[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>

16 files changed, 48 insertions, 61 deletions

diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 57a43b8feef5..17089d1905ff 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -193,8 +193,7 @@ int v9fs_dir_release(struct inode *inode, struct file *filp)
                 fid->fid);
         fidnum = fid->fid;
 
-        filemap_fdatawrite(inode->i_mapping);
-        filemap_fdatawait(inode->i_mapping);
+        filemap_write_and_wait(inode->i_mapping);
 
         if (fidnum >= 0) {
                 dprintk(DEBUG_VFS, "fidopen: %d v9f->fid: %d\n", fid->fidopen,
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index 89c849da8504..e13577da9130 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -165,8 +165,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
                 return -ENOLCK;
 
         if ((IS_SETLK(cmd) || IS_SETLKW(cmd)) && fl->fl_type != F_UNLCK) {
-                filemap_fdatawrite(inode->i_mapping);
-                filemap_fdatawait(inode->i_mapping);
+                filemap_write_and_wait(inode->i_mapping);
                 invalidate_inode_pages(&inode->i_data);
         }
 
diff --git a/fs/buffer.c b/fs/buffer.c
index 55023231e460..263df0f192aa 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -153,14 +153,8 @@ int sync_blockdev(struct block_device *bdev)
 {
         int ret = 0;
 
-        if (bdev) {
-                int err;
-
-                ret = filemap_fdatawrite(bdev->bd_inode->i_mapping);
-                err = filemap_fdatawait(bdev->bd_inode->i_mapping);
-                if (!ret)
-                        ret = err;
-        }
+        if (bdev)
+                ret = filemap_write_and_wait(bdev->bd_inode->i_mapping);
         return ret;
 }
 EXPORT_SYMBOL(sync_blockdev);
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;
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 411c1f7f84da..9558f51bca55 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -1148,8 +1148,7 @@ int cifs_setattr(struct dentry *direntry, struct iattr *attrs)
         /* BB check if we need to refresh inode from server now ? BB */
 
         /* need to flush data before changing file size on server */
-        filemap_fdatawrite(direntry->d_inode->i_mapping);
-        filemap_fdatawait(direntry->d_inode->i_mapping);
+        filemap_write_and_wait(direntry->d_inode->i_mapping);
 
         if (attrs->ia_valid & ATTR_SIZE) {
                 /* To avoid spurious oplock breaks from server, in the case of
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 68000a50ceb6..2967b7393415 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -302,8 +302,7 @@ int dbSync(struct inode *ipbmap)
         /*
          * write out dirty pages of bmap
          */
-        filemap_fdatawrite(ipbmap->i_mapping);
-        filemap_fdatawait(ipbmap->i_mapping);
+        filemap_write_and_wait(ipbmap->i_mapping);
 
         diWriteSpecial(ipbmap, 0);
 
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 28201b194f53..31b4aa13dd4b 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -265,8 +265,7 @@ int diSync(struct inode *ipimap)
         /*
          * write out dirty pages of imap
          */
-        filemap_fdatawrite(ipimap->i_mapping);
-        filemap_fdatawait(ipimap->i_mapping);
+        filemap_write_and_wait(ipimap->i_mapping);
 
         diWriteSpecial(ipimap, 0);
 
@@ -565,8 +564,7 @@ void diFreeSpecial(struct inode *ip)
                 jfs_err("diFreeSpecial called with NULL ip!");
                 return;
         }
-        filemap_fdatawrite(ip->i_mapping);
-        filemap_fdatawait(ip->i_mapping);
+        filemap_write_and_wait(ip->i_mapping);
         truncate_inode_pages(ip->i_mapping, 0);
         iput(ip);
 }
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c
index b660c93c92de..2ddb6b892bcf 100644
--- a/fs/jfs/jfs_txnmgr.c
+++ b/fs/jfs/jfs_txnmgr.c
@@ -1231,10 +1231,8 @@ int txCommit(tid_t tid,		/* transaction identifier */
                  * when we don't need to worry about it at all.
                  *
                  * if ((!S_ISDIR(ip->i_mode))
-                 *    && (tblk->flag & COMMIT_DELETE) == 0) {
-                 *      filemap_fdatawrite(ip->i_mapping);
-                 *      filemap_fdatawait(ip->i_mapping);
-                 * }
+                 *    && (tblk->flag & COMMIT_DELETE) == 0)
+                 *      filemap_write_and_wait(ip->i_mapping);
                  */
 
                 /*
diff --git a/fs/jfs/jfs_umount.c b/fs/jfs/jfs_umount.c
index 5cf91785b541..21eaf7ac0fcb 100644
--- a/fs/jfs/jfs_umount.c
+++ b/fs/jfs/jfs_umount.c
@@ -108,8 +108,7 @@ int jfs_umount(struct super_block *sb)
          * Make sure all metadata makes it to disk before we mark
          * the superblock as clean
          */
-        filemap_fdatawrite(sbi->direct_inode->i_mapping);
-        filemap_fdatawait(sbi->direct_inode->i_mapping);
+        filemap_write_and_wait(sbi->direct_inode->i_mapping);
 
         /*
          * ensure all file system file pages are propagated to their
@@ -161,8 +160,7 @@ int jfs_umount_rw(struct super_block *sb)
          * mark the superblock clean before everything is flushed to
          * disk.
          */
-        filemap_fdatawrite(sbi->direct_inode->i_mapping);
-        filemap_fdatawait(sbi->direct_inode->i_mapping);
+        filemap_write_and_wait(sbi->direct_inode->i_mapping);
 
         updateSuper(sb, FM_CLEAN);
 
diff --git a/fs/jfs/resize.c b/fs/jfs/resize.c
index c6dc254d3253..45180361871c 100644
--- a/fs/jfs/resize.c
+++ b/fs/jfs/resize.c
@@ -376,8 +376,7 @@ int jfs_extendfs(struct super_block *sb, s64 newLVSize, int newLogSize)
          * by txCommit();
          */
         filemap_fdatawait(ipbmap->i_mapping);
-        filemap_fdatawrite(ipbmap->i_mapping);
-        filemap_fdatawait(ipbmap->i_mapping);
+        filemap_write_and_wait(ipbmap->i_mapping);
         diWriteSpecial(ipbmap, 0);
 
         newPage = nPages;       /* first new page number */
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 4226af3ea91b..8d31f1336431 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -502,8 +502,7 @@ out_no_rw:
                 jfs_err("jfs_umount failed with return code %d", rc);
         }
 out_mount_failed:
-        filemap_fdatawrite(sbi->direct_inode->i_mapping);
-        filemap_fdatawait(sbi->direct_inode->i_mapping);
+        filemap_write_and_wait(sbi->direct_inode->i_mapping);
         truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
         make_bad_inode(sbi->direct_inode);
         iput(sbi->direct_inode);
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index e7bd0d92600f..3e4ba9cb7f80 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -644,10 +644,7 @@ int nfs_sync_mapping(struct address_space *mapping)
         if (mapping->nrpages == 0)
                 return 0;
         unmap_mapping_range(mapping, 0, 0, 0);
-        ret = filemap_fdatawrite(mapping);
-        if (ret != 0)
-                goto out;
-        ret = filemap_fdatawait(mapping);
+        ret = filemap_write_and_wait(mapping);
         if (ret != 0)
                 goto out;
         ret = nfs_wb_all(mapping->host);
@@ -864,8 +861,7 @@ nfs_setattr(struct dentry *dentry, struct iattr *attr)
         nfs_begin_data_update(inode);
         /* Write all dirty data if we're changing file permissions or size */
         if ((attr->ia_valid & (ATTR_MODE|ATTR_UID|ATTR_GID|ATTR_SIZE)) != 0) {
-                if (filemap_fdatawrite(inode->i_mapping) == 0)
-                        filemap_fdatawait(inode->i_mapping);
+                filemap_write_and_wait(inode->i_mapping);
                 nfs_wb_all(inode);
         }
         /*
diff --git a/fs/smbfs/file.c b/fs/smbfs/file.c
index b4fcfa8b55a1..3c6eb3ba718e 100644
--- a/fs/smbfs/file.c
+++ b/fs/smbfs/file.c
@@ -374,8 +374,7 @@ smb_file_release(struct inode *inode, struct file * file)
                 /* We must flush any dirty pages now as we won't be able to
                    write anything after close. mmap can trigger this.
                    "openers" should perhaps include mmap'ers ... */
-                filemap_fdatawrite(inode->i_mapping);
-                filemap_fdatawait(inode->i_mapping);
+                filemap_write_and_wait(inode->i_mapping);
                 smb_close(inode);
         }
         unlock_kernel();
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 10b994428fef..6ec88bf59b2d 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -697,8 +697,7 @@ smb_notify_change(struct dentry *dentry, struct iattr *attr)
                         DENTRY_PATH(dentry),
                         (long) inode->i_size, (long) attr->ia_size);
 
-                filemap_fdatawrite(inode->i_mapping);
-                filemap_fdatawait(inode->i_mapping);
+                filemap_write_and_wait(inode->i_mapping);
 
                 error = smb_open(dentry, O_WRONLY);
                 if (error)
diff --git a/fs/xfs/linux-2.6/xfs_fs_subr.c b/fs/xfs/linux-2.6/xfs_fs_subr.c
index f89340c61bf2..4fa4b1a5187e 100644
--- a/fs/xfs/linux-2.6/xfs_fs_subr.c
+++ b/fs/xfs/linux-2.6/xfs_fs_subr.c
@@ -79,8 +79,7 @@ fs_flushinval_pages(
         struct inode    *ip = LINVFS_GET_IP(vp);
 
         if (VN_CACHED(vp)) {
-                filemap_fdatawrite(ip->i_mapping);
-                filemap_fdatawait(ip->i_mapping);
+                filemap_write_and_wait(ip->i_mapping);
 
                 truncate_inode_pages(ip->i_mapping, first);
         }
diff --git a/mm/filemap.c b/mm/filemap.c
index 8fdf36508023..478f4c74cc31 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -343,30 +343,44 @@ EXPORT_SYMBOL(filemap_fdatawait);
 
 int filemap_write_and_wait(struct address_space *mapping)
 {
-        int retval = 0;
+        int err = 0;
 
         if (mapping->nrpages) {
-                retval = filemap_fdatawrite(mapping);
-                if (retval == 0)
-                        retval = filemap_fdatawait(mapping);
+                err = filemap_fdatawrite(mapping);
+                /*
+                 * Even if the above returned error, the pages may be
+                 * written partially (e.g. -ENOSPC), so we wait for it.
+                 * But the -EIO is special case, it may indicate the worst
+                 * thing (e.g. bug) happened, so we avoid waiting for it.
+                 */
+                if (err != -EIO) {
+                        int err2 = filemap_fdatawait(mapping);
+                        if (!err)
+                                err = err2;
+                }
         }
-        return retval;
+        return err;
 }
+EXPORT_SYMBOL(filemap_write_and_wait);
 
 int filemap_write_and_wait_range(struct address_space *mapping,
                                  loff_t lstart, loff_t lend)
 {
-        int retval = 0;
+        int err = 0;
 
         if (mapping->nrpages) {
-                retval = __filemap_fdatawrite_range(mapping, lstart, lend,
-                                                    WB_SYNC_ALL);
-                if (retval == 0)
-                        retval = wait_on_page_writeback_range(mapping,
-                                                    lstart >> PAGE_CACHE_SHIFT,
-                                                    lend >> PAGE_CACHE_SHIFT);
+                err = __filemap_fdatawrite_range(mapping, lstart, lend,
+                                                 WB_SYNC_ALL);
+                /* See comment of filemap_write_and_wait() */
+                if (err != -EIO) {
+                        int err2 = wait_on_page_writeback_range(mapping,
+                                                lstart >> PAGE_CACHE_SHIFT,
+                                                lend >> PAGE_CACHE_SHIFT);
+                        if (!err)
+                                err = err2;
+                }
         }
-        return retval;
+        return err;
 }
 
 /*