From cc15620bc826b14006956fd321e026ae96aff53a Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 12 May 2017 13:51:34 -0700 Subject: [PATCH] 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 Signed-off-by: Jaegeuk Kim --- fs/f2fs/data.c | 44 +++++++++++++++++++++++++++++++------------- fs/f2fs/f2fs.h | 13 ++++++++++++- fs/f2fs/gc.c | 2 +- fs/f2fs/segment.c | 2 +- 4 files changed, 45 insertions(+), 16 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 4ca0899621a0..779a306858a2 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -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; diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index c6643783adff..f61e095947c8 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -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); diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c index e2b13558a915..14c71ac76062 100644 --- a/fs/f2fs/gc.c +++ b/fs/f2fs/gc.c @@ -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; diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index fcada9d03817..3bc36769ec9f 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -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);