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| author | Jan Kara <[email protected]> | 2012-06-12 14:20:37 +0000 |
|---|---|---|
| committer | Al Viro <[email protected]> | 2012-07-31 05:45:47 +0000 |
| commit | 14da9200140f8d722ad1767dfabadebd8b34f2ad (patch) | |
| tree | ea5d88b091999f7a64af0b9d335d7cad4c79edfb /net/unix/af_unix.c | |
| parent | fs: Skip atime update on frozen filesystem (diff) | |
| download | kernel-14da9200140f8d722ad1767dfabadebd8b34f2ad.tar.gz kernel-14da9200140f8d722ad1767dfabadebd8b34f2ad.zip | |
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 <[email protected]>
Tested-by: Peter M. Petrakis <[email protected]>
Tested-by: Dann Frazier <[email protected]>
Tested-by: Massimo Morana <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Al Viro <[email protected]>
Diffstat (limited to 'net/unix/af_unix.c')
0 files changed, 0 insertions, 0 deletions