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authorTristan Ye <tristan.ye@oracle.com>2010-12-07 06:35:07 (GMT)
committerJoel Becker <joel.becker@oracle.com>2010-12-09 23:36:48 (GMT)
commit39c99f12f15c8bf8257985d9b2a2548a03d18c00 (patch)
tree38f09ce41f6cbfd3a73b1dc66098ba3bf05e2d6a
parent388c4bcb4e63e88fb1f312a2f5f9eb2623afcf5b (diff)
downloadlinux-fsl-qoriq-39c99f12f15c8bf8257985d9b2a2548a03d18c00.tar.xz
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 <tristan.ye@oracle.com> Signed-off-by: Joel Becker <joel.becker@oracle.com>
-rw-r--r--fs/ocfs2/aops.c7
-rw-r--r--fs/ocfs2/aops.h23
-rw-r--r--fs/ocfs2/file.c15
3 files changed, 39 insertions, 6 deletions
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index f1e962c..0d7c554 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 76bfdfd..eceb456 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 77b4c04..f6cba56 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);