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Diffstat (limited to 'fs')
-rw-r--r--fs/dcache.c31
-rw-r--r--fs/pipe.c18
2 files changed, 43 insertions, 6 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 268da2e2bc09..2135ab8bb103 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1853,6 +1853,16 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
struct vfsmount *rootmnt;
struct dentry *root;
+ /*
+ * We have various synthetic filesystems that never get mounted. On
+ * these filesystems dentries are never used for lookup purposes, and
+ * thus don't need to be hashed. They also don't need a name until a
+ * user wants to identify the object in /proc/pid/fd/. The little hack
+ * below allows us to generate a name for these objects on demand:
+ */
+ if (dentry->d_op && dentry->d_op->d_dname)
+ return dentry->d_op->d_dname(dentry, buf, buflen);
+
read_lock(&current->fs->lock);
rootmnt = mntget(current->fs->rootmnt);
root = dget(current->fs->root);
@@ -1866,6 +1876,27 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
}
/*
+ * Helper function for dentry_operations.d_dname() members
+ */
+char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
+ const char *fmt, ...)
+{
+ va_list args;
+ char temp[64];
+ int sz;
+
+ va_start(args, fmt);
+ sz = vsnprintf(temp, sizeof(temp), fmt, args) + 1;
+ va_end(args);
+
+ if (sz > sizeof(temp) || sz > buflen)
+ return ERR_PTR(-ENAMETOOLONG);
+
+ buffer += buflen - sz;
+ return memcpy(buffer, temp, sz);
+}
+
+/*
* NOTE! The user-level library version returns a
* character pointer. The kernel system call just
* returns the length of the buffer filled (which
diff --git a/fs/pipe.c b/fs/pipe.c
index ebafde7d6aba..3a89592bdf57 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -841,8 +841,18 @@ static int pipefs_delete_dentry(struct dentry *dentry)
return 0;
}
+/*
+ * pipefs_dname() is called from d_path().
+ */
+static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+ return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
+ dentry->d_inode->i_ino);
+}
+
static struct dentry_operations pipefs_dentry_operations = {
.d_delete = pipefs_delete_dentry,
+ .d_dname = pipefs_dname,
};
static struct inode * get_pipe_inode(void)
@@ -888,8 +898,7 @@ struct file *create_write_pipe(void)
struct inode *inode;
struct file *f;
struct dentry *dentry;
- char name[32];
- struct qstr this;
+ struct qstr name = { .name = "" };
f = get_empty_filp();
if (!f)
@@ -899,11 +908,8 @@ struct file *create_write_pipe(void)
if (!inode)
goto err_file;
- this.len = sprintf(name, "[%lu]", inode->i_ino);
- this.name = name;
- this.hash = 0;
err = -ENOMEM;
- dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
+ dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &name);
if (!dentry)
goto err_inode;