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Diffstat (limited to 'fs/coda/file.c')
-rw-r--r--fs/coda/file.c70
1 files changed, 68 insertions, 2 deletions
diff --git a/fs/coda/file.c b/fs/coda/file.c
index 1cbc1f2298ee..43d371551d2b 100644
--- a/fs/coda/file.c
+++ b/fs/coda/file.c
@@ -27,6 +27,13 @@
#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)
{
@@ -61,6 +68,34 @@ coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
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)
{
@@ -68,6 +103,8 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
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);
@@ -76,6 +113,13 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
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);
@@ -89,6 +133,7 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
* 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;
}
@@ -97,7 +142,29 @@ coda_file_mmap(struct file *coda_file, struct vm_area_struct *vma)
cfi->cfi_mapcount++;
spin_unlock(&cii->c_lock);
- return call_mmap(host_file, vma);
+ 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)
@@ -207,4 +274,3 @@ const struct file_operations coda_file_operations = {
.fsync = coda_fsync,
.splice_read = generic_file_splice_read,
};
-