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-rw-r--r--fs/dcache.c31
1 files changed, 16 insertions, 15 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 4d9df3c940e6..f3dcc6351a16 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -90,8 +90,8 @@ static struct kmem_cache *dentry_cache __read_mostly;
/**
* read_seqbegin_or_lock - begin a sequence number check or locking block
- * lock: sequence lock
- * seq : sequence number to be checked
+ * @lock: sequence lock
+ * @seq : sequence number to be checked
*
* First try it once optimistically without taking the lock. If that fails,
* take the lock. The sequence number is also used as a marker for deciding
@@ -103,7 +103,7 @@ static inline void read_seqbegin_or_lock(seqlock_t *lock, int *seq)
if (!(*seq & 1)) /* Even */
*seq = read_seqbegin(lock);
else /* Odd */
- write_seqlock(lock);
+ read_seqlock_excl(lock);
}
static inline int need_seqretry(seqlock_t *lock, int seq)
@@ -114,7 +114,7 @@ static inline int need_seqretry(seqlock_t *lock, int seq)
static inline void done_seqretry(seqlock_t *lock, int seq)
{
if (seq & 1)
- write_sequnlock(lock);
+ read_sequnlock_excl(lock);
}
/*
@@ -2673,9 +2673,9 @@ static int prepend(char **buffer, int *buflen, const char *str, int namelen)
/**
* prepend_name - prepend a pathname in front of current buffer pointer
- * buffer: buffer pointer
- * buflen: allocated length of the buffer
- * name: name string and length qstr structure
+ * @buffer: buffer pointer
+ * @buflen: allocated length of the buffer
+ * @name: name string and length qstr structure
*
* With RCU path tracing, it may race with d_move(). Use ACCESS_ONCE() to
* make sure that either the old or the new name pointer and length are
@@ -2713,14 +2713,15 @@ static int prepend_name(char **buffer, int *buflen, struct qstr *name)
* @buffer: pointer to the end of the buffer
* @buflen: pointer to buffer length
*
- * The function tries to write out the pathname without taking any lock other
- * than the RCU read lock to make sure that dentries won't go away. It only
- * checks the sequence number of the global rename_lock as any change in the
- * dentry's d_seq will be preceded by changes in the rename_lock sequence
- * number. If the sequence number had been change, it will restart the whole
- * pathname back-tracing sequence again. It performs a total of 3 trials of
- * lockless back-tracing sequences before falling back to take the
- * rename_lock.
+ * The function will first try to write out the pathname without taking any
+ * lock other than the RCU read lock to make sure that dentries won't go away.
+ * It only checks the sequence number of the global rename_lock as any change
+ * in the dentry's d_seq will be preceded by changes in the rename_lock
+ * sequence number. If the sequence number had been changed, it will restart
+ * the whole pathname back-tracing sequence again by taking the rename_lock.
+ * In this case, there is no need to take the RCU read lock as the recursive
+ * parent pointer references will keep the dentry chain alive as long as no
+ * rename operation is performed.
*/
static int prepend_path(const struct path *path,
const struct path *root,