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f2fs: avoid f2fs_lock_op for IPU writes 

Currently, if we do get_node_of_data before f2fs_lock_op, there may be dead lock
as follows, where process A would be in infinite loop, and B will NOT be awaked.

Process A(cp):            Process B:
f2fs_lock_all(sbi)
                        get_dnode_of_data <---- lock dn.node_page
flush_nodes             f2fs_lock_op

So, this patch adds f2fs_trylock_op to avoid f2fs_lock_op done by IPU.

Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim 2017-05-12 13:51:34 -07:00
parent a912b54d3a
commit cc15620bc8
4 changed files with 45 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
fs/f2fs/data.c
View File

@ -1383,12 +1383,12 @@ int do_write_data_page(struct f2fs_io_info *fio)
if (valid_ipu_blkaddr(fio)) {
ipu_force = true;
fio->need_lock = false;
fio->need_lock = LOCK_DONE;
goto got_it;
}
}
if (fio->need_lock)
if (fio->need_lock == LOCK_REQ)
f2fs_lock_op(fio->sbi);
err = get_dnode_of_data(&dn, page->index, LOOKUP_NODE);
@ -1403,19 +1403,18 @@ int do_write_data_page(struct f2fs_io_info *fio)
goto out_writepage;
}
got_it:
err = encrypt_one_page(fio);
if (err)
goto out_writepage;
set_page_writeback(page);
/*
* If current allocation needs SSR,
* it had better in-place writes for updated data.
*/
if (ipu_force || (valid_ipu_blkaddr(fio) && need_inplace_update(fio))) {
err = encrypt_one_page(fio);
if (err)
goto out_writepage;
set_page_writeback(page);
f2fs_put_dnode(&dn);
if (fio->need_lock)
if (fio->need_lock == LOCK_REQ)
f2fs_unlock_op(fio->sbi);
err = rewrite_data_page(fio);
trace_f2fs_do_write_data_page(fio->page, IPU);
@ -1423,6 +1422,20 @@ got_it:
return err;
}
if (fio->need_lock == LOCK_RETRY) {
if (!f2fs_trylock_op(fio->sbi)) {
err = -EAGAIN;
goto out_writepage;
}
fio->need_lock = LOCK_REQ;
}
err = encrypt_one_page(fio);
if (err)
goto out_writepage;
set_page_writeback(page);
/* LFS mode write path */
write_data_page(&dn, fio);
trace_f2fs_do_write_data_page(page, OPU);
@ -1432,7 +1445,7 @@ got_it:
out_writepage:
f2fs_put_dnode(&dn);
out:
if (fio->need_lock)
if (fio->need_lock == LOCK_REQ)
f2fs_unlock_op(fio->sbi);
return err;
}
@ -1458,7 +1471,7 @@ static int __write_data_page(struct page *page, bool *submitted,
.page = page,
.encrypted_page = NULL,
.submitted = false,
.need_lock = true,
.need_lock = LOCK_RETRY,
};
trace_f2fs_writepage(page, DATA);
@ -1494,7 +1507,7 @@ write:
/* Dentry blocks are controlled by checkpoint */
if (S_ISDIR(inode->i_mode)) {
fio.need_lock = false;
fio.need_lock = LOCK_DONE;
err = do_write_data_page(&fio);
goto done;
}
@ -1513,8 +1526,13 @@ write:
goto out;
}
if (err == -EAGAIN)
if (err == -EAGAIN) {
err = do_write_data_page(&fio);
if (err == -EAGAIN) {
fio.need_lock = LOCK_REQ;
err = do_write_data_page(&fio);
}
}
if (F2FS_I(inode)->last_disk_size < psize)
F2FS_I(inode)->last_disk_size = psize;

13
fs/f2fs/f2fs.h
View File

@ -799,6 +799,12 @@ enum temp_type {
NR_TEMP_TYPE,
};
enum need_lock_type {
LOCK_REQ = 0,
LOCK_DONE,
LOCK_RETRY,
};
struct f2fs_io_info {
struct f2fs_sb_info *sbi; /* f2fs_sb_info pointer */
enum page_type type; /* contains DATA/NODE/META/META_FLUSH */
@ -810,7 +816,7 @@ struct f2fs_io_info {
struct page *page; /* page to be written */
struct page *encrypted_page; /* encrypted page */
bool submitted; /* indicate IO submission */
bool need_lock; /* indicate we need to lock cp_rwsem */
int need_lock; /* indicate we need to lock cp_rwsem */
};
#define is_read_io(rw) ((rw) == READ)
@ -1279,6 +1285,11 @@ static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
down_read(&sbi->cp_rwsem);
}
static inline int f2fs_trylock_op(struct f2fs_sb_info *sbi)
{
return down_read_trylock(&sbi->cp_rwsem);
}
static inline void f2fs_unlock_op(struct f2fs_sb_info *sbi)
{
up_read(&sbi->cp_rwsem);

2
fs/f2fs/gc.c
View File

@ -719,7 +719,7 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type,
.old_blkaddr = NULL_ADDR,
.page = page,
.encrypted_page = NULL,
.need_lock = true,
.need_lock = LOCK_REQ,
};
bool is_dirty = PageDirty(page);
int err;

2
fs/f2fs/segment.c
View File

@ -312,7 +312,7 @@ static int __commit_inmem_pages(struct inode *inode,
fio.page = page;
fio.old_blkaddr = NULL_ADDR;
fio.encrypted_page = NULL;
fio.need_lock = false,
fio.need_lock = LOCK_DONE;
err = do_write_data_page(&fio);
if (err) {
unlock_page(page);