Currently nfs_updatepage allows a write to be extended to cover a full
page only if we don't have a byte range lock lock on the file... but if
we have a write delegation on the file or if we have the whole file
locked for writing then we should be allowed to extend the write as
well.
Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
---
fs/nfs/write.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index a2c7c28..c8a1bcc 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -888,6 +888,28 @@ out:
return PageUptodate(page) != 0;
}
+/* If we know the page is up to date, and we're not using byte range locks (or
+ * if we have the whole file locked for writing), it may be more efficient to
+ * extend the write to cover the entire page in order to avoid fragmentation
+ * inefficiencies.
+ *
+ * If the file is opened for synchronous writes or if we have a write delegation
+ * from the server then we can just skip the rest of the checks.
+ */
+static int nfs_can_extend_write(struct file *file, struct page *page, struct inode *inode)
+{
+ if (file->f_flags & O_DSYNC)
+ return 0;
+ if (nfs_have_delegation(inode, FMODE_WRITE))
+ return 1;
+ if (nfs_write_pageuptodate(page, inode) && (inode->i_flock == NULL ||
+ (inode->i_flock->fl_start == 0 &&
+ inode->i_flock->fl_end == OFFSET_MAX &&
+ inode->i_flock->fl_type != F_RDLCK)))
+ return 1;
+ return 0;
+}
+
/*
* Update and possibly write a cached page of an NFS file.
*
@@ -908,14 +930,7 @@ int nfs_updatepage(struct file *file, struct page *page,
file->f_path.dentry->d_name.name, count,
(long long)(page_file_offset(page) + offset));
- /* If we're not using byte range locks, and we know the page
- * is up to date, it may be more efficient to extend the write
- * to cover the entire page in order to avoid fragmentation
- * inefficiencies.
- */
- if (nfs_write_pageuptodate(page, inode) &&
- inode->i_flock == NULL &&
- !(file->f_flags & O_DSYNC)) {
+ if (nfs_can_extend_write(file, page, inode)) {
count = max(count + offset, nfs_page_length(page));
offset = 0;
}
--
1.7.11.7
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