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Message-Id: <1415313426-9622-72-git-send-email-kamal@canonical.com>
Date:	Thu,  6 Nov 2014 14:35:35 -0800
From:	Kamal Mostafa <kamal@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Dmitry Monakhov <dmonakhov@...nvz.org>,
	Theodore Ts'o <tytso@....edu>,
	Kamal Mostafa <kamal@...onical.com>
Subject: [PATCH 3.13 071/162] ext4: move error report out of atomic context in ext4_init_block_bitmap()

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

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

From: Dmitry Monakhov <dmonakhov@...nvz.org>

commit aef4885ae14f1df75b58395c5314d71f613d26d9 upstream.

Error report likely result in IO so it is bad idea to do it from
atomic context.

This patch should fix following issue:

BUG: sleeping function called from invalid context at include/linux/buffer_head.h:349
in_atomic(): 1, irqs_disabled(): 0, pid: 137, name: kworker/u128:1
5 locks held by kworker/u128:1/137:
 #0:  ("writeback"){......}, at: [<ffffffff81085618>] process_one_work+0x228/0x4d0
 #1:  ((&(&wb->dwork)->work)){......}, at: [<ffffffff81085618>] process_one_work+0x228/0x4d0
 #2:  (jbd2_handle){......}, at: [<ffffffff81242622>] start_this_handle+0x712/0x7b0
 #3:  (&ei->i_data_sem){......}, at: [<ffffffff811fa387>] ext4_map_blocks+0x297/0x430
 #4:  (&(&bgl->locks[i].lock)->rlock){......}, at: [<ffffffff811f3180>] ext4_read_block_bitmap_nowait+0x5d0/0x630
CPU: 3 PID: 137 Comm: kworker/u128:1 Not tainted 3.17.0-rc2-00184-g82752e4 #165
Hardware name: Intel Corporation W2600CR/W2600CR, BIOS SE5C600.86B.99.99.x028.061320111235 06/13/2011
Workqueue: writeback bdi_writeback_workfn (flush-1:0)
 0000000000000411 ffff880813777288 ffffffff815c7fdc ffff880813777288
 ffff880813a8bba0 ffff8808137772a8 ffffffff8108fb30 ffff880803e01e38
 ffff880803e01e38 ffff8808137772c8 ffffffff811a8d53 ffff88080ecc6000
Call Trace:
 [<ffffffff815c7fdc>] dump_stack+0x51/0x6d
 [<ffffffff8108fb30>] __might_sleep+0xf0/0x100
 [<ffffffff811a8d53>] __sync_dirty_buffer+0x43/0xe0
 [<ffffffff811a8e03>] sync_dirty_buffer+0x13/0x20
 [<ffffffff8120f581>] ext4_commit_super+0x1d1/0x230
 [<ffffffff8120fa03>] save_error_info+0x23/0x30
 [<ffffffff8120fd06>] __ext4_error+0xb6/0xd0
 [<ffffffff8120f260>] ? ext4_group_desc_csum+0x140/0x190
 [<ffffffff811f2d8c>] ext4_read_block_bitmap_nowait+0x1dc/0x630
 [<ffffffff8122e23a>] ext4_mb_init_cache+0x21a/0x8f0
 [<ffffffff8113ae95>] ? lru_cache_add+0x55/0x60
 [<ffffffff8112e16c>] ? add_to_page_cache_lru+0x6c/0x80
 [<ffffffff8122eaa0>] ext4_mb_init_group+0x190/0x280
 [<ffffffff8122ec51>] ext4_mb_good_group+0xc1/0x190
 [<ffffffff8123309a>] ext4_mb_regular_allocator+0x17a/0x410
 [<ffffffff8122c821>] ? ext4_mb_use_preallocated+0x31/0x380
 [<ffffffff81233535>] ? ext4_mb_new_blocks+0x205/0x8e0
 [<ffffffff8116ed5c>] ? kmem_cache_alloc+0xfc/0x180
 [<ffffffff812335b0>] ext4_mb_new_blocks+0x280/0x8e0
 [<ffffffff8116f2c4>] ? __kmalloc+0x144/0x1c0
 [<ffffffff81221797>] ? ext4_find_extent+0x97/0x320
 [<ffffffff812257f4>] ext4_ext_map_blocks+0xbc4/0x1050
 [<ffffffff811fa387>] ? ext4_map_blocks+0x297/0x430
 [<ffffffff811fa3ab>] ext4_map_blocks+0x2bb/0x430
 [<ffffffff81200e43>] ? ext4_init_io_end+0x23/0x50
 [<ffffffff811feb44>] ext4_writepages+0x564/0xaf0
 [<ffffffff815cde3b>] ? _raw_spin_unlock+0x2b/0x40
 [<ffffffff810ac7bd>] ? lock_release_non_nested+0x2fd/0x3c0
 [<ffffffff811a009e>] ? writeback_sb_inodes+0x10e/0x490
 [<ffffffff811a009e>] ? writeback_sb_inodes+0x10e/0x490
 [<ffffffff811377e3>] do_writepages+0x23/0x40
 [<ffffffff8119c8ce>] __writeback_single_inode+0x9e/0x280
 [<ffffffff811a026b>] writeback_sb_inodes+0x2db/0x490
 [<ffffffff811a0664>] wb_writeback+0x174/0x2d0
 [<ffffffff810ac359>] ? lock_release_holdtime+0x29/0x190
 [<ffffffff811a0863>] wb_do_writeback+0xa3/0x200
 [<ffffffff811a0a40>] bdi_writeback_workfn+0x80/0x230
 [<ffffffff81085618>] ? process_one_work+0x228/0x4d0
 [<ffffffff810856cd>] process_one_work+0x2dd/0x4d0
 [<ffffffff81085618>] ? process_one_work+0x228/0x4d0
 [<ffffffff81085c1d>] worker_thread+0x35d/0x460
 [<ffffffff810858c0>] ? process_one_work+0x4d0/0x4d0
 [<ffffffff810858c0>] ? process_one_work+0x4d0/0x4d0
 [<ffffffff8108a885>] kthread+0xf5/0x100
 [<ffffffff810990e5>] ? local_clock+0x25/0x30
 [<ffffffff8108a790>] ? __init_kthread_worker+0x70/0x70
 [<ffffffff815ce2ac>] ret_from_fork+0x7c/0xb0
 [<ffffffff8108a790>] ? __init_kthread_work

Signed-off-by: Dmitry Monakhov <dmonakhov@...nvz.org>
Signed-off-by: Theodore Ts'o <tytso@....edu>
[ kamal: backport to 3.13-stable: also make ext4_init_block_bitmap static,
  as per c197855ea ]
Signed-off-by: Kamal Mostafa <kamal@...onical.com>
---
 fs/ext4/balloc.c | 13 +++++++++----
 fs/ext4/ext4.h   |  4 ----
 2 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 6ea7b14..c8c3cb2 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -176,7 +176,8 @@ static unsigned int num_clusters_in_group(struct super_block *sb,
 }
 
 /* Initializes an uninitialized block bitmap */
-void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
+static int ext4_init_block_bitmap(struct super_block *sb,
+			    struct buffer_head *bh,
 			    ext4_group_t block_group,
 			    struct ext4_group_desc *gdp)
 {
@@ -191,11 +192,10 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 	/* If checksum is bad mark all blocks used to prevent allocation
 	 * essentially implementing a per-group read-only flag. */
 	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
-		ext4_error(sb, "Checksum bad for group %u", block_group);
 		grp = ext4_get_group_info(sb, block_group);
 		set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state);
 		set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state);
-		return;
+		return -EIO;
 	}
 	memset(bh->b_data, 0, sb->s_blocksize);
 
@@ -233,6 +233,7 @@ void ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 			     sb->s_blocksize * 8, bh->b_data);
 	ext4_block_bitmap_csum_set(sb, block_group, gdp, bh);
 	ext4_group_desc_csum_set(sb, block_group, gdp);
+	return 0;
 }
 
 /* Return the number of free blocks in a block group.  It is used when
@@ -419,11 +420,15 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group)
 	}
 	ext4_lock_group(sb, block_group);
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
-		ext4_init_block_bitmap(sb, bh, block_group, desc);
+		int err;
+
+		err = ext4_init_block_bitmap(sb, bh, block_group, desc);
 		set_bitmap_uptodate(bh);
 		set_buffer_uptodate(bh);
 		ext4_unlock_group(sb, block_group);
 		unlock_buffer(bh);
+		if (err)
+			ext4_error(sb, "Checksum bad for grp %u", block_group);
 		return bh;
 	}
 	ext4_unlock_group(sb, block_group);
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 0e9930f..5b250fe 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1979,10 +1979,6 @@ extern int ext4_wait_block_bitmap(struct super_block *sb,
 				  struct buffer_head *bh);
 extern struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
 						  ext4_group_t block_group);
-extern void ext4_init_block_bitmap(struct super_block *sb,
-				   struct buffer_head *bh,
-				   ext4_group_t group,
-				   struct ext4_group_desc *desc);
 extern unsigned ext4_free_clusters_after_init(struct super_block *sb,
 					      ext4_group_t block_group,
 					      struct ext4_group_desc *gdp);
-- 
1.9.1

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