[RFC] v2 - [PATCH] filesystem helpers for custom 'struct file's
From: Dave Hansen
Date: Tue Oct 10 2006 - 14:26:37 EST
Some filesystems forego the vfs and may_open() and create their
own 'struct file's.
This patch creates a couple of helper functions which can be
used by these filesystems, and will provide a unified place
which the r/o bind mount code may patch.
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
---
lxc-dave/include/linux/file.h | 8 ++++
lxc-dave/fs/file_table.c | 30 +++++++++++++++
lxc-dave/fs/hugetlbfs/inode.c | 22 ++++-------
lxc-dave/mm/shmem.c | 22 ++++-------
lxc-dave/mm/tiny-shmem.c | 24 ++++--------
lxc-dave/net/socket.c | 82 +++++++++++++++++-------------------------
6 files changed, 99 insertions(+), 89 deletions(-)
diff -puN include/linux/file.h~B0-helpers-for-custom-struct_files include/linux/file.h
--- lxc/include/linux/file.h~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/include/linux/file.h 2006-10-10 10:55:14.000000000 -0700
@@ -67,6 +67,14 @@ struct files_struct {
extern void FASTCALL(__fput(struct file *));
extern void FASTCALL(fput(struct file *));
+struct file_operations;
+struct vfsmount;
+struct dentry;
+extern int init_file(struct file *, struct vfsmount *, struct dentry *dentry,
+ mode_t mode, const struct file_operations *fop);
+extern struct file *alloc_file(struct vfsmount *, struct dentry *dentry,
+ mode_t mode, const struct file_operations *fop);
+
static inline void fput_light(struct file *file, int fput_needed)
{
if (unlikely(fput_needed))
diff -puN fs/file_table.c~B0-helpers-for-custom-struct_files fs/file_table.c
--- lxc/fs/file_table.c~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/fs/file_table.c 2006-10-10 10:55:14.000000000 -0700
@@ -140,6 +140,36 @@ fail:
EXPORT_SYMBOL(get_empty_filp);
+struct file *alloc_file(struct vfsmount *mnt, struct dentry *dentry,
+ mode_t mode, const struct file_operations *fop)
+{
+ struct file *file;
+
+ file = get_empty_filp();
+ if (!file)
+ return NULL;
+
+ init_file(file, mnt, dentry, mode, fop);
+ return file;
+}
+
+EXPORT_SYMBOL(alloc_file);
+
+int init_file(struct file *file, struct vfsmount *mnt,
+ struct dentry *dentry, mode_t mode,
+ const struct file_operations *fop)
+{
+ int error = 0;
+ file->f_vfsmnt = mntget(mnt);
+ file->f_dentry = dentry;
+ file->f_mapping = dentry->d_inode->i_mapping;
+ file->f_mode = mode;
+ file->f_op = fop;
+ return error;
+}
+
+EXPORT_SYMBOL(init_file);
+
void fastcall fput(struct file *file)
{
if (atomic_dec_and_test(&file->f_count))
diff -puN fs/hugetlbfs/inode.c~B0-helpers-for-custom-struct_files fs/hugetlbfs/inode.c
--- lxc/fs/hugetlbfs/inode.c~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/fs/hugetlbfs/inode.c 2006-10-10 10:55:14.000000000 -0700
@@ -764,16 +764,11 @@ struct file *hugetlb_zero_setup(size_t s
if (!dentry)
goto out_shm_unlock;
- error = -ENFILE;
- file = get_empty_filp();
- if (!file)
- goto out_dentry;
-
error = -ENOSPC;
inode = hugetlbfs_get_inode(root->d_sb, current->fsuid,
current->fsgid, S_IFREG | S_IRWXUGO, 0);
if (!inode)
- goto out_file;
+ goto out_dentry;
error = -ENOMEM;
if (hugetlb_reserve_pages(inode, 0, size >> HPAGE_SHIFT))
@@ -782,17 +777,18 @@ struct file *hugetlb_zero_setup(size_t s
d_instantiate(dentry, inode);
inode->i_size = size;
inode->i_nlink = 0;
- file->f_vfsmnt = mntget(hugetlbfs_vfsmount);
- file->f_dentry = dentry;
- file->f_mapping = inode->i_mapping;
- file->f_op = &hugetlbfs_file_operations;
- file->f_mode = FMODE_WRITE | FMODE_READ;
+
+ error = -ENFILE;
+ file = alloc_file(hugetlbfs_vfsmount, dentry,
+ FMODE_WRITE | FMODE_READ,
+ &hugetlbfs_file_operations);
+ if (!file)
+ goto out_inode;
+
return file;
out_inode:
iput(inode);
-out_file:
- put_filp(file);
out_dentry:
dput(dentry);
out_shm_unlock:
diff -puN mm/shmem.c~B0-helpers-for-custom-struct_files mm/shmem.c
--- lxc/mm/shmem.c~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/mm/shmem.c 2006-10-10 10:55:14.000000000 -0700
@@ -2464,29 +2464,25 @@ struct file *shmem_file_setup(char *name
if (!dentry)
goto put_memory;
- error = -ENFILE;
- file = get_empty_filp();
- if (!file)
- goto put_dentry;
-
error = -ENOSPC;
inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
if (!inode)
- goto close_file;
+ goto put_dentry;
+
+ error = -ENFILE;
+ file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+ &shmem_file_operations);
+ if (!file)
+ goto put_inode;
SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
d_instantiate(dentry, inode);
inode->i_size = size;
inode->i_nlink = 0; /* It is unlinked */
- file->f_vfsmnt = mntget(shm_mnt);
- file->f_dentry = dentry;
- file->f_mapping = inode->i_mapping;
- file->f_op = &shmem_file_operations;
- file->f_mode = FMODE_WRITE | FMODE_READ;
return file;
-close_file:
- put_filp(file);
+put_inode:
+ iput(inode);
put_dentry:
dput(dentry);
put_memory:
diff -puN mm/tiny-shmem.c~B0-helpers-for-custom-struct_files mm/tiny-shmem.c
--- lxc/mm/tiny-shmem.c~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/mm/tiny-shmem.c 2006-10-10 10:55:14.000000000 -0700
@@ -66,24 +66,19 @@ struct file *shmem_file_setup(char *name
if (!dentry)
goto put_memory;
- error = -ENFILE;
- file = get_empty_filp();
- if (!file)
- goto put_dentry;
-
error = -ENOSPC;
inode = ramfs_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
if (!inode)
- goto close_file;
+ goto put_dentry;
d_instantiate(dentry, inode);
- inode->i_nlink = 0; /* It is unlinked */
+ error = -ENFILE;
+ file = alloc_file(shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+ &ramfs_file_operations);
+ if (!file)
+ goto put_inode;
- file->f_vfsmnt = mntget(shm_mnt);
- file->f_dentry = dentry;
- file->f_mapping = inode->i_mapping;
- file->f_op = &ramfs_file_operations;
- file->f_mode = FMODE_WRITE | FMODE_READ;
+ inode->i_nlink = 0; /* It is unlinked */
/* notify everyone as to the change of file size */
error = do_truncate(dentry, size, 0, file);
@@ -91,9 +86,8 @@ struct file *shmem_file_setup(char *name
goto close_file;
return file;
-
-close_file:
- put_filp(file);
+put_inode:
+ iput(inode);
put_dentry:
dput(dentry);
put_memory:
diff -puN net/socket.c~B0-helpers-for-custom-struct_files net/socket.c
--- lxc/net/socket.c~B0-helpers-for-custom-struct_files 2006-10-10 10:54:31.000000000 -0700
+++ lxc-dave/net/socket.c 2006-10-10 10:55:14.000000000 -0700
@@ -330,26 +330,10 @@ static struct dentry_operations sockfs_d
* but we take care of internal coherence yet.
*/
-static int sock_alloc_fd(struct file **filep)
-{
- int fd;
-
- fd = get_unused_fd();
- if (likely(fd >= 0)) {
- struct file *file = get_empty_filp();
-
- *filep = file;
- if (unlikely(!file)) {
- put_unused_fd(fd);
- return -ENFILE;
- }
- } else
- *filep = NULL;
- return fd;
-}
-
-static int sock_attach_fd(struct socket *sock, struct file *file)
+struct file *sock_alloc_file(struct socket *sock)
{
+ struct file *file;
+ struct dentry *dentry;
struct qstr this;
char name[32];
@@ -357,40 +341,39 @@ static int sock_attach_fd(struct socket
this.name = name;
this.hash = SOCK_INODE(sock)->i_ino;
- file->f_dentry = d_alloc(sock_mnt->mnt_sb->s_root, &this);
- if (unlikely(!file->f_dentry))
- return -ENOMEM;
-
- file->f_dentry->d_op = &sockfs_dentry_operations;
- d_add(file->f_dentry, SOCK_INODE(sock));
- file->f_vfsmnt = mntget(sock_mnt);
- file->f_mapping = file->f_dentry->d_inode->i_mapping;
-
+ dentry = d_alloc(sock_mnt->mnt_sb->s_root, &this);
+ if (unlikely(!dentry))
+ return ERR_PTR(-ENOMEM);
+
+ dentry->d_op = &sockfs_dentry_operations;
+ d_add(dentry, SOCK_INODE(sock));
+ file = alloc_file(sock_mnt, dentry, FMODE_READ | FMODE_WRITE,
+ &socket_file_ops);
+ if (!file) {
+ dput(dentry);
+ return ERR_PTR(-ENOMEM);
+ }
+ SOCK_INODE(sock)->i_fop = &socket_file_ops;
sock->file = file;
- file->f_op = SOCK_INODE(sock)->i_fop = &socket_file_ops;
- file->f_mode = FMODE_READ | FMODE_WRITE;
file->f_flags = O_RDWR;
file->f_pos = 0;
file->private_data = sock;
- return 0;
+ return file;
}
int sock_map_fd(struct socket *sock)
{
struct file *newfile;
- int fd = sock_alloc_fd(&newfile);
+ int fd = get_unused_fd();
- if (likely(fd >= 0)) {
- int err = sock_attach_fd(sock, newfile);
+ newfile = sock_alloc_file(sock);
- if (unlikely(err < 0)) {
- put_filp(newfile);
- put_unused_fd(fd);
- return err;
- }
- fd_install(fd, newfile);
+ if (IS_ERR(newfile)) {
+ put_unused_fd(fd);
+ return PTR_ERR(newfile);
}
+ fd_install(fd, newfile);
return fd;
}
@@ -1355,35 +1338,37 @@ asmlinkage long sys_accept(int fd, struc
*/
__module_get(newsock->ops->owner);
- newfd = sock_alloc_fd(&newfile);
+ newfd = get_unused_fd();
if (unlikely(newfd < 0)) {
err = newfd;
sock_release(newsock);
goto out_put;
}
- err = sock_attach_fd(newsock, newfile);
- if (err < 0)
+ newfile = sock_alloc_file(newsock);
+ if (IS_ERR(newfile)) {
+ err = PTR_ERR(newfile);
goto out_fd;
+ }
err = security_socket_accept(sock, newsock);
if (err)
- goto out_fd;
+ goto out_file;
err = sock->ops->accept(sock, newsock, sock->file->f_flags);
if (err < 0)
- goto out_fd;
+ goto out_file;
if (upeer_sockaddr) {
if (newsock->ops->getname(newsock, (struct sockaddr *)address,
&len, 2) < 0) {
err = -ECONNABORTED;
- goto out_fd;
+ goto out_file;
}
err = move_addr_to_user(address, len, upeer_sockaddr,
upeer_addrlen);
if (err < 0)
- goto out_fd;
+ goto out_file;
}
/* File flags are not inherited via accept() unlike another OSes. */
@@ -1397,8 +1382,9 @@ out_put:
fput_light(sock->file, fput_needed);
out:
return err;
-out_fd:
+out_file:
fput(newfile);
+out_fd:
put_unused_fd(newfd);
goto out_put;
}
_
-
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