[ 16/42] jbd2: use GFP_NOFS for blkdev_issue_flush

From: Greg KH
Date: Tue Apr 24 2012 - 18:44:50 EST


3.0-stable review patch. If anyone has any objections, please let me know.

------------------

From: Shaohua Li <shli@xxxxxxxxxx>

commit 99aa78466777083255b876293e9e83dec7cd809a upstream.

flush request is issued in transaction commit code path, so looks using
GFP_KERNEL to allocate memory for flush request bio falls into the classic
deadlock issue. I saw btrfs and dm get it right, but ext4, xfs and md are
using GFP.

Signed-off-by: Shaohua Li <shli@xxxxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/jbd2/commit.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -683,7 +683,7 @@ start_journal_io:
if (commit_transaction->t_need_data_flush &&
(journal->j_fs_dev != journal->j_dev) &&
(journal->j_flags & JBD2_BARRIER))
- blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
+ blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);

/* Done it all: now write the commit record asynchronously. */
if (JBD2_HAS_INCOMPAT_FEATURE(journal,
@@ -819,7 +819,7 @@ wait_for_iobuf:
if (JBD2_HAS_INCOMPAT_FEATURE(journal,
JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
journal->j_flags & JBD2_BARRIER) {
- blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL);
+ blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
}

if (err)


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