ceph: simplify+fix atomic_open
The initial ->atomic_open op was carried over from the old intent code,
which was incomplete and didn't really work. Replace it with a fresh
method. In particular:
* always attempt to do an atomic open+lookup, both for the create case
and for lookups of existing files.
* fix symlink handling by returning 1 to the VFS so that we can follow
the link to its destination. This fixes a longstanding ceph bug (#2392).
Signed-off-by: Sage Weil <sage@inktank.com>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 1b81d6c..ecebbc0 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -4,6 +4,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/file.h>
+#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/writeback.h>
@@ -106,9 +107,6 @@
}
/*
- * If the filp already has private_data, that means the file was
- * already opened by intent during lookup, and we do nothing.
- *
* If we already have the requisite capabilities, we can satisfy
* the open request locally (no need to request new caps from the
* MDS). We do, however, need to inform the MDS (asynchronously)
@@ -207,24 +205,29 @@
/*
- * Do a lookup + open with a single request.
- *
- * If this succeeds, but some subsequent check in the vfs
- * may_open() fails, the struct *file gets cleaned up (i.e.
- * ceph_release gets called). So fear not!
+ * Do a lookup + open with a single request. If we get a non-existent
+ * file or symlink, return 1 so the VFS can retry.
*/
-int ceph_lookup_open(struct inode *dir, struct dentry *dentry,
+int ceph_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, unsigned flags, umode_t mode,
int *opened)
{
struct ceph_fs_client *fsc = ceph_sb_to_client(dir->i_sb);
struct ceph_mds_client *mdsc = fsc->mdsc;
struct ceph_mds_request *req;
- struct dentry *ret;
+ struct dentry *dn;
int err;
- dout("ceph_lookup_open dentry %p '%.*s' flags %d mode 0%o\n",
- dentry, dentry->d_name.len, dentry->d_name.name, flags, mode);
+ dout("atomic_open %p dentry %p '%.*s' %s flags %d mode 0%o\n",
+ dir, dentry, dentry->d_name.len, dentry->d_name.name,
+ d_unhashed(dentry) ? "unhashed" : "hashed", flags, mode);
+
+ if (dentry->d_name.len > NAME_MAX)
+ return -ENAMETOOLONG;
+
+ err = ceph_init_dentry(dentry);
+ if (err < 0)
+ return err;
/* do the open */
req = prepare_open_request(dir->i_sb, flags, mode);
@@ -241,22 +244,31 @@
(flags & (O_CREAT|O_TRUNC)) ? dir : NULL,
req);
err = ceph_handle_snapdir(req, dentry, err);
- if (err)
- goto out;
- if ((flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
+ if (err == 0 && (flags & O_CREAT) && !req->r_reply_info.head->is_dentry)
err = ceph_handle_notrace_create(dir, dentry);
+
+ if (d_unhashed(dentry)) {
+ dn = ceph_finish_lookup(req, dentry, err);
+ if (IS_ERR(dn))
+ err = PTR_ERR(dn);
+ } else {
+ /* we were given a hashed negative dentry */
+ dn = NULL;
+ }
if (err)
- goto out;
- err = finish_open(file, req->r_dentry, ceph_open, opened);
-out:
- ret = ceph_finish_lookup(req, dentry, err);
+ goto out_err;
+ if (dn || dentry->d_inode == NULL || S_ISLNK(dentry->d_inode->i_mode)) {
+ /* make vfs retry on splice, ENOENT, or symlink */
+ dout("atomic_open finish_no_open on dn %p\n", dn);
+ err = finish_no_open(file, dn);
+ } else {
+ dout("atomic_open finish_open on dn %p\n", dn);
+ err = finish_open(file, dentry, ceph_open, opened);
+ }
+
+out_err:
ceph_mdsc_put_request(req);
- dout("ceph_lookup_open result=%p\n", ret);
-
- if (IS_ERR(ret))
- return PTR_ERR(ret);
-
- dput(ret);
+ dout("atomic_open result=%d\n", err);
return err;
}