| From 25e65c388a1b7d4163e12289c070b5da0cc933c9 Mon Sep 17 00:00:00 2001 |
| From: Akira Fujita <a-fujita@rs.jp.nec.com> |
| Date: Mon, 23 Nov 2009 07:24:41 -0500 |
| Subject: [PATCH 61/85] ext4: fix possible recursive locking warning in EXT4_IOC_MOVE_EXT |
| |
| (cherry picked from commit 49bd22bc4d603a2a4fc2a6a60e156cbea52eb494) |
| |
| If CONFIG_PROVE_LOCKING is enabled, the double_down_write_data_sem() |
| will trigger a false-positive warning of a recursive lock. Since we |
| take i_data_sem for the two inodes ordered by their inode numbers, |
| this isn't a problem. Use of down_write_nested() will notify the lock |
| dependency checker machinery that there is no problem here. |
| |
| This problem was reported by Brian Rogers: |
| |
| http://marc.info/?l=linux-ext4&m=125115356928011&w=1 |
| |
| Reported-by: Brian Rogers <brian@xyzw.org> |
| Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com> |
| Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| --- |
| fs/ext4/move_extent.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/ext4/move_extent.c |
| +++ b/fs/ext4/move_extent.c |
| @@ -189,7 +189,7 @@ double_down_write_data_sem(struct inode |
| } |
| |
| down_write(&EXT4_I(first)->i_data_sem); |
| - down_write(&EXT4_I(second)->i_data_sem); |
| + down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING); |
| } |
| |
| /** |
