From 9ffbb9162312fd8113037cb3d94f787f06bbfa9a Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 17 Oct 2006 00:10:06 -0700 Subject: [PATCH] fuse: fix hang on SMP Fuse didn't always call i_size_write() with i_mutex held which caused rare hangs on SMP/32bit. This bug has been present since fuse-2.2, well before being merged into mainline. The simplest solution is to protect i_size_write() with the per-connection spinlock. Using i_mutex for this purpose would require some restructuring of the code and I'm not even sure it's always safe to acquire i_mutex in all places i_size needs to be set. Since most of vmtruncate is already duplicated for other reasons, duplicate the remaining part as well, making all i_size_write() calls internal to fuse. Using i_size_write() was unnecessary in fuse_init_inode(), since this function is only called on a newly created locked inode. Reported by a few people over the years, but special thanks to Dana Henriksen who was persistent enough in helping me debug it. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fuse/file.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'fs/fuse/file.c') diff --git a/fs/fuse/file.c b/fs/fuse/file.c index 183626868eea..2bb5ace3882d 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -481,8 +481,10 @@ static int fuse_commit_write(struct file *file, struct page *page, err = -EIO; if (!err) { pos += count; - if (pos > i_size_read(inode)) + spin_lock(&fc->lock); + if (pos > inode->i_size) i_size_write(inode, pos); + spin_unlock(&fc->lock); if (offset == 0 && to == PAGE_CACHE_SIZE) { clear_page_dirty(page); @@ -586,8 +588,12 @@ static ssize_t fuse_direct_io(struct file *file, const char __user *buf, } fuse_put_request(fc, req); if (res > 0) { - if (write && pos > i_size_read(inode)) - i_size_write(inode, pos); + if (write) { + spin_lock(&fc->lock); + if (pos > inode->i_size) + i_size_write(inode, pos); + spin_unlock(&fc->lock); + } *ppos = pos; } fuse_invalidate_attr(inode); -- cgit v1.2.1