diff options
| -rw-r--r-- | fs/autofs4/waitq.c | 135 |
1 files changed, 97 insertions, 38 deletions
diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c index 55aac10cf32..cd3b2a67169 100644 --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -215,19 +215,106 @@ autofs4_find_wait(struct autofs_sb_info *sbi, struct qstr *qstr) return wq; } +/* + * Check if we have a valid request. + * Returns + * 1 if the request should continue. + * In this case we can return an autofs_wait_queue entry if one is + * found or NULL to idicate a new wait needs to be created. + * 0 or a negative errno if the request shouldn't continue. + */ +static int validate_request(struct autofs_wait_queue **wait, + struct autofs_sb_info *sbi, + struct qstr *qstr, + struct dentry*dentry, enum autofs_notify notify) +{ + struct autofs_wait_queue *wq; + struct autofs_info *ino; + + /* Wait in progress, continue; */ + wq = autofs4_find_wait(sbi, qstr); + if (wq) { + *wait = wq; + return 1; + } + + *wait = NULL; + + /* If we don't yet have any info this is a new request */ + ino = autofs4_dentry_ino(dentry); + if (!ino) + return 1; + + /* + * If we've been asked to wait on an existing expire (NFY_NONE) + * but there is no wait in the queue ... + */ + if (notify == NFY_NONE) { + /* + * Either we've betean the pending expire to post it's + * wait or it finished while we waited on the mutex. + * So we need to wait till either, the wait appears + * or the expire finishes. + */ + + while (ino->flags & AUTOFS_INF_EXPIRING) { + mutex_unlock(&sbi->wq_mutex); + schedule_timeout_interruptible(HZ/10); + if (mutex_lock_interruptible(&sbi->wq_mutex)) + return -EINTR; + + wq = autofs4_find_wait(sbi, qstr); + if (wq) { + *wait = wq; + return 1; + } + } + + /* + * Not ideal but the status has already gone. Of the two + * cases where we wait on NFY_NONE neither depend on the + * return status of the wait. + */ + return 0; + } + + /* + * If we've been asked to trigger a mount and the request + * completed while we waited on the mutex ... + */ + if (notify == NFY_MOUNT) { + /* + * If the dentry isn't hashed just go ahead and try the + * mount again with a new wait (not much else we can do). + */ + if (!d_unhashed(dentry)) { + /* + * But if the dentry is hashed, that means that we + * got here through the revalidate path. Thus, we + * need to check if the dentry has been mounted + * while we waited on the wq_mutex. If it has, + * simply return success. + */ + if (d_mountpoint(dentry)) + return 0; + } + } + + return 1; +} + int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry, enum autofs_notify notify) { - struct autofs_info *ino; struct autofs_wait_queue *wq; struct qstr qstr; char *name; - int status, type; + int status, ret, type; /* In catatonic mode, we don't wait for nobody */ if (sbi->catatonic) return -ENOENT; - + name = kmalloc(NAME_MAX + 1, GFP_KERNEL); if (!name) return -ENOMEM; @@ -245,43 +332,15 @@ int autofs4_wait(struct autofs_sb_info *sbi, struct dentry *dentry, qstr.name = name; qstr.hash = full_name_hash(name, qstr.len); - if (mutex_lock_interruptible(&sbi->wq_mutex)) { - kfree(qstr.name); + if (mutex_lock_interruptible(&sbi->wq_mutex)) return -EINTR; - } - - wq = autofs4_find_wait(sbi, &qstr); - ino = autofs4_dentry_ino(dentry); - if (!wq && ino && notify == NFY_NONE) { - /* - * Either we've betean the pending expire to post it's - * wait or it finished while we waited on the mutex. - * So we need to wait till either, the wait appears - * or the expire finishes. - */ - while (ino->flags & AUTOFS_INF_EXPIRING) { - mutex_unlock(&sbi->wq_mutex); - schedule_timeout_interruptible(HZ/10); - if (mutex_lock_interruptible(&sbi->wq_mutex)) { - kfree(qstr.name); - return -EINTR; - } - wq = autofs4_find_wait(sbi, &qstr); - if (wq) - break; - } - - /* - * Not ideal but the status has already gone. Of the two - * cases where we wait on NFY_NONE neither depend on the - * return status of the wait. - */ - if (!wq) { - kfree(qstr.name); + ret = validate_request(&wq, sbi, &qstr, dentry, notify); + if (ret <= 0) { + if (ret == 0) mutex_unlock(&sbi->wq_mutex); - return 0; - } + kfree(qstr.name); + return ret; } if (!wq) { @@ -392,9 +451,9 @@ int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_tok } *wql = wq->next; /* Unlink from chain */ - mutex_unlock(&sbi->wq_mutex); kfree(wq->name.name); wq->name.name = NULL; /* Do not wait on this queue */ + mutex_unlock(&sbi->wq_mutex); wq->status = status; |