diff options
| author | Jan Kara <jack@suse.cz> | 2012-06-12 16:20:37 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-07-31 09:45:47 +0400 |
| commit | 14da9200140f8d722ad1767dfabadebd8b34f2ad (patch) | |
| tree | ea5d88b091999f7a64af0b9d335d7cad4c79edfb /lib/random32.c | |
| parent | 5d37e9e6dec65cd21be68ee92de99686213e916b (diff) | |
fs: Protect write paths by sb_start_write - sb_end_write
There are several entry points which dirty pages in a filesystem. mmap
(handled by block_page_mkwrite()), buffered write (handled by
__generic_file_aio_write()), splice write (generic_file_splice_write),
truncate, and fallocate (these can dirty last partial page - handled inside
each filesystem separately). Protect these places with sb_start_write() and
sb_end_write().
->page_mkwrite() calls are particularly complex since they are called with
mmap_sem held and thus we cannot use standard sb_start_write() due to lock
ordering constraints. We solve the problem by using a special freeze protection
sb_start_pagefault() which ranks below mmap_sem.
BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib/random32.c')
0 files changed, 0 insertions, 0 deletions