PWN-Hunter/android_kernel_xiaomi_sdm845
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ext4: Don't look at buffer_heads outside i_size.

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Buffer heads outside i_size will be unmapped. So when we
are doing "walk_page_buffers" limit ourself to i_size.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Josef Bacik <jbacik@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
----
This commit is contained in:
Aneesh Kumar K.V 2009-06-04 08:06:06 -04:00 committed by Theodore Ts'o
parent e6462869e4
commit b767e78a17
1 changed files with 16 additions and 12 deletions
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28
fs/ext4/inode.c
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@ -2578,7 +2578,7 @@ static int ext4_da_writepage(struct page *page,
* all are mapped and non delay. We don't want to
* do block allocation here.
*/
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
ret = block_prepare_write(page, 0, len,
noalloc_get_block_write);
if (!ret) {
page_bufs = page_buffers(page);
@ -2600,7 +2600,7 @@ static int ext4_da_writepage(struct page *page,
return 0;
}
/* now mark the buffer_heads as dirty and uptodate */
block_commit_write(page, 0, PAGE_CACHE_SIZE);
block_commit_write(page, 0, len);
}
if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
@ -3246,6 +3246,8 @@ static int ext4_normal_writepage(struct page *page,
static int __ext4_journalled_writepage(struct page *page,
struct writeback_control *wbc)
{
loff_t size;
unsigned int len;
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
struct buffer_head *page_bufs;
@ -3253,14 +3255,17 @@ static int __ext4_journalled_writepage(struct page *page,
int ret = 0;
int err;
ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
noalloc_get_block_write);
size = i_size_read(inode);
if (page->index == size >> PAGE_CACHE_SHIFT)
len = size & ~PAGE_CACHE_MASK;
else
len = PAGE_CACHE_SIZE;
ret = block_prepare_write(page, 0, len, noalloc_get_block_write);
if (ret != 0)
goto out_unlock;
page_bufs = page_buffers(page);
walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
bget_one);
walk_page_buffers(handle, page_bufs, 0, len, NULL, bget_one);
/* As soon as we unlock the page, it can go away, but we have
* references to buffers so we are safe */
unlock_page(page);
@ -3271,19 +3276,18 @@ static int __ext4_journalled_writepage(struct page *page,
goto out;
}
ret = walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
ret = walk_page_buffers(handle, page_bufs, 0, len, NULL,
do_journal_get_write_access);
err = walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, write_end_fn);
err = walk_page_buffers(handle, page_bufs, 0, len, NULL,
write_end_fn);
if (ret == 0)
ret = err;
err = ext4_journal_stop(handle);
if (!ret)
ret = err;
walk_page_buffers(handle, page_bufs, 0,
PAGE_CACHE_SIZE, NULL, bput_one);
walk_page_buffers(handle, page_bufs, 0, len, NULL, bput_one);
EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
goto out;