From 39c99f12f15c8bf8257985d9b2a2548a03d18c00 Mon Sep 17 00:00:00 2001 From: Tristan Ye Date: Tue, 7 Dec 2010 14:35:07 +0800 Subject: [PATCH] Ocfs2: Teach 'coherency=full' O_DIRECT writes to correctly up_read i_alloc_sem. Due to newly-introduced 'coherency=full' O_DIRECT writes also takes the EX rw_lock like buffered writes did(rw_level == 1), it turns out messing the usage of 'level' in ocfs2_dio_end_io() up, which caused i_alloc_sem being failed to get up_read'd correctly. This patch tries to teach ocfs2_dio_end_io to understand well on all locking stuffs by explicitly introducing a new bit for i_alloc_sem in iocb's private data, just like what we did for rw_lock. Signed-off-by: Tristan Ye Signed-off-by: Joel Becker --- fs/ocfs2/aops.c | 7 +++++-- fs/ocfs2/aops.h | 23 +++++++++++++++++++++-- fs/ocfs2/file.c | 15 +++++++++++++-- 3 files changed, 39 insertions(+), 6 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index f1e962cb3b73..0d7c5540ad66 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -573,11 +573,14 @@ static void ocfs2_dio_end_io(struct kiocb *iocb, /* this io's submitter should not have unlocked this before we could */ BUG_ON(!ocfs2_iocb_is_rw_locked(iocb)); + if (ocfs2_iocb_is_sem_locked(iocb)) { + up_read(&inode->i_alloc_sem); + ocfs2_iocb_clear_sem_locked(iocb); + } + ocfs2_iocb_clear_rw_locked(iocb); level = ocfs2_iocb_rw_locked_level(iocb); - if (!level) - up_read(&inode->i_alloc_sem); ocfs2_rw_unlock(inode, level); if (is_async) diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h index 76bfdfda691a..eceb456037c1 100644 --- a/fs/ocfs2/aops.h +++ b/fs/ocfs2/aops.h @@ -68,8 +68,27 @@ static inline void ocfs2_iocb_set_rw_locked(struct kiocb *iocb, int level) else clear_bit(1, (unsigned long *)&iocb->private); } + +/* + * Using a named enum representing lock types in terms of #N bit stored in + * iocb->private, which is going to be used for communication bewteen + * ocfs2_dio_end_io() and ocfs2_file_aio_write/read(). + */ +enum ocfs2_iocb_lock_bits { + OCFS2_IOCB_RW_LOCK = 0, + OCFS2_IOCB_RW_LOCK_LEVEL, + OCFS2_IOCB_SEM, + OCFS2_IOCB_NUM_LOCKS +}; + #define ocfs2_iocb_clear_rw_locked(iocb) \ - clear_bit(0, (unsigned long *)&iocb->private) + clear_bit(OCFS2_IOCB_RW_LOCK, (unsigned long *)&iocb->private) #define ocfs2_iocb_rw_locked_level(iocb) \ - test_bit(1, (unsigned long *)&iocb->private) + test_bit(OCFS2_IOCB_RW_LOCK_LEVEL, (unsigned long *)&iocb->private) +#define ocfs2_iocb_set_sem_locked(iocb) \ + set_bit(OCFS2_IOCB_SEM, (unsigned long *)&iocb->private) +#define ocfs2_iocb_clear_sem_locked(iocb) \ + clear_bit(OCFS2_IOCB_SEM, (unsigned long *)&iocb->private) +#define ocfs2_iocb_is_sem_locked(iocb) \ + test_bit(OCFS2_IOCB_SEM, (unsigned long *)&iocb->private) #endif /* OCFS2_FILE_H */ diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 77b4c04a2809..f6cba566429d 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2241,11 +2241,15 @@ static ssize_t ocfs2_file_aio_write(struct kiocb *iocb, mutex_lock(&inode->i_mutex); + ocfs2_iocb_clear_sem_locked(iocb); + relock: /* to match setattr's i_mutex -> i_alloc_sem -> rw_lock ordering */ if (direct_io) { down_read(&inode->i_alloc_sem); have_alloc_sem = 1; + /* communicate with ocfs2_dio_end_io */ + ocfs2_iocb_set_sem_locked(iocb); } /* @@ -2382,8 +2386,10 @@ out: ocfs2_rw_unlock(inode, rw_level); out_sems: - if (have_alloc_sem) + if (have_alloc_sem) { up_read(&inode->i_alloc_sem); + ocfs2_iocb_clear_sem_locked(iocb); + } mutex_unlock(&inode->i_mutex); @@ -2527,6 +2533,8 @@ static ssize_t ocfs2_file_aio_read(struct kiocb *iocb, goto bail; } + ocfs2_iocb_clear_sem_locked(iocb); + /* * buffered reads protect themselves in ->readpage(). O_DIRECT reads * need locks to protect pending reads from racing with truncate. @@ -2534,6 +2542,7 @@ static ssize_t ocfs2_file_aio_read(struct kiocb *iocb, if (filp->f_flags & O_DIRECT) { down_read(&inode->i_alloc_sem); have_alloc_sem = 1; + ocfs2_iocb_set_sem_locked(iocb); ret = ocfs2_rw_lock(inode, 0); if (ret < 0) { @@ -2575,8 +2584,10 @@ static ssize_t ocfs2_file_aio_read(struct kiocb *iocb, } bail: - if (have_alloc_sem) + if (have_alloc_sem) { up_read(&inode->i_alloc_sem); + ocfs2_iocb_clear_sem_locked(iocb); + } if (rw_level != -1) ocfs2_rw_unlock(inode, rw_level); mlog_exit(ret);