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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2009-05-13 18:36:58 -0400
committerTheodore Ts'o <tytso@mit.edu>2009-05-13 18:36:58 -0400
commit9c1ee184a30394e54165fa4c15923cabd952c106 (patch)
tree77fee66ccc5e4aec3aeff7c7d641691b116be091
parent091bf7624d1c90cec9e578a18529f615213ff847 (diff)
ext4: Fix sub-block zeroing for writes into preallocated extents
We need to mark the buffer_head mapping preallocated space as new during write_begin. Otherwise we don't zero out the page cache content properly for a partial write. This will cause file corruption with preallocation. Now that we mark the buffer_head new we also need to have a valid buffer_head blocknr so that unmap_underlying_metadata() unmaps the correct block. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
-rw-r--r--fs/ext4/extents.c2
-rw-r--r--fs/ext4/inode.c7
2 files changed, 9 insertions, 0 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e4033215834..172656c2a3b 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2875,6 +2875,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
if (allocated > max_blocks)
allocated = max_blocks;
set_buffer_unwritten(bh_result);
+ bh_result->b_bdev = inode->i_sb->s_bdev;
+ bh_result->b_blocknr = newblock;
goto out2;
}
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e91f978c7f1..d4b634ae06b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2323,6 +2323,13 @@ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
set_buffer_delay(bh_result);
} else if (ret > 0) {
bh_result->b_size = (ret << inode->i_blkbits);
+ /*
+ * With sub-block writes into unwritten extents
+ * we also need to mark the buffer as new so that
+ * the unwritten parts of the buffer gets correctly zeroed.
+ */
+ if (buffer_unwritten(bh_result))
+ set_buffer_new(bh_result);
ret = 0;
}