nfsd: Use vfs_fsync_range() in nfsd_commit
From: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
The NFS COMMIT operation allows the client to specify the exact byte range
that it wishes to sync to disk in order to optimise server performance.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/nfsd/vfs.c | 30 ++++++++++++++++++++----------
1 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 79d216f..ed024d3 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1141,8 +1141,9 @@ out:
#ifdef CONFIG_NFSD_V3
/*
* Commit all pending writes to stable storage.
- * Strictly speaking, we could sync just the indicated file region here,
- * but there's currently no way we can ask the VFS to do so.
+ *
+ * Note: we only guarantee that data that lies within the range specified
+ * by the 'offset' and 'count' parameters will be synced.
*
* Unfortunately we cannot lock the file to make sure we return full WCC
* data to the client, as locking happens lower down in the filesystem.
@@ -1152,23 +1153,32 @@ nfsd_commit(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long count)
{
struct file *file;
- __be32 err;
+ loff_t end = LLONG_MAX;
+ __be32 err = nfserr_inval;
- if ((u64)count > ~(u64)offset)
- return nfserr_inval;
+ if (offset < 0)
+ goto out;
+ if (count != 0) {
+ end = offset + (loff_t)count - 1;
+ if (end < offset)
+ goto out;
+ }
err = nfsd_open(rqstp, fhp, S_IFREG, NFSD_MAY_WRITE, &file);
if (err)
- return err;
+ goto out;
if (EX_ISSYNC(fhp->fh_export)) {
- if (file->f_op && file->f_op->fsync) {
- err = nfserrno(vfs_fsync(file, file->f_path.dentry, 0));
- } else {
+ int err2 = vfs_fsync_range(file, file->f_path.dentry,
+ offset, end, 0);
+
+ if (err2 != -EINVAL)
+ err = nfserrno(err2);
+ else
err = nfserr_notsupp;
- }
}
nfsd_close(file);
+out:
return err;
}
#endif /* CONFIG_NFSD_V3 */
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