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authorMiklos Szeredi <miklos@szeredi.hu>2006-10-17 00:10:06 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-17 08:18:45 -0700
commit9ffbb9162312fd8113037cb3d94f787f06bbfa9a (patch)
treea8194bb542dcda56271b44d7de23f2a72ecac900 /fs/fuse/file.c
parent48d1a7ea6373337985f27dc1c707649469df5827 (diff)
downloadop-kernel-dev-9ffbb9162312fd8113037cb3d94f787f06bbfa9a.zip
op-kernel-dev-9ffbb9162312fd8113037cb3d94f787f06bbfa9a.tar.gz
[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 <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/fuse/file.c')
-rw-r--r--fs/fuse/file.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 1836268..2bb5ace 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);
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