From: NeilBrown <neil@xxxxxxxxxx>
These are partners of simple_start_creating().
On failure we don't keep a reference. On success we do.
We now Use these where simple_start_creating() is used, in debugfs,
tracefs, and rpcpipefs.
This is part of centralising all locking for create/remote/rename
operations.
Also rename start_creating, end_creating, failed_creating in debugfs to
free up these generic names for more generic use.
Signed-off-by: NeilBrown <neil@xxxxxxxxxx>
---
fs/debugfs/inode.c | 43 +++++++++++++++++++++----------------------
fs/tracefs/inode.c | 6 ++----
include/linux/fs.h | 19 +++++++++++++++++++
net/sunrpc/rpc_pipe.c | 11 ++++-------
4 files changed, 46 insertions(+), 33 deletions(-)
diff --git a/fs/debugfs/inode.c b/fs/debugfs/inode.c
index c12d649df6a5..1a13739b2cef 100644
--- a/fs/debugfs/inode.c
+++ b/fs/debugfs/inode.c
@@ -362,7 +362,8 @@ struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
}
EXPORT_SYMBOL_GPL(debugfs_lookup);
-static struct dentry *start_creating(const char *name, struct dentry *parent)
+static struct dentry *debugfs_start_creating(const char *name,
+ struct dentry *parent)
{
struct dentry *dentry;
int error;
@@ -402,18 +403,16 @@ static struct dentry *start_creating(const char *name, struct dentry *parent)
return dentry;
}
-static struct dentry *failed_creating(struct dentry *dentry)
+static struct dentry *debugfs_failed_creating(struct dentry *dentry)
{
- inode_unlock(d_inode(dentry->d_parent));
- dput(dentry);
+ simple_failed_creating(dentry);
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
return ERR_PTR(-ENOMEM);
}
-static struct dentry *end_creating(struct dentry *dentry)
+static struct dentry *debugfs_end_creating(struct dentry *dentry)
{
- inode_unlock(d_inode(dentry->d_parent));
- return dentry;
+ return simple_end_creating(dentry);
}
static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
@@ -428,13 +427,13 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
if (!(mode & S_IFMT))
mode |= S_IFREG;
BUG_ON(!S_ISREG(mode));
- dentry = start_creating(name, parent);
+ dentry = debugfs_start_creating(name, parent);
if (IS_ERR(dentry))
return dentry;
if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
- failed_creating(dentry);
+ debugfs_failed_creating(dentry);
return ERR_PTR(-EPERM);
}
@@ -442,7 +441,7 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create file '%s'\n",
name);
- return failed_creating(dentry);
+ return debugfs_failed_creating(dentry);
}
inode->i_mode = mode;
@@ -457,7 +456,7 @@ static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
d_instantiate(dentry, inode);
fsnotify_create(d_inode(dentry->d_parent), dentry);
- return end_creating(dentry);
+ return debugfs_end_creating(dentry);
}
struct dentry *debugfs_create_file_full(const char *name, umode_t mode,
@@ -577,14 +576,14 @@ EXPORT_SYMBOL_GPL(debugfs_create_file_size);
*/
struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
{
- struct dentry *dentry = start_creating(name, parent);
+ struct dentry *dentry = debugfs_start_creating(name, parent);
struct inode *inode;
if (IS_ERR(dentry))
return dentry;
if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
- failed_creating(dentry);
+ debugfs_failed_creating(dentry);
return ERR_PTR(-EPERM);
}
@@ -592,7 +591,7 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create directory '%s'\n",
name);
- return failed_creating(dentry);
+ return debugfs_failed_creating(dentry);
}
inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
@@ -604,7 +603,7 @@ struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
d_instantiate(dentry, inode);
inc_nlink(d_inode(dentry->d_parent));
fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
- return end_creating(dentry);
+ return debugfs_end_creating(dentry);
}
EXPORT_SYMBOL_GPL(debugfs_create_dir);
@@ -624,14 +623,14 @@ struct dentry *debugfs_create_automount(const char *name,
debugfs_automount_t f,
void *data)
{
- struct dentry *dentry = start_creating(name, parent);
+ struct dentry *dentry = debugfs_start_creating(name, parent);
struct inode *inode;
if (IS_ERR(dentry))
return dentry;
if (!(debugfs_allow & DEBUGFS_ALLOW_API)) {
- failed_creating(dentry);
+ debugfs_failed_creating(dentry);
return ERR_PTR(-EPERM);
}
@@ -639,7 +638,7 @@ struct dentry *debugfs_create_automount(const char *name,
if (unlikely(!inode)) {
pr_err("out of free dentries, can not create automount '%s'\n",
name);
- return failed_creating(dentry);
+ return debugfs_failed_creating(dentry);
}
make_empty_dir_inode(inode);
@@ -651,7 +650,7 @@ struct dentry *debugfs_create_automount(const char *name,
d_instantiate(dentry, inode);
inc_nlink(d_inode(dentry->d_parent));
fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
- return end_creating(dentry);
+ return debugfs_end_creating(dentry);
}
EXPORT_SYMBOL(debugfs_create_automount);
@@ -687,7 +686,7 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
if (!link)
return ERR_PTR(-ENOMEM);
- dentry = start_creating(name, parent);
+ dentry = debugfs_start_creating(name, parent);
if (IS_ERR(dentry)) {
kfree(link);
return dentry;
@@ -698,13 +697,13 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
pr_err("out of free dentries, can not create symlink '%s'\n",
name);
kfree(link);
- return failed_creating(dentry);
+ return debugfs_failed_creating(dentry);
}
inode->i_mode = S_IFLNK | S_IRWXUGO;
inode->i_op = &debugfs_symlink_inode_operations;
inode->i_link = link;
d_instantiate(dentry, inode);
- return end_creating(dentry);
+ return debugfs_end_creating(dentry);
}
EXPORT_SYMBOL_GPL(debugfs_create_symlink);
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index 0c023941a316..320d7f25024b 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -571,16 +571,14 @@ struct dentry *tracefs_start_creating(const char *name, struct dentry *parent)
struct dentry *tracefs_failed_creating(struct dentry *dentry)
{
- inode_unlock(d_inode(dentry->d_parent));
- dput(dentry);
+ simple_failed_creating(dentry);
simple_release_fs(&tracefs_mount, &tracefs_mount_count);
return NULL;
}
struct dentry *tracefs_end_creating(struct dentry *dentry)
{
- inode_unlock(d_inode(dentry->d_parent));
- return dentry;
+ return simple_end_creating(dentry);
}
/* Find the inode that this will use for default */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 73b39e5bb9e4..f2b5456305e2 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3656,6 +3656,25 @@ extern int simple_pin_fs(struct file_system_type *, struct vfsmount **mount, int
extern void simple_release_fs(struct vfsmount **mount, int *count);
struct dentry *simple_start_creating(struct dentry *, const char *);
+/* filesystems which use the dcache as backing store don't
+ * drop the reference after creating an object - they keep it
+ * to be dropped by kill_litter_super().
+ */
+static inline struct dentry *simple_end_creating(struct dentry *dentry)
+{
+ inode_unlock(dentry->d_parent->d_inode);
+ return dentry;
+}
+
+/* On failure, we DO drop the reference because there is no need
+ * keep it.
+ */
+static inline void simple_failed_creating(struct dentry *dentry)
+{
+ inode_unlock(dentry->d_parent->d_inode);
+ dput(dentry);
+}
+
extern ssize_t simple_read_from_buffer(void __user *to, size_t count,
loff_t *ppos, const void *from, size_t available);
extern ssize_t simple_write_to_buffer(void *to, size_t available, loff_t *ppos,
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 0bd1df2ebb47..38c26909235d 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -536,8 +536,7 @@ static int rpc_new_file(struct dentry *parent,
inode = rpc_get_inode(dir->i_sb, S_IFREG | mode);
if (unlikely(!inode)) {
- dput(dentry);
- inode_unlock(dir);
+ simple_failed_creating(dentry);
return -ENOMEM;
}
inode->i_ino = iunique(dir->i_sb, 100);
@@ -546,7 +545,7 @@ static int rpc_new_file(struct dentry *parent,
rpc_inode_setowner(inode, private);
d_instantiate(dentry, inode);
fsnotify_create(dir, dentry);
- inode_unlock(dir);
+ simple_end_creating(dentry);
return 0;
}
@@ -572,9 +571,8 @@ static struct dentry *rpc_new_dir(struct dentry *parent,
inc_nlink(dir);
d_instantiate(dentry, inode);
fsnotify_mkdir(dir, dentry);
- inode_unlock(dir);
- return dentry;
+ return simple_end_creating(dentry);
}
static int rpc_populate(struct dentry *parent,
@@ -669,9 +667,8 @@ int rpc_mkpipe_dentry(struct dentry *parent, const char *name,
rpci->pipe = pipe;
rpc_inode_setowner(inode, private);
d_instantiate(dentry, inode);
- pipe->dentry = dentry;
fsnotify_create(dir, dentry);
- inode_unlock(dir);
+ pipe->dentry = simple_end_creating(dentry);
return 0;
failed:
--
2.50.0.107.gf914562f5916.dirty
