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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /fs/coda/file.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/coda/file.c')
-rw-r--r-- | fs/coda/file.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/fs/coda/file.c b/fs/coda/file.c new file mode 100644 index 000000000..43d371551 --- /dev/null +++ b/fs/coda/file.c @@ -0,0 +1,276 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * File operations for Coda. + * Original version: (C) 1996 Peter Braam + * Rewritten for Linux 2.1: (C) 1997 Carnegie Mellon University + * + * Carnegie Mellon encourages users of this code to contribute improvements + * to the Coda project. Contact Peter Braam <coda@cs.cmu.edu>. + */ + +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/time.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/stat.h> +#include <linux/cred.h> +#include <linux/errno.h> +#include <linux/spinlock.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/uaccess.h> + +#include <linux/coda.h> +#include <linux/coda_psdev.h> + +#include "coda_linux.h" +#include "coda_int.h" + +struct coda_vm_ops { + atomic_t refcnt; + struct file *coda_file; + const struct vm_operations_struct *host_vm_ops; + struct vm_operations_struct vm_ops; +}; + +static ssize_t +coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *coda_file = iocb->ki_filp; + struct coda_file_info *cfi = CODA_FTOC(coda_file); + + BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); + + return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos, 0); +} + +static ssize_t +coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to) +{ + struct file *coda_file = iocb->ki_filp; + struct inode *coda_inode = file_inode(coda_file); + struct coda_file_info *cfi = CODA_FTOC(coda_file); + struct file *host_file; + ssize_t ret; + + BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); + + host_file = cfi->cfi_container; + file_start_write(host_file); + inode_lock(coda_inode); + ret = vfs_iter_write(cfi->cfi_container, to, &iocb->ki_pos, 0); + coda_inode->i_size = file_inode(host_file)->i_size; + coda_inode->i_blocks = (coda_inode->i_size + 511) >> 9; + coda_inode->i_mtime = coda_inode->i_ctime = current_time(coda_inode); + inode_unlock(coda_inode); + file_end_write(host_file); + return ret; +} + +static void +coda_vm_open(struct vm_area_struct *vma) +{ + struct coda_vm_ops *cvm_ops = + container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); + + atomic_inc(&cvm_ops->refcnt); + + if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->open) + cvm_ops->host_vm_ops->open(vma); +} + +static void +coda_vm_close(struct vm_area_struct *vma) +{ + struct coda_vm_ops *cvm_ops = + container_of(vma->vm_ops, struct coda_vm_ops, vm_ops); + + if (cvm_ops->host_vm_ops && cvm_ops->host_vm_ops->close) + cvm_ops->host_vm_ops->close(vma); + + if (atomic_dec_and_test(&cvm_ops->refcnt)) { + vma->vm_ops = cvm_ops->host_vm_ops; + fput(cvm_ops->coda_file); + kfree(cvm_ops); + } +} + +static int +coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma) +{ + struct coda_file_info *cfi; + struct coda_inode_info *cii; + struct file *host_file; + struct inode *coda_inode, *host_inode; + struct coda_vm_ops *cvm_ops; + int ret; + + cfi = CODA_FTOC(coda_file); + BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); + host_file = cfi->cfi_container; + + if (!host_file->f_op->mmap) + return -ENODEV; + + if (WARN_ON(coda_file != vma->vm_file)) + return -EIO; + + cvm_ops = kmalloc(sizeof(struct coda_vm_ops), GFP_KERNEL); + if (!cvm_ops) + return -ENOMEM; + + coda_inode = file_inode(coda_file); + host_inode = file_inode(host_file); + + cii = ITOC(coda_inode); + spin_lock(&cii->c_lock); + coda_file->f_mapping = host_file->f_mapping; + if (coda_inode->i_mapping == &coda_inode->i_data) + coda_inode->i_mapping = host_inode->i_mapping; + + /* only allow additional mmaps as long as userspace isn't changing + * the container file on us! */ + else if (coda_inode->i_mapping != host_inode->i_mapping) { + spin_unlock(&cii->c_lock); + kfree(cvm_ops); + return -EBUSY; + } + + /* keep track of how often the coda_inode/host_file has been mmapped */ + cii->c_mapcount++; + cfi->cfi_mapcount++; + spin_unlock(&cii->c_lock); + + vma->vm_file = get_file(host_file); + ret = call_mmap(vma->vm_file, vma); + + if (ret) { + /* if call_mmap fails, our caller will put coda_file so we + * should drop the reference to the host_file that we got. + */ + fput(host_file); + kfree(cvm_ops); + } else { + /* here we add redirects for the open/close vm_operations */ + cvm_ops->host_vm_ops = vma->vm_ops; + if (vma->vm_ops) + cvm_ops->vm_ops = *vma->vm_ops; + + cvm_ops->vm_ops.open = coda_vm_open; + cvm_ops->vm_ops.close = coda_vm_close; + cvm_ops->coda_file = coda_file; + atomic_set(&cvm_ops->refcnt, 1); + + vma->vm_ops = &cvm_ops->vm_ops; + } + return ret; +} + +int coda_open(struct inode *coda_inode, struct file *coda_file) +{ + struct file *host_file = NULL; + int error; + unsigned short flags = coda_file->f_flags & (~O_EXCL); + unsigned short coda_flags = coda_flags_to_cflags(flags); + struct coda_file_info *cfi; + + cfi = kmalloc(sizeof(struct coda_file_info), GFP_KERNEL); + if (!cfi) + return -ENOMEM; + + error = venus_open(coda_inode->i_sb, coda_i2f(coda_inode), coda_flags, + &host_file); + if (!host_file) + error = -EIO; + + if (error) { + kfree(cfi); + return error; + } + + host_file->f_flags |= coda_file->f_flags & (O_APPEND | O_SYNC); + + cfi->cfi_magic = CODA_MAGIC; + cfi->cfi_mapcount = 0; + cfi->cfi_container = host_file; + + BUG_ON(coda_file->private_data != NULL); + coda_file->private_data = cfi; + return 0; +} + +int coda_release(struct inode *coda_inode, struct file *coda_file) +{ + unsigned short flags = (coda_file->f_flags) & (~O_EXCL); + unsigned short coda_flags = coda_flags_to_cflags(flags); + struct coda_file_info *cfi; + struct coda_inode_info *cii; + struct inode *host_inode; + int err; + + cfi = CODA_FTOC(coda_file); + BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); + + err = venus_close(coda_inode->i_sb, coda_i2f(coda_inode), + coda_flags, coda_file->f_cred->fsuid); + + host_inode = file_inode(cfi->cfi_container); + cii = ITOC(coda_inode); + + /* did we mmap this file? */ + spin_lock(&cii->c_lock); + if (coda_inode->i_mapping == &host_inode->i_data) { + cii->c_mapcount -= cfi->cfi_mapcount; + if (!cii->c_mapcount) + coda_inode->i_mapping = &coda_inode->i_data; + } + spin_unlock(&cii->c_lock); + + fput(cfi->cfi_container); + kfree(coda_file->private_data); + coda_file->private_data = NULL; + + /* VFS fput ignores the return value from file_operations->release, so + * there is no use returning an error here */ + return 0; +} + +int coda_fsync(struct file *coda_file, loff_t start, loff_t end, int datasync) +{ + struct file *host_file; + struct inode *coda_inode = file_inode(coda_file); + struct coda_file_info *cfi; + int err; + + if (!(S_ISREG(coda_inode->i_mode) || S_ISDIR(coda_inode->i_mode) || + S_ISLNK(coda_inode->i_mode))) + return -EINVAL; + + err = filemap_write_and_wait_range(coda_inode->i_mapping, start, end); + if (err) + return err; + inode_lock(coda_inode); + + cfi = CODA_FTOC(coda_file); + BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC); + host_file = cfi->cfi_container; + + err = vfs_fsync(host_file, datasync); + if (!err && !datasync) + err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode)); + inode_unlock(coda_inode); + + return err; +} + +const struct file_operations coda_file_operations = { + .llseek = generic_file_llseek, + .read_iter = coda_file_read_iter, + .write_iter = coda_file_write_iter, + .mmap = coda_file_mmap, + .open = coda_open, + .release = coda_release, + .fsync = coda_fsync, + .splice_read = generic_file_splice_read, +}; |