[PATCH] Fix and add EXPORT_SYMBOL(filemap_write_and_wait)

This patch add EXPORT_SYMBOL(filemap_write_and_wait) and use it.

See mm/filemap.c:

And changes the filemap_write_and_wait() and filemap_write_and_wait_range().

Current filemap_write_and_wait() doesn't wait if filemap_fdatawrite()
returns error.  However, even if filemap_fdatawrite() returned an
error, it may have submitted the partially data pages to the device.
(e.g. in the case of -ENOSPC)

<quotation>
Andrew Morton writes,

If filemap_fdatawrite() returns an error, this might be due to some
I/O problem: dead disk, unplugged cable, etc.  Given the generally
crappy quality of the kernel's handling of such exceptions, there's a
good chance that the filemap_fdatawait() will get stuck in D state
forever.
</quotation>

So, this patch doesn't wait if filemap_fdatawrite() returns the -EIO.

Trond, could you please review the nfs part?  Especially I'm not sure,
nfs must use the "filemap_fdatawrite(inode->i_mapping) == 0", or not.

Acked-by: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 14a1c72ced92..5ade53d7bca8 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -127,8 +127,7 @@ static inline int cifs_open_inode_helper(struct inode *inode, struct file *file,
                 if (file->f_dentry->d_inode->i_mapping) {
                 /* BB no need to lock inode until after invalidate
                    since namei code should already have it locked? */
-                        filemap_fdatawrite(file->f_dentry->d_inode->i_mapping);
-                        filemap_fdatawait(file->f_dentry->d_inode->i_mapping);
+                        filemap_write_and_wait(file->f_dentry->d_inode->i_mapping);
                 }
                 cFYI(1, ("invalidating remote inode since open detected it "
                          "changed"));
@@ -419,8 +418,7 @@ static int cifs_reopen_file(struct inode *inode, struct file *file,
                 pCifsInode = CIFS_I(inode);
                 if (pCifsInode) {
                         if (can_flush) {
-                                filemap_fdatawrite(inode->i_mapping);
-                                filemap_fdatawait(inode->i_mapping);
+                                filemap_write_and_wait(inode->i_mapping);
                         /* temporarily disable caching while we
                            go to server to get inode info */
                                 pCifsInode->clientCanCacheAll = FALSE;