| commit | 3317039c0dffe590f6e8256a9d3bfc11758a9091 | |
| author | J. R. Okajima <hooanon05@yahoo.co.jp> | |
| Wed, 9 Nov 2011 12:21:18 +0000 (9 21:21 +0900) | ||
| committer | Jan Alexander Steffens (heftig) <jan.steffens@gmail.com> | |
| Tue, 20 Mar 2012 10:05:52 +0000 (20 11:05 +0100) | ||
| tree | 128d7a2996b432a7666ac07af448c883bb6a2e9b | treesnapshot (tar.gz zip) |
| parent | 52f42edac0f146590f5f5be246e19850e525fddd | commitdiff |
aufs: bugfix mmap_sem 1/4, release [fdi]i_rwsem in file I/O
mmap(2) acquires mm->mmap_sem before ->mmap(), and aufs mmap() acquires
aufs rwsem. On the other hand, aufs file I/O functions including
->read(), ->write() acquire aufs rwsem and then mmap_sem.
This AB-BA problem will cause deadlock.
By this commit, aufs file I/O functions release aufs rwsem before
mmap_sem except si_rwsem. Holding si_rwsem is necessary to protect the
operation from aufs branch management.
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
(cherry picked from commit 0a118fbd1867734fbe1cf1a54907b0150fe9e1b4)
mmap(2) acquires mm->mmap_sem before ->mmap(), and aufs mmap() acquires
aufs rwsem. On the other hand, aufs file I/O functions including
->read(), ->write() acquire aufs rwsem and then mmap_sem.
This AB-BA problem will cause deadlock.
By this commit, aufs file I/O functions release aufs rwsem before
mmap_sem except si_rwsem. Holding si_rwsem is necessary to protect the
operation from aufs branch management.
Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
(cherry picked from commit 0a118fbd1867734fbe1cf1a54907b0150fe9e1b4)
| fs/aufs/f_op.c | diffblobblamehistory |