| Message ID | 1448931215-51572-1-git-send-email-jaegeuk@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Jaegeuk,
[auto build test WARNING on: f2fs/dev]
[also build test WARNING on: v4.4-rc3 next-20151127]
url: https://github.com/0day-ci/linux/commits/Jaegeuk-Kim/f2fs-avoid-deadlock-in-f2fs_shrink_extent_tree/20151201-085538
base: https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs dev
config: i386-randconfig-i1-201548 (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All warnings (new ones prefixed by >>):
fs/f2fs/extent_cache.c: In function 'f2fs_shrink_extent_tree':
>> fs/f2fs/extent_cache.c:618:27: warning: passing argument 1 of 'down_write_trylock' from incompatible pointer type [-Wincompatible-pointer-types]
if (down_write_trylock(&et->lock)) {
^
In file included from include/linux/fs.h:20:0,
from fs/f2fs/extent_cache.c:14:
include/linux/rwsem.h:123:12: note: expected 'struct rw_semaphore *' but argument is of type 'rwlock_t * {aka struct <anonymous> *}'
extern int down_write_trylock(struct rw_semaphore *sem);
^
vim +/down_write_trylock +618 fs/f2fs/extent_cache.c
602 }
603 spin_unlock(&sbi->extent_lock);
604
605 /*
606 * reset ino for searching victims from beginning of global extent tree.
607 */
608 ino = F2FS_ROOT_INO(sbi);
609
610 while ((found = radix_tree_gang_lookup(root,
611 (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
612 unsigned i;
613
614 ino = treevec[found - 1]->ino + 1;
615 for (i = 0; i < found; i++) {
616 struct extent_tree *et = treevec[i];
617
> 618 if (down_write_trylock(&et->lock)) {
619 node_cnt += __free_extent_tree(sbi, et, false);
620 write_unlock(&et->lock);
621 }
622
623 if (node_cnt + tree_cnt >= nr_shrink)
624 goto unlock_out;
625 }
626 }
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Jaegeuk,
[auto build test WARNING on: f2fs/dev]
[also build test WARNING on: v4.4-rc3 next-20151127]
url: https://github.com/0day-ci/linux/commits/Jaegeuk-Kim/f2fs-avoid-deadlock-in-f2fs_shrink_extent_tree/20151201-085538
base: https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs dev
config: x86_64-randconfig-s2-12010958 (attached as .config)
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
In file included from include/linux/linkage.h:4:0,
from include/linux/fs.h:4,
from fs/f2fs/extent_cache.c:14:
fs/f2fs/extent_cache.c: In function 'f2fs_shrink_extent_tree':
fs/f2fs/extent_cache.c:618:27: warning: passing argument 1 of 'down_write_trylock' from incompatible pointer type [-Wincompatible-pointer-types]
if (down_write_trylock(&et->lock)) {
^
include/linux/compiler.h:147:28: note: in definition of macro '__trace_if'
if (__builtin_constant_p((cond)) ? !!(cond) : \
^
>> fs/f2fs/extent_cache.c:618:4: note: in expansion of macro 'if'
if (down_write_trylock(&et->lock)) {
^
In file included from include/linux/fs.h:20:0,
from fs/f2fs/extent_cache.c:14:
include/linux/rwsem.h:123:12: note: expected 'struct rw_semaphore *' but argument is of type 'rwlock_t * {aka struct <anonymous> *}'
extern int down_write_trylock(struct rw_semaphore *sem);
^
In file included from include/linux/linkage.h:4:0,
from include/linux/fs.h:4,
from fs/f2fs/extent_cache.c:14:
fs/f2fs/extent_cache.c:618:27: warning: passing argument 1 of 'down_write_trylock' from incompatible pointer type [-Wincompatible-pointer-types]
if (down_write_trylock(&et->lock)) {
^
include/linux/compiler.h:147:40: note: in definition of macro '__trace_if'
if (__builtin_constant_p((cond)) ? !!(cond) : \
^
>> fs/f2fs/extent_cache.c:618:4: note: in expansion of macro 'if'
if (down_write_trylock(&et->lock)) {
^
In file included from include/linux/fs.h:20:0,
from fs/f2fs/extent_cache.c:14:
include/linux/rwsem.h:123:12: note: expected 'struct rw_semaphore *' but argument is of type 'rwlock_t * {aka struct <anonymous> *}'
extern int down_write_trylock(struct rw_semaphore *sem);
^
In file included from include/linux/linkage.h:4:0,
from include/linux/fs.h:4,
from fs/f2fs/extent_cache.c:14:
fs/f2fs/extent_cache.c:618:27: warning: passing argument 1 of 'down_write_trylock' from incompatible pointer type [-Wincompatible-pointer-types]
if (down_write_trylock(&et->lock)) {
^
include/linux/compiler.h:158:16: note: in definition of macro '__trace_if'
______r = !!(cond); \
^
>> fs/f2fs/extent_cache.c:618:4: note: in expansion of macro 'if'
if (down_write_trylock(&et->lock)) {
^
In file included from include/linux/fs.h:20:0,
from fs/f2fs/extent_cache.c:14:
include/linux/rwsem.h:123:12: note: expected 'struct rw_semaphore *' but argument is of type 'rwlock_t * {aka struct <anonymous> *}'
extern int down_write_trylock(struct rw_semaphore *sem);
^
vim +/if +618 fs/f2fs/extent_cache.c
602 }
603 spin_unlock(&sbi->extent_lock);
604
605 /*
606 * reset ino for searching victims from beginning of global extent tree.
607 */
608 ino = F2FS_ROOT_INO(sbi);
609
610 while ((found = radix_tree_gang_lookup(root,
611 (void **)treevec, ino, EXT_TREE_VEC_SIZE))) {
612 unsigned i;
613
614 ino = treevec[found - 1]->ino + 1;
615 for (i = 0; i < found; i++) {
616 struct extent_tree *et = treevec[i];
617
> 618 if (down_write_trylock(&et->lock)) {
619 node_cnt += __free_extent_tree(sbi, et, false);
620 write_unlock(&et->lock);
621 }
622
623 if (node_cnt + tree_cnt >= nr_shrink)
624 goto unlock_out;
625 }
626 }
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c index 7ddba81..21b1b8e 100644 --- a/fs/f2fs/extent_cache.c +++ b/fs/f2fs/extent_cache.c @@ -615,9 +615,10 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) for (i = 0; i < found; i++) { struct extent_tree *et = treevec[i]; - write_lock(&et->lock); - node_cnt += __free_extent_tree(sbi, et, false); - write_unlock(&et->lock); + if (down_write_trylock(&et->lock)) { + node_cnt += __free_extent_tree(sbi, et, false); + write_unlock(&et->lock); + } if (node_cnt + tree_cnt >= nr_shrink) goto unlock_out;
While handling extent trees, we can enter into a reclaiming path anytime. If it tries to release some extent nodes in the same extent tree, write_lock(&et->lock) would be hanged. In order to avoid the deadlock, we can just skip it. Note that, if it is an unreferenced tree, we should get write_lock(&et->lock) successfully and release all of therein nodes. Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> --- fs/f2fs/extent_cache.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)