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/nfsd/vfs.c b/fs/nfsd/vfs.c
index 5245a39..44aa92a 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -744,45 +744,16 @@
fput(filp);
}
-/*
- * Sync a file
- * As this calls fsync (not fdatasync) there is no need for a write_inode
- * after it.
- */
-static inline int nfsd_dosync(struct file *filp, struct dentry *dp,
- const struct file_operations *fop)
-{
- struct inode *inode = dp->d_inode;
- int (*fsync) (struct file *, struct dentry *, int);
- int err;
-
- err = filemap_fdatawrite(inode->i_mapping);
- if (err == 0 && fop && (fsync = fop->fsync))
- err = fsync(filp, dp, 0);
- if (err == 0)
- err = filemap_fdatawait(inode->i_mapping);
-
- return err;
-}
-
-
static int
nfsd_sync(struct file *filp)
{
- int err;
- struct inode *inode = filp->f_path.dentry->d_inode;
- dprintk("nfsd: sync file %s\n", filp->f_path.dentry->d_name.name);
- mutex_lock(&inode->i_mutex);
- err=nfsd_dosync(filp, filp->f_path.dentry, filp->f_op);
- mutex_unlock(&inode->i_mutex);
-
- return err;
+ return vfs_fsync(filp, filp->f_path.dentry, 0);
}
int
-nfsd_sync_dir(struct dentry *dp)
+nfsd_sync_dir(struct dentry *dentry)
{
- return nfsd_dosync(NULL, dp, dp->d_inode->i_fop);
+ return vfs_fsync(NULL, dentry, 0);
}
/*