Commit b48dbb99 authored by Dominique Martinet's avatar Dominique Martinet Committed by Dominique Martinet

9p fid refcount: add p9_fid_get/put wrappers

I was recently reminded that it is not clear that p9_client_clunk()
was actually just decrementing refcount and clunking only when that
reaches zero: make it clear through a set of helpers.

This will also allow instrumenting refcounting better for debugging
next patch

Link: https://lkml.kernel.org/r/20220612085330.1451496-5-asmadeus@codewreck.orgReviewed-by: default avatarTyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: default avatarChristian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: default avatarDominique Martinet <asmadeus@codewreck.org>
parent b296d057
......@@ -56,7 +56,7 @@ static struct p9_fid *v9fs_fid_find_inode(struct inode *inode, kuid_t uid)
h = (struct hlist_head *)&inode->i_private;
hlist_for_each_entry(fid, h, ilist) {
if (uid_eq(fid->uid, uid)) {
refcount_inc(&fid->count);
p9_fid_get(fid);
ret = fid;
break;
}
......@@ -104,7 +104,7 @@ static struct p9_fid *v9fs_fid_find(struct dentry *dentry, kuid_t uid, int any)
hlist_for_each_entry(fid, h, dlist) {
if (any || uid_eq(fid->uid, uid)) {
ret = fid;
refcount_inc(&ret->count);
p9_fid_get(ret);
break;
}
}
......@@ -172,7 +172,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
old_fid = fid;
fid = p9_client_walk(old_fid, 1, &dentry->d_name.name, 1);
p9_client_clunk(old_fid);
p9_fid_put(old_fid);
goto fid_out;
}
up_read(&v9ses->rename_sem);
......@@ -194,7 +194,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
if (IS_ERR(root_fid))
return root_fid;
refcount_inc(&root_fid->count);
p9_fid_get(root_fid);
v9fs_fid_add(dentry->d_sb->s_root, root_fid);
}
/* If we are root ourself just return that */
......@@ -225,7 +225,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
old_fid == root_fid /* clone */);
/* non-cloning walk will return the same fid */
if (fid != old_fid) {
p9_client_clunk(old_fid);
p9_fid_put(old_fid);
old_fid = fid;
}
if (IS_ERR(fid)) {
......@@ -240,11 +240,11 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct dentry *dentry,
spin_lock(&dentry->d_lock);
if (d_unhashed(dentry)) {
spin_unlock(&dentry->d_lock);
p9_client_clunk(fid);
p9_fid_put(fid);
fid = ERR_PTR(-ENOENT);
} else {
__add_fid(dentry, fid);
refcount_inc(&fid->count);
p9_fid_get(fid);
spin_unlock(&dentry->d_lock);
}
}
......@@ -301,7 +301,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
fid = clone_fid(ofid);
if (IS_ERR(fid))
goto error_out;
p9_client_clunk(ofid);
p9_fid_put(ofid);
/*
* writeback fid will only be used to write back the
* dirty pages. We always request for the open fid in read-write
......@@ -310,7 +310,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
*/
err = p9_client_open(fid, O_RDWR);
if (err < 0) {
p9_client_clunk(fid);
p9_fid_put(fid);
fid = ERR_PTR(err);
goto error_out;
}
......
......@@ -29,7 +29,7 @@ static inline struct p9_fid *v9fs_fid_clone(struct dentry *dentry)
return fid;
nfid = clone_fid(fid);
p9_client_clunk(fid);
p9_fid_put(fid);
return nfid;
}
#endif
......@@ -73,7 +73,7 @@ static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
BUG_ON(!fid);
}
refcount_inc(&fid->count);
p9_fid_get(fid);
rreq->netfs_priv = fid;
return 0;
}
......@@ -86,7 +86,7 @@ static void v9fs_free_request(struct netfs_io_request *rreq)
{
struct p9_fid *fid = rreq->netfs_priv;
p9_client_clunk(fid);
p9_fid_put(fid);
}
/**
......
......@@ -54,7 +54,7 @@ static void v9fs_dentry_release(struct dentry *dentry)
p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
dentry, dentry);
hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
dentry->d_fsdata = NULL;
}
......@@ -85,7 +85,7 @@ static int v9fs_lookup_revalidate(struct dentry *dentry, unsigned int flags)
retval = v9fs_refresh_inode_dotl(fid, inode);
else
retval = v9fs_refresh_inode(fid, inode);
p9_client_clunk(fid);
p9_fid_put(fid);
if (retval == -ENOENT)
return 0;
......
......@@ -218,7 +218,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
spin_lock(&inode->i_lock);
hlist_del(&fid->ilist);
spin_unlock(&inode->i_lock);
p9_client_clunk(fid);
p9_fid_put(fid);
}
if ((filp->f_mode & FMODE_WRITE)) {
......
......@@ -63,7 +63,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
err = p9_client_open(fid, omode);
if (err < 0) {
p9_client_clunk(fid);
p9_fid_put(fid);
return err;
}
if ((file->f_flags & O_APPEND) &&
......@@ -98,7 +98,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
v9fs_open_fid_add(inode, fid);
return 0;
out_error:
p9_client_clunk(file->private_data);
p9_fid_put(file->private_data);
file->private_data = NULL;
return err;
}
......
......@@ -400,7 +400,7 @@ void v9fs_evict_inode(struct inode *inode)
fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
/* clunk the fid stashed in writeback_fid */
if (v9inode->writeback_fid) {
p9_client_clunk(v9inode->writeback_fid);
p9_fid_put(v9inode->writeback_fid);
v9inode->writeback_fid = NULL;
}
}
......@@ -569,7 +569,7 @@ static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
if (v9fs_proto_dotl(v9ses))
retval = p9_client_unlinkat(dfid, dentry->d_name.name,
v9fs_at_to_dotl_flags(flags));
p9_client_clunk(dfid);
p9_fid_put(dfid);
if (retval == -EOPNOTSUPP) {
/* Try the one based on path */
v9fid = v9fs_fid_clone(dentry);
......@@ -633,14 +633,14 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
if (IS_ERR(ofid)) {
err = PTR_ERR(ofid);
p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
return ERR_PTR(err);
}
err = p9_client_fcreate(ofid, name, perm, mode, extension);
if (err < 0) {
p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto error;
}
......@@ -652,7 +652,7 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
p9_debug(P9_DEBUG_VFS,
"p9_client_walk failed %d\n", err);
fid = NULL;
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto error;
}
/*
......@@ -663,20 +663,20 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
err = PTR_ERR(inode);
p9_debug(P9_DEBUG_VFS,
"inode creation failed %d\n", err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto error;
}
v9fs_fid_add(dentry, fid);
d_instantiate(dentry, inode);
}
p9_client_clunk(dfid);
p9_fid_put(dfid);
return ofid;
error:
if (ofid)
p9_client_clunk(ofid);
p9_fid_put(ofid);
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
return ERR_PTR(err);
}
......@@ -708,7 +708,7 @@ v9fs_vfs_create(struct user_namespace *mnt_userns, struct inode *dir,
return PTR_ERR(fid);
v9fs_invalidate_inode_attr(dir);
p9_client_clunk(fid);
p9_fid_put(fid);
return 0;
}
......@@ -744,7 +744,7 @@ static int v9fs_vfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
}
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
return err;
}
......@@ -785,7 +785,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
*/
name = dentry->d_name.name;
fid = p9_client_walk(dfid, 1, &name, 1);
p9_client_clunk(dfid);
p9_fid_put(dfid);
if (fid == ERR_PTR(-ENOENT))
inode = NULL;
else if (IS_ERR(fid))
......@@ -808,7 +808,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
else if (!IS_ERR(res))
v9fs_fid_add(res, fid);
else
p9_client_clunk(fid);
p9_fid_put(fid);
}
return res;
}
......@@ -891,7 +891,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
error:
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
goto out;
}
......@@ -959,7 +959,7 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
dfid = v9fs_parent_fid(old_dentry);
olddirfid = clone_fid(dfid);
if (dfid && !IS_ERR(dfid))
p9_client_clunk(dfid);
p9_fid_put(dfid);
if (IS_ERR(olddirfid)) {
retval = PTR_ERR(olddirfid);
......@@ -968,7 +968,7 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
dfid = v9fs_parent_fid(new_dentry);
newdirfid = clone_fid(dfid);
p9_client_clunk(dfid);
p9_fid_put(dfid);
if (IS_ERR(newdirfid)) {
retval = PTR_ERR(newdirfid);
......@@ -1020,13 +1020,13 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
d_move(old_dentry, new_dentry);
}
up_write(&v9ses->rename_sem);
p9_client_clunk(newdirfid);
p9_fid_put(newdirfid);
clunk_olddir:
p9_client_clunk(olddirfid);
p9_fid_put(olddirfid);
done:
p9_client_clunk(oldfid);
p9_fid_put(oldfid);
return retval;
}
......@@ -1060,7 +1060,7 @@ v9fs_vfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
return PTR_ERR(fid);
st = p9_client_stat(fid);
p9_client_clunk(fid);
p9_fid_put(fid);
if (IS_ERR(st))
return PTR_ERR(st);
......@@ -1136,7 +1136,7 @@ static int v9fs_vfs_setattr(struct user_namespace *mnt_userns,
retval = p9_client_wstat(fid, &wstat);
if (use_dentry)
p9_client_clunk(fid);
p9_fid_put(fid);
if (retval < 0)
return retval;
......@@ -1261,7 +1261,7 @@ static const char *v9fs_vfs_get_link(struct dentry *dentry,
return ERR_CAST(fid);
st = p9_client_stat(fid);
p9_client_clunk(fid);
p9_fid_put(fid);
if (IS_ERR(st))
return ERR_CAST(st);
......@@ -1308,7 +1308,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
return PTR_ERR(fid);
v9fs_invalidate_inode_attr(dir);
p9_client_clunk(fid);
p9_fid_put(fid);
return 0;
}
......@@ -1364,7 +1364,7 @@ v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
v9fs_refresh_inode(oldfid, d_inode(old_dentry));
v9fs_invalidate_inode_attr(dir);
}
p9_client_clunk(oldfid);
p9_fid_put(oldfid);
return retval;
}
......
......@@ -274,7 +274,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
if (IS_ERR(ofid)) {
err = PTR_ERR(ofid);
p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto out;
}
......@@ -286,7 +286,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
if (err) {
p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat %d\n",
err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto error;
}
err = p9_client_create_dotl(ofid, name, v9fs_open_to_dotl_flags(flags),
......@@ -294,14 +294,14 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
if (err < 0) {
p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in creat %d\n",
err);
p9_client_clunk(dfid);
p9_fid_put(dfid);
goto error;
}
v9fs_invalidate_inode_attr(dir);
/* instantiate inode and assign the unopened fid to the dentry */
fid = p9_client_walk(dfid, 1, &name, 1);
p9_client_clunk(dfid);
p9_fid_put(dfid);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
......@@ -358,10 +358,10 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
error:
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
err_clunk_old_fid:
if (ofid)
p9_client_clunk(ofid);
p9_fid_put(ofid);
goto out;
}
......@@ -458,9 +458,9 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace *mnt_userns,
v9fs_invalidate_inode_attr(dir);
error:
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
v9fs_put_acl(dacl, pacl);
p9_client_clunk(dfid);
p9_fid_put(dfid);
return err;
}
......@@ -489,7 +489,7 @@ v9fs_vfs_getattr_dotl(struct user_namespace *mnt_userns,
*/
st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
p9_client_clunk(fid);
p9_fid_put(fid);
if (IS_ERR(st))
return PTR_ERR(st);
......@@ -603,7 +603,7 @@ int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
retval = p9_client_setattr(fid, &p9attr);
if (retval < 0) {
if (use_dentry)
p9_client_clunk(fid);
p9_fid_put(fid);
return retval;
}
......@@ -619,12 +619,12 @@ int v9fs_vfs_setattr_dotl(struct user_namespace *mnt_userns,
retval = v9fs_acl_chmod(inode, fid);
if (retval < 0) {
if (use_dentry)
p9_client_clunk(fid);
p9_fid_put(fid);
return retval;
}
}
if (use_dentry)
p9_client_clunk(fid);
p9_fid_put(fid);
return 0;
}
......@@ -771,9 +771,9 @@ v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns, struct inode *dir,
error:
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
p9_client_clunk(dfid);
p9_fid_put(dfid);
return err;
}
......@@ -803,14 +803,14 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
oldfid = v9fs_fid_lookup(old_dentry);
if (IS_ERR(oldfid)) {
p9_client_clunk(dfid);
p9_fid_put(dfid);
return PTR_ERR(oldfid);
}
err = p9_client_link(dfid, oldfid, dentry->d_name.name);
p9_client_clunk(dfid);
p9_client_clunk(oldfid);
p9_fid_put(dfid);
p9_fid_put(oldfid);
if (err < 0) {
p9_debug(P9_DEBUG_VFS, "p9_client_link failed %d\n", err);
return err;
......@@ -826,7 +826,7 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct inode *dir,
return PTR_ERR(fid);
v9fs_refresh_inode_dotl(fid, d_inode(old_dentry));
p9_client_clunk(fid);
p9_fid_put(fid);
}
ihold(d_inode(old_dentry));
d_instantiate(dentry, d_inode(old_dentry));
......@@ -924,9 +924,9 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns, struct inode *dir,
}
error:
if (fid)
p9_client_clunk(fid);
p9_fid_put(fid);
v9fs_put_acl(dacl, pacl);
p9_client_clunk(dfid);
p9_fid_put(dfid);
return err;
}
......@@ -956,7 +956,7 @@ v9fs_vfs_get_link_dotl(struct dentry *dentry,
if (IS_ERR(fid))
return ERR_CAST(fid);
retval = p9_client_readlink(fid, &target);
p9_client_clunk(fid);
p9_fid_put(fid);
if (retval)
return ERR_PTR(retval);
set_delayed_call(done, kfree_link, target);
......
......@@ -190,7 +190,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
return dget(sb->s_root);
clunk_fid:
p9_client_clunk(fid);
p9_fid_put(fid);
v9fs_session_close(v9ses);
free_session:
kfree(v9ses);
......@@ -203,7 +203,7 @@ static struct dentry *v9fs_mount(struct file_system_type *fs_type, int flags,
* attached the fid to dentry so it won't get clunked
* automatically.
*/
p9_client_clunk(fid);
p9_fid_put(fid);
deactivate_locked_super(sb);
return ERR_PTR(retval);
}
......@@ -270,7 +270,7 @@ static int v9fs_statfs(struct dentry *dentry, struct kstatfs *buf)
}
res = simple_statfs(dentry, buf);
done:
p9_client_clunk(fid);
p9_fid_put(fid);
return res;
}
......
......@@ -44,7 +44,7 @@ ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
if (err)
retval = err;
}
p9_client_clunk(attr_fid);
p9_fid_put(attr_fid);
return retval;
}
......@@ -71,7 +71,7 @@ ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
if (IS_ERR(fid))
return PTR_ERR(fid);
ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
p9_client_clunk(fid);
p9_fid_put(fid);
return ret;
}
......@@ -98,7 +98,7 @@ int v9fs_xattr_set(struct dentry *dentry, const char *name,
if (IS_ERR(fid))
return PTR_ERR(fid);
ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
p9_client_clunk(fid);
p9_fid_put(fid);
return ret;
}
......@@ -128,7 +128,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char *name,
retval);
else
p9_client_write(fid, 0, &from, &retval);
err = p9_client_clunk(fid);
err = p9_fid_put(fid);
if (!retval && err)
retval = err;
return retval;
......
......@@ -237,6 +237,34 @@ static inline int p9_req_try_get(struct p9_req_t *r)
int p9_req_put(struct p9_req_t *r);
/* fid reference counting helpers:
* - fids used for any length of time should always be referenced through
* p9_fid_get(), and released with p9_fid_put()
* - v9fs_fid_lookup() or similar will automatically call get for you
* and also require a put
* - the *_fid_add() helpers will stash the fid in the inode,
* at which point it is the responsibility of evict_inode()
* to call the put
* - the last put will automatically send a clunk to the server
*/
static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
{
refcount_inc(&fid->count);
return fid;
}
static inline int p9_fid_put(struct p9_fid *fid)
{
if (!fid || IS_ERR(fid))
return 0;
if (!refcount_dec_and_test(&fid->count))
return 0;
return p9_client_clunk(fid);
}
void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
......
......@@ -1228,7 +1228,7 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
clunk_fid:
kfree(wqids);
p9_client_clunk(fid);
p9_fid_put(fid);
fid = NULL;
error:
......@@ -1459,15 +1459,6 @@ int p9_client_clunk(struct p9_fid *fid)
struct p9_req_t *req;
int retries = 0;
if (!fid || IS_ERR(fid)) {
pr_warn("%s (%d): Trying to clunk with invalid fid\n",
__func__, task_pid_nr(current));
dump_stack();
return 0;
}
if (!refcount_dec_and_test(&fid->count))
return 0;
again:
p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
fid->fid, retries);
......@@ -1519,7 +1510,7 @@ int p9_client_remove(struct p9_fid *fid)
p9_tag_remove(clnt, req);
error:
if (err == -ERESTARTSYS)
p9_client_clunk(fid);
p9_fid_put(fid);
else
p9_fid_destroy(fid);
return err;
......@@ -2042,7 +2033,7 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
attr_fid->fid, *attr_size);
return attr_fid;
clunk_fid:
p9_client_clunk(attr_fid);
p9_fid_put(attr_fid);
attr_fid = NULL;
error:
if (attr_fid && attr_fid != file_fid)
......
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