63 lines
2.1 KiB
Diff
63 lines
2.1 KiB
Diff
BZ 742091
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https://bugzilla.redhat.com/show_bug.cgi?id=742091
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This bug was never properly fixed upstream since the code got
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reorganized in:
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667eff35a1f56fa74ce98a0c7c29a40adc1ba4e3 ext4: reimplement convert and
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split_unwritten
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This fix has proposed by Zheng Liu <wenqing.lz@taobao.com>, then updated,
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reviewed and tested by me.
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We will meet with a BUG_ON() if following script is run.
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mkfs.ext4 -b 4096 /dev/sdb1 1000000
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mount -t ext4 /dev/sdb1 /mnt/sdb1
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fallocate -l 100M /mnt/sdb1/test
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sync
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for((i=0;i<170;i++))
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do
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dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 seek=`expr $i \* 2`
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done
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umount /mnt/sdb1
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mount -t ext4 /dev/sdb1 /mnt/sdb1
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dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 seek=341
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umount /mnt/sdb1
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mount /dev/sdb1 /mnt/sdb1
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dd if=/dev/zero of=/mnt/sdb1/test conv=notrunc bs=256k count=1 seek=340
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sync
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The reason is that it forgot to mark dirty when splitting two extents in
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ext4_ext_convert_to_initialized(). Althrough ex has been updated in memory,
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it is not dirtied both in ext4_ext_convert_to_initialized() and
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ext4_ext_insert_extent(). The disk layout is corrupted. Then it will meet with
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a BUG_ON() when writting at the start of that extent again.
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Originally-from: Zheng Liu <wenqing.lz@taobao.com>
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Signed-off-by: Lukas Czerner <lczerner@redhat.com>
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---
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fs/ext4/extents.c | 2 ++
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1 files changed, 2 insertions(+), 0 deletions(-)
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Index: linux-2.6.35.noarch/fs/ext4/extents.c
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===================================================================
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--- linux-2.6.35.noarch.orig/fs/ext4/extents.c
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+++ linux-2.6.35.noarch/fs/ext4/extents.c
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@@ -2687,6 +2687,7 @@ static int ext4_ext_convert_to_initializ
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ex1 = ex;
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ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
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ext4_ext_mark_uninitialized(ex1);
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+ ext4_ext_dirty(handle, inode, path + depth);
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ex2 = &newex;
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}
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/*
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@@ -2850,6 +2851,7 @@ static int ext4_ext_convert_to_initializ
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ex1 = ex;
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ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
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ext4_ext_mark_uninitialized(ex1);
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+ ext4_ext_dirty(handle, inode, path + depth);
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ex2 = &newex;
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}
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/* ex2: map->m_lblk to map->m_lblk + maxblocks-1 : initialised */
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