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9p fid refcount: add p9_fid_get/put wrappers

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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.org
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
This commit is contained in:
Dominique Martinet 2022-06-12 13:42:32 +09:00 committed by Dominique Martinet
parent b296d05746
commit b48dbb998d
12 changed files with 100 additions and 81 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
fs/9p/fid.c
View File

@ -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;
}

2
fs/9p/fid.h
View File

@ -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

4
fs/9p/vfs_addr.c
View File

@ -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);
}
/**

4
fs/9p/vfs_dentry.c
View File

@ -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;

2
fs/9p/vfs_dir.c
View File

@ -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)) {

4
fs/9p/vfs_file.c
View File

@ -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;
}

48
fs/9p/vfs_inode.c
View File

@ -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;
}

42
fs/9p/vfs_inode_dotl.c
View File

@ -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);

6
fs/9p/vfs_super.c
View File

@ -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;
}

8
fs/9p/xattr.c
View File

@ -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;

28
include/net/9p/client.h
View File

@ -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,

15
net/9p/client.c
View File

@ -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)