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kernfs: don't set dentry->d_fsdata

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When working on adding exportfs operations in kernfs, I found it's hard
to initialize dentry->d_fsdata in the exportfs operations. Looks there
is no way to do it without race condition. Look at the kernfs code
closely, there is no point to set dentry->d_fsdata. inode->i_private
already points to kernfs_node, and we can get inode from a dentry. So
this patch just delete the d_fsdata usage.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Shaohua Li
2017-07-12 11:49:49 -07:00
committed by Jens Axboe
parent ba16b2846a
commit 319ba91d35
6 changed files with 27 additions and 31 deletions
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25
fs/kernfs/dir.c
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@@ -566,7 +566,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
if (d_really_is_negative(dentry))
goto out_bad_unlocked;
kn = dentry->d_fsdata;
kn = kernfs_dentry_node(dentry);
mutex_lock(&kernfs_mutex);
/* The kernfs node has been deactivated */
@@ -574,7 +574,7 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
goto out_bad;
/* The kernfs node has been moved? */
if (dentry->d_parent->d_fsdata != kn->parent)
if (kernfs_dentry_node(dentry->d_parent) != kn->parent)
goto out_bad;
/* The kernfs node has been renamed */
@@ -594,14 +594,8 @@ out_bad_unlocked:
return 0;
}
static void kernfs_dop_release(struct dentry *dentry)
{
kernfs_put(dentry->d_fsdata);
}
const struct dentry_operations kernfs_dops = {
.d_revalidate = kernfs_dop_revalidate,
.d_release = kernfs_dop_release,
};
/**
@@ -617,8 +611,9 @@ const struct dentry_operations kernfs_dops = {
*/
struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
{
if (dentry->d_sb->s_op == &kernfs_sops)
return dentry->d_fsdata;
if (dentry->d_sb->s_op == &kernfs_sops &&
!d_really_is_negative(dentry))
return kernfs_dentry_node(dentry);
return NULL;
}
@@ -1056,7 +1051,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
unsigned int flags)
{
struct dentry *ret;
struct kernfs_node *parent = dentry->d_parent->d_fsdata;
struct kernfs_node *parent = dir->i_private;
struct kernfs_node *kn;
struct inode *inode;
const void *ns = NULL;
@@ -1073,8 +1068,6 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
ret = NULL;
goto out_unlock;
}
kernfs_get(kn);
dentry->d_fsdata = kn;
/* attach dentry and inode */
inode = kernfs_get_inode(dir->i_sb, kn);
@@ -1111,7 +1104,7 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
{
struct kernfs_node *kn = dentry->d_fsdata;
struct kernfs_node *kn = kernfs_dentry_node(dentry);
struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
int ret;
@@ -1131,7 +1124,7 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
struct kernfs_node *kn = old_dentry->d_fsdata;
struct kernfs_node *kn = kernfs_dentry_node(old_dentry);
struct kernfs_node *new_parent = new_dir->i_private;
struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
int ret;
@@ -1644,7 +1637,7 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
static int kernfs_fop_readdir(struct file *file, struct dir_context *ctx)
{
struct dentry *dentry = file->f_path.dentry;
struct kernfs_node *parent = dentry->d_fsdata;
struct kernfs_node *parent = kernfs_dentry_node(dentry);
struct kernfs_node *pos = file->private_data;
const void *ns = NULL;