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ceph: fix ceph_lookup_open intent usage

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We weren't properly calling lookup_instantiate_filp when setting up the
lookup intent, which could lead to file leakage on errors.  So:

 - use separate helper for the hidden snapdir translation, immediately
   following the mds request
 - use ceph_finish_lookup for the final dentry/return value dance in the
   exit path
 - lookup_instantiate_filp on success

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
This commit is contained in:
Sage Weil 2011-07-26 11:28:11 -07:00
parent 9bae113a08
commit 468640e32c
3 changed files with 37 additions and 19 deletions
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31
fs/ceph/dir.c
View file

@ -482,18 +482,10 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int origin)
}
/*
* Process result of a lookup/open request.
*
* Mainly, make sure we return the final req->r_dentry (if it already
* existed) in place of the original VFS-provided dentry when they
* differ.
*
* Gracefully handle the case where the MDS replies with -ENOENT and
* no trace (which it may do, at its discretion, e.g., if it doesn't
* care to issue a lease on the negative dentry).
* Handle lookups for the hidden .snap directory.
*/
struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
struct dentry *dentry, int err)
int ceph_handle_snapdir(struct ceph_mds_request *req,
struct dentry *dentry, int err)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dentry->d_sb);
struct inode *parent = dentry->d_parent->d_inode;
@ -510,7 +502,23 @@ struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
d_add(dentry, inode);
err = 0;
}
return err;
}
/*
* Figure out final result of a lookup/open request.
*
* Mainly, make sure we return the final req->r_dentry (if it already
* existed) in place of the original VFS-provided dentry when they
* differ.
*
* Gracefully handle the case where the MDS replies with -ENOENT and
* no trace (which it may do, at its discretion, e.g., if it doesn't
* care to issue a lease on the negative dentry).
*/
struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
struct dentry *dentry, int err)
{
if (err == -ENOENT) {
/* no trace? */
err = 0;
@ -605,6 +613,7 @@ static struct dentry *ceph_lookup(struct inode *dir, struct dentry *dentry,
req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
req->r_locked_dir = dir;
err = ceph_mdsc_do_request(mdsc, NULL, req);
err = ceph_handle_snapdir(req, dentry, err);
dentry = ceph_finish_lookup(req, dentry, err);
ceph_mdsc_put_request(req); /* will dput(dentry) */
dout("lookup result=%p\n", dentry);

23
fs/ceph/file.c
View file

@ -223,8 +223,9 @@ struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
struct ceph_mds_client *mdsc = fsc->mdsc;
struct file *file = nd->intent.open.file;
struct file *file;
struct ceph_mds_request *req;
struct dentry *ret;
int err;
int flags = nd->intent.open.flags - 1; /* silly vfs! */
@ -245,15 +246,21 @@ struct dentry *ceph_lookup_open(struct inode *dir, struct dentry *dentry,
err = ceph_mdsc_do_request(mdsc,
(flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
req);
dentry = ceph_finish_lookup(req, dentry, err);
if (!err && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
err = ceph_handle_snapdir(req, dentry, err);
if (err)
goto out;
if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
err = ceph_handle_notrace_create(dir, dentry);
if (!err)
err = ceph_init_file(req->r_dentry->d_inode, file,
req->r_fmode);
if (err)
goto out;
file = lookup_instantiate_filp(nd, 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", dentry);
return dentry;
dout("ceph_lookup_open result=%p\n", ret);
return ret;
}
int ceph_release(struct inode *inode, struct file *file)

2
fs/ceph/super.h
View file

@ -791,6 +791,8 @@ extern const struct dentry_operations ceph_dentry_ops, ceph_snap_dentry_ops,
ceph_snapdir_dentry_ops;
extern int ceph_handle_notrace_create(struct inode *dir, struct dentry *dentry);
extern int ceph_handle_snapdir(struct ceph_mds_request *req,
struct dentry *dentry, int err);
extern struct dentry *ceph_finish_lookup(struct ceph_mds_request *req,
struct dentry *dentry, int err);