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/dir.c | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) (limited to 'fs/fuse/dir.c') diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index 8605155db171..a8f65c11aa2c 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -935,14 +935,30 @@ static void iattr_to_fattr(struct iattr *iattr, struct fuse_setattr_in *arg) } } +static void fuse_vmtruncate(struct inode *inode, loff_t offset) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + int need_trunc; + + spin_lock(&fc->lock); + need_trunc = inode->i_size > offset; + i_size_write(inode, offset); + spin_unlock(&fc->lock); + + if (need_trunc) { + struct address_space *mapping = inode->i_mapping; + unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); + truncate_inode_pages(mapping, offset); + } +} + /* * Set attributes, and at the same time refresh them. * * Truncation is slightly complicated, because the 'truncate' request * may fail, in which case we don't want to touch the mapping. - * vmtruncate() doesn't allow for this case. So do the rlimit - * checking by hand and call vmtruncate() only after the file has - * actually been truncated. + * vmtruncate() doesn't allow for this case, so do the rlimit checking + * and the actual truncation by hand. */ static int fuse_setattr(struct dentry *entry, struct iattr *attr) { @@ -993,12 +1009,8 @@ static int fuse_setattr(struct dentry *entry, struct iattr *attr) make_bad_inode(inode); err = -EIO; } else { - if (is_truncate) { - loff_t origsize = i_size_read(inode); - i_size_write(inode, outarg.attr.size); - if (origsize > outarg.attr.size) - vmtruncate(inode, outarg.attr.size); - } + if (is_truncate) + fuse_vmtruncate(inode, outarg.attr.size); fuse_change_attributes(inode, &outarg.attr); fi->i_time = time_to_jiffies(outarg.attr_valid, outarg.attr_valid_nsec); -- cgit v1.2.3