
+ return ERR_CAST(res);
+
+ if (res)
+ dentry = res;
+ }
+
+ /* We don't deal with positive dentries here */
+ if (dentry->d_inode) {
+ finish_no_open(od, res);
+ return NULL;
+ }
+
+ *created = true;
+ filp = ceph_lookup_open(dir, dentry, od, flags, mode);
+ dput(res);
+
+ return filp;
+}
+
/*
* If we do a create but get no trace back from the MDS, follow up with
* a lookup (the VFS expects us to link up the provided dentry).
@@ -702,23 +735,7 @@ static int ceph_mknod(struct inode *dir, struct dentry *dentry,
static int ceph_create(struct inode *dir, struct dentry *dentry, umode_t mode,
struct nameidata *nd)
{
- dout("create in dir %p dentry %p name '%.*s'\n",
- dir, dentry, dentry->d_name.len, dentry->d_name.name);
-
- if (ceph_snap(dir) != CEPH_NOSNAP)
- return -EROFS;
-
- if (nd) {
- BUG_ON((nd->flags & LOOKUP_OPEN) == 0);
- dentry = ceph_lookup_open(dir, dentry, nd, mode);
- /* hrm, what should i do here if we get aliased? */
- if (IS_ERR(dentry))
- return PTR_ERR(dentry);
- return 0;
- }
-
- /* fall back to mknod */
- return ceph_mknod(dir, dentry, (mode & ~S_IFMT) | S_IFREG, 0);
+ return ceph_mknod(dir, dentry, mode, 0);
}

static int ceph_symlink(struct inode *dir, struct dentry *dentry,
@@ -1357,6 +1374,7 @@ const struct inode_operations ceph_dir_iops = {
.rmdir = ceph_unlink,
.rename = ceph_rename,
.create = ceph_create,
+ .atomic_open = ceph_atomic_open,
};

const struct dentry_operations ceph_dentry_ops = {
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 2fe9a3e..bf35158 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -214,21 +214,15 @@ out:
* may_open() fails, the struct *file gets cleaned up (i.e.
* ceph_release gets called). So fear not!
*/
-/*
- * flags
- * path_lookup_open -> LOOKUP_OPEN
- * path_lookup_create -> LOOKUP_OPEN|LOOKUP_CREATE
- */
-struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd, int mode)
+struct file *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+ struct opendata *od, unsigned flags, umode_t mode)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
struct ceph_mds_client *mdsc = fsc->mdsc;
- struct file *file;
+ struct file *file = NULL;
struct ceph_mds_request *req;
struct dentry *ret;
int err;
- int flags = nd->intent.open.flags;

dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);
@@ -254,14 +248,19 @@ struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
err = ceph_handle_notrace_create(dir, dentry);
if (err)
goto out;
- file = lookup_instantiate_filp(nd, req->r_dentry, ceph_open);
+ file = finish_open(od, req->r_dentry, ceph_open);
if (IS_ERR(file))
err = PTR_ERR(file);
out:
ret = ceph_finish_lookup(req, dentry, err);
ceph_mdsc_put_request(req);
dout("ceph_lookup_open result=%p\n", ret);
- return ret;
+
+ if (IS_ERR(ret))
+ return ERR_CAST(ret);
+
+ dput(ret);
+ return err ? ERR_PTR(err) : file;
}

int ceph_release(struct inode *inode, struct file *file)
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index c6b2cba..4e83114 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -804,8 +804,9 @@ extern int ceph_copy_from_page_vector(struct page **pages,
loff_t off, size_t len);
extern struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags);
extern int ceph_open(struct inode *inode, struct file *file);
-extern struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
- struct nameidata *nd, int mode);
+extern struct file *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+ struct opendata *od, unsigned flags,
+ umode_t mode);
extern int ceph_release(struct inode *inode, struct file *filp);

/* dir.c */
--
1.7.7


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