From c18ceab01240fd4c354b78d877571b729908e4a3 Mon Sep 17 00:00:00 2001 From: Wengang Wang Date: Thu, 3 Apr 2014 14:46:46 -0700 Subject: [PATCH] ocfs2: change ip_unaligned_aio to of type mutex from atomit_t There is a problem that waitqueue_active() may check stale data thus miss a wakeup of threads waiting on ip_unaligned_aio. The valid value of ip_unaligned_aio is only 0 and 1 so we can change it to be of type mutex thus the above prolem is avoid. Another benifit is that mutex which works as FIFO is fairer than wake_up_all(). Signed-off-by: Wengang Wang Cc: Mark Fasheh Cc: Joel Becker Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/aops.c | 6 +----- fs/ocfs2/aops.h | 5 ----- fs/ocfs2/file.c | 15 +++------------ fs/ocfs2/inode.h | 2 +- fs/ocfs2/super.c | 9 ++------- 5 files changed, 7 insertions(+), 30 deletions(-) diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index aeb44e879c51..ebe44f7dce0b 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -571,7 +571,6 @@ static void ocfs2_dio_end_io(struct kiocb *iocb, { struct inode *inode = file_inode(iocb->ki_filp); int level; - wait_queue_head_t *wq = ocfs2_ioend_wq(inode); /* this io's submitter should not have unlocked this before we could */ BUG_ON(!ocfs2_iocb_is_rw_locked(iocb)); @@ -582,10 +581,7 @@ static void ocfs2_dio_end_io(struct kiocb *iocb, if (ocfs2_iocb_is_unaligned_aio(iocb)) { ocfs2_iocb_clear_unaligned_aio(iocb); - if (atomic_dec_and_test(&OCFS2_I(inode)->ip_unaligned_aio) && - waitqueue_active(wq)) { - wake_up_all(wq); - } + mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio); } ocfs2_iocb_clear_rw_locked(iocb); diff --git a/fs/ocfs2/aops.h b/fs/ocfs2/aops.h index f671e49beb34..6cae155d54df 100644 --- a/fs/ocfs2/aops.h +++ b/fs/ocfs2/aops.h @@ -102,9 +102,4 @@ enum ocfs2_iocb_lock_bits { #define ocfs2_iocb_is_unaligned_aio(iocb) \ test_bit(OCFS2_IOCB_UNALIGNED_IO, (unsigned long *)&iocb->private) -#define OCFS2_IOEND_WQ_HASH_SZ 37 -#define ocfs2_ioend_wq(v) (&ocfs2__ioend_wq[((unsigned long)(v)) %\ - OCFS2_IOEND_WQ_HASH_SZ]) -extern wait_queue_head_t ocfs2__ioend_wq[OCFS2_IOEND_WQ_HASH_SZ]; - #endif /* OCFS2_FILE_H */ diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index 51632c40e896..1673438789fe 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2061,13 +2061,6 @@ out: return ret; } -static void ocfs2_aiodio_wait(struct inode *inode) -{ - wait_queue_head_t *wq = ocfs2_ioend_wq(inode); - - wait_event(*wq, (atomic_read(&OCFS2_I(inode)->ip_unaligned_aio) == 0)); -} - static int ocfs2_is_io_unaligned(struct inode *inode, size_t count, loff_t pos) { int blockmask = inode->i_sb->s_blocksize - 1; @@ -2345,10 +2338,8 @@ relock: * Wait on previous unaligned aio to complete before * proceeding. */ - ocfs2_aiodio_wait(inode); - - /* Mark the iocb as needing a decrement in ocfs2_dio_end_io */ - atomic_inc(&OCFS2_I(inode)->ip_unaligned_aio); + mutex_lock(&OCFS2_I(inode)->ip_unaligned_aio); + /* Mark the iocb as needing an unlock in ocfs2_dio_end_io */ ocfs2_iocb_set_unaligned_aio(iocb); } @@ -2428,7 +2419,7 @@ out_dio: if (unaligned_dio) { ocfs2_iocb_clear_unaligned_aio(iocb); - atomic_dec(&OCFS2_I(inode)->ip_unaligned_aio); + mutex_unlock(&OCFS2_I(inode)->ip_unaligned_aio); } out: diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h index 621fc73bf23d..9f1580b506a5 100644 --- a/fs/ocfs2/inode.h +++ b/fs/ocfs2/inode.h @@ -44,7 +44,7 @@ struct ocfs2_inode_info struct rw_semaphore ip_xattr_sem; /* Number of outstanding AIO's which are not page aligned */ - atomic_t ip_unaligned_aio; + struct mutex ip_unaligned_aio; /* These fields are protected by ip_lock */ spinlock_t ip_lock; diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c index 49d84f80f36c..d17145552097 100644 --- a/fs/ocfs2/super.c +++ b/fs/ocfs2/super.c @@ -1612,14 +1612,9 @@ static int ocfs2_show_options(struct seq_file *s, struct dentry *root) return 0; } -wait_queue_head_t ocfs2__ioend_wq[OCFS2_IOEND_WQ_HASH_SZ]; - static int __init ocfs2_init(void) { - int status, i; - - for (i = 0; i < OCFS2_IOEND_WQ_HASH_SZ; i++) - init_waitqueue_head(&ocfs2__ioend_wq[i]); + int status; status = init_ocfs2_uptodate_cache(); if (status < 0) @@ -1761,7 +1756,7 @@ static void ocfs2_inode_init_once(void *data) ocfs2_extent_map_init(&oi->vfs_inode); INIT_LIST_HEAD(&oi->ip_io_markers); oi->ip_dir_start_lookup = 0; - atomic_set(&oi->ip_unaligned_aio, 0); + mutex_init(&oi->ip_unaligned_aio); init_rwsem(&oi->ip_alloc_sem); init_rwsem(&oi->ip_xattr_sem); mutex_init(&oi->ip_io_mutex); -- 2.20.1