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/ecryptfs/file.c b/fs/ecryptfs/file.c
index eb3dc4c..7138343 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -275,18 +275,9 @@
static int
ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
{
- struct file *lower_file = ecryptfs_file_to_lower(file);
- struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
- struct inode *lower_inode = lower_dentry->d_inode;
- int rc = -EINVAL;
-
- if (lower_inode->i_fop->fsync) {
- mutex_lock(&lower_inode->i_mutex);
- rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
- datasync);
- mutex_unlock(&lower_inode->i_mutex);
- }
- return rc;
+ return vfs_fsync(ecryptfs_file_to_lower(file),
+ ecryptfs_dentry_to_lower(dentry),
+ datasync);
}
static int ecryptfs_fasync(int fd, struct file *file, int flag)