add a vfs_fsync helper
Fsync currently has a fdatawrite/fdatawait pair around the method call,
and a mutex_lock/unlock of the inode mutex. All callers of fsync have
to duplicate this, but we have a few and most of them don't quite get
it right. This patch adds a new vfs_fsync that takes care of this.
It's a little more complicated as usual as ->fsync might get a NULL file
pointer and just a dentry from nfsd, but otherwise gets afile and we
want to take the mapping and file operations from it when it is there.
Notes on the fsync callers:
- ecryptfs wasn't calling filemap_fdatawrite / filemap_fdatawait on the
lower file
- coda wasn't calling filemap_fdatawrite / filemap_fdatawait on the host
file, and returning 0 when ->fsync was missing
- shm wasn't calling either filemap_fdatawrite / filemap_fdatawait nor
taking i_mutex. Now given that shared memory doesn't have disk
backing not doing anything in fsync seems fine and I left it out of
the vfs_fsync conversion for now, but in that case we might just
not pass it through to the lower file at all but just call the no-op
simple_sync_file directly.
[and now actually export vfs_fsync]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/coda/file.c b/fs/coda/file.c
index 466303d..6a347fb 100644
--- a/fs/coda/file.c
+++ b/fs/coda/file.c
@@ -201,8 +201,7 @@
int coda_fsync(struct file *coda_file, struct dentry *coda_dentry, int datasync)
{
struct file *host_file;
- struct dentry *host_dentry;
- struct inode *host_inode, *coda_inode = coda_dentry->d_inode;
+ struct inode *coda_inode = coda_dentry->d_inode;
struct coda_file_info *cfi;
int err = 0;
@@ -214,14 +213,7 @@
BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
host_file = cfi->cfi_container;
- if (host_file->f_op && host_file->f_op->fsync) {
- host_dentry = host_file->f_path.dentry;
- host_inode = host_dentry->d_inode;
- mutex_lock(&host_inode->i_mutex);
- err = host_file->f_op->fsync(host_file, host_dentry, datasync);
- mutex_unlock(&host_inode->i_mutex);
- }
-
+ err = vfs_fsync(host_file, host_file->f_path.dentry, datasync);
if ( !err && !datasync ) {
lock_kernel();
err = venus_fsync(coda_inode->i_sb, coda_i2f(coda_inode));