diff options
| author | Al Viro | 2012-01-10 22:35:38 -0500 |
|---|---|---|
| committer | Al Viro | 2012-01-11 00:20:12 -0500 |
| commit | d668dc56631da067540b2494d2a1f29ff7b5f15a (patch) | |
| tree | 303ad17208838e8b9b1752f9427d55c84555f0f0 /fs/autofs4 | |
| parent | 8753333266be67ff3a984ac1f6566d31c260bee4 (diff) | |
autofs4: deal with autofs4_write/autofs4_write races
Just serialize the actual writing of packets into pipe on
a new mutex, independent from everything else in the locking
hierarchy. As soon as something has started feeding a piece
of packet into the pipe to daemon, we *want* everything else
about to try the same to wait until we are done.
Acked-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/autofs4')
| -rw-r--r-- | fs/autofs4/autofs_i.h | 1 | ||||
| -rw-r--r-- | fs/autofs4/inode.c | 1 | ||||
| -rw-r--r-- | fs/autofs4/waitq.c | 9 |
3 files changed, 7 insertions, 4 deletions
diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h index 5869d4e974a9..d8d8e7ba6a1e 100644 --- a/fs/autofs4/autofs_i.h +++ b/fs/autofs4/autofs_i.h @@ -116,6 +116,7 @@ struct autofs_sb_info { int needs_reghost; struct super_block *sb; struct mutex wq_mutex; + struct mutex pipe_mutex; spinlock_t fs_lock; struct autofs_wait_queue *queues; /* Wait queue pointer */ spinlock_t lookup_lock; diff --git a/fs/autofs4/inode.c b/fs/autofs4/inode.c index 2ba44c79d548..e16980b00b8d 100644 --- a/fs/autofs4/inode.c +++ b/fs/autofs4/inode.c @@ -225,6 +225,7 @@ int autofs4_fill_super(struct super_block *s, void *data, int silent) sbi->min_proto = 0; sbi->max_proto = 0; mutex_init(&sbi->wq_mutex); + mutex_init(&sbi->pipe_mutex); spin_lock_init(&sbi->fs_lock); sbi->queues = NULL; spin_lock_init(&sbi->lookup_lock); diff --git a/fs/autofs4/waitq.c b/fs/autofs4/waitq.c index 9a0256da5d56..9ef5b2914407 100644 --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -56,26 +56,27 @@ void autofs4_catatonic_mode(struct autofs_sb_info *sbi) mutex_unlock(&sbi->wq_mutex); } -static int autofs4_write(struct file *file, const void *addr, int bytes) +static int autofs4_write(struct autofs_sb_info *sbi, + struct file *file, const void *addr, int bytes) { unsigned long sigpipe, flags; mm_segment_t fs; const char *data = (const char *)addr; ssize_t wr = 0; - /** WARNING: this is not safe for writing more than PIPE_BUF bytes! **/ - sigpipe = sigismember(¤t->pending.signal, SIGPIPE); /* Save pointer to user space and point back to kernel space */ fs = get_fs(); set_fs(KERNEL_DS); + mutex_lock(&sbi->pipe_mutex); while (bytes && (wr = file->f_op->write(file,data,bytes,&file->f_pos)) > 0) { data += wr; bytes -= wr; } + mutex_lock(&sbi->pipe_mutex); set_fs(fs); @@ -179,7 +180,7 @@ static void autofs4_notify_daemon(struct autofs_sb_info *sbi, mutex_unlock(&sbi->wq_mutex); - if (autofs4_write(pipe, &pkt, pktsz)) + if (autofs4_write(sbi, pipe, &pkt, pktsz)) autofs4_catatonic_mode(sbi); fput(pipe); } |