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00e5a55c BS |
1 | From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> |
2 | Date: Wed, 13 May 2009 22:36:58 +0000 (-0400) | |
3 | Subject: ext4: Fix sub-block zeroing for writes into preallocated extents | |
4 | Patch-mainline: 2.6.30 | |
5 | Git-commit: 9c1ee184a30394e54165fa4c15923cabd952c106 | |
6 | References: bnc#503161 | |
7 | ||
8 | ext4: Fix sub-block zeroing for writes into preallocated extents | |
9 | ||
10 | We need to mark the buffer_head mapping preallocated space as new | |
11 | during write_begin. Otherwise we don't zero out the page cache content | |
12 | properly for a partial write. This will cause file corruption with | |
13 | preallocation. | |
14 | ||
15 | Now that we mark the buffer_head new we also need to have a valid | |
16 | buffer_head blocknr so that unmap_underlying_metadata() unmaps the | |
17 | correct block. | |
18 | ||
19 | Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | |
20 | Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> | |
21 | Acked-by: Jeff Mahoney <jeffm@suse.com> | |
22 | --- | |
23 | ||
24 | fs/ext4/extents.c | 2 ++ | |
25 | fs/ext4/inode.c | 7 +++++++ | |
26 | 2 files changed, 9 insertions(+) | |
27 | ||
28 | --- a/fs/ext4/extents.c | |
29 | +++ b/fs/ext4/extents.c | |
30 | @@ -2664,6 +2664,8 @@ int ext4_ext_get_blocks(handle_t *handle | |
31 | if (allocated > max_blocks) | |
32 | allocated = max_blocks; | |
33 | set_buffer_unwritten(bh_result); | |
34 | + bh_result->b_bdev = inode->i_sb->s_bdev; | |
35 | + bh_result->b_blocknr = newblock; | |
36 | goto out2; | |
37 | } | |
38 | ||
39 | --- a/fs/ext4/inode.c | |
40 | +++ b/fs/ext4/inode.c | |
41 | @@ -2220,6 +2220,13 @@ static int ext4_da_get_block_prep(struct | |
42 | set_buffer_delay(bh_result); | |
43 | } else if (ret > 0) { | |
44 | bh_result->b_size = (ret << inode->i_blkbits); | |
45 | + /* | |
46 | + * With sub-block writes into unwritten extents | |
47 | + * we also need to mark the buffer as new so that | |
48 | + * the unwritten parts of the buffer gets correctly zeroed. | |
49 | + */ | |
50 | + if (buffer_unwritten(bh_result)) | |
51 | + set_buffer_new(bh_result); | |
52 | ret = 0; | |
53 | } | |
54 |