xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

udf: fix possible leakage of blocks

Browse Source 
We have to take care that when we call udf_discard_prealloc() from
udf_clear_inode() we have to write inode ourselves afterwards (otherwise,
some changes might be lost leading to leakage of blocks, use of free blocks
or improperly aligned extents).

Also udf_discard_prealloc() does two different things - it removes
preallocated blocks and truncates the last extent to exactly match i_size.
We move the latter functionality to udf_truncate_tail_extent(), call
udf_discard_prealloc() when last reference to a file is dropped and call
udf_truncate_tail_extent() when inode is being removed from inode cache
(udf_clear_inode() call).

We cannot call udf_truncate_tail_extent() earlier as subsequent open+write
would find the last block of the file mapped and happily write to the end
of it, although the last extent says it's shorter.

[akpm@linux-foundation.org: Make checkpatch.pl happier]
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Eric Sandeen <sandeen@sandeen.net>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara
2007-06-16 10:16:14 -07:00
committed by Linus Torvalds
parent 4b356be019
commit 74584ae509
3 changed files with 77 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
fs/udf/inode.c
View File

@@ -100,14 +100,23 @@ no_delete:
clear_inode(inode);
}
/*
* If we are going to release inode from memory, we discard preallocation and
* truncate last inode extent to proper length. We could use drop_inode() but
* it's called under inode_lock and thus we cannot mark inode dirty there. We
* use clear_inode() but we have to make sure to write inode as it's not written
* automatically.
*/
void udf_clear_inode(struct inode *inode)
{
if (!(inode->i_sb->s_flags & MS_RDONLY)) {
lock_kernel();
/* Discard preallocation for directories, symlinks, etc. */
udf_discard_prealloc(inode);
udf_truncate_tail_extent(inode);
unlock_kernel();
write_inode_now(inode, 1);
}
kfree(UDF_I_DATA(inode));
UDF_I_DATA(inode) = NULL;
}