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From: Eric Sandeen <sandeen@redhat.com>
To: ext4 development <linux-ext4@vger.kernel.org>
Subject: [PATCH] down i_data_sem only for read when walking tree for fiemap
Date: Fri, 15 May 2009 16:07:32 -0500	[thread overview]
Message-ID: <4A0DD994.1090200@redhat.com> (raw)

Not sure why I put this in as down_write originally; all we are
doing is walking the tree, nothing will change under us and
concurrent reads should be no problem.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

Index: linux-2.6/fs/ext4/extents.c
===================================================================
--- linux-2.6.orig/fs/ext4/extents.c
+++ linux-2.6/fs/ext4/extents.c
@@ -3309,10 +3309,10 @@ int ext4_fiemap(struct inode *inode, str
 		 * Walk the extent tree gathering extent information.
 		 * ext4_ext_fiemap_cb will push extents back to user.
 		 */
-		down_write(&EXT4_I(inode)->i_data_sem);
+		down_read(&EXT4_I(inode)->i_data_sem);
 		error = ext4_ext_walk_space(inode, start_blk, len_blks,
 					  ext4_ext_fiemap_cb, fieinfo);
-		up_write(&EXT4_I(inode)->i_data_sem);
+		up_read(&EXT4_I(inode)->i_data_sem);
 	}
 
 	return error;



             reply	other threads:[~2009-05-15 21:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-15 21:07 Eric Sandeen [this message]
2009-05-18  3:37 ` [PATCH] down i_data_sem only for read when walking tree for fiemap Theodore Tso

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