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fuse: fix nlink after unlink 

Anand Avati reports that the following sequence of system calls fail on a fuse
filesystem:


 	create("filename") => 0
 	link("filename", "linkname") => 0
 	unlink("filename") => 0
 	link("linkname", "filename") => -ENOENT ### BUG ###

vfs_link() fails with ENOENT if i_nlink is zero, this is done to prevent
resurrecting already deleted files.

Fuse clears i_nlink on unlink even if there are other links pointing to the
file.

Reported-by: Anand Avati <avati@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
hifive-unleashed-5.1
Miklos Szeredi 2012-03-05 15:48:11 +01:00
parent 192cfd5877
commit ac45d61357
1 changed files with 15 additions and 7 deletions
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22
fs/fuse/dir.c
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@ -644,13 +644,12 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
fuse_put_request(fc, req);
if (!err) {
struct inode *inode = entry->d_inode;
struct fuse_inode *fi = get_fuse_inode(inode);
/*
* Set nlink to zero so the inode can be cleared, if the inode
* does have more links this will be discovered at the next
* lookup/getattr.
*/
clear_nlink(inode);
spin_lock(&fc->lock);
fi->attr_version = ++fc->attr_version;
drop_nlink(inode);
spin_unlock(&fc->lock);
fuse_invalidate_attr(inode);
fuse_invalidate_attr(dir);
fuse_invalidate_entry_cache(entry);
@ -762,8 +761,17 @@ static int fuse_link(struct dentry *entry, struct inode *newdir,
will reflect changes in the backing inode (link count,
etc.)
*/
if (!err || err == -EINTR)
if (!err) {
struct fuse_inode *fi = get_fuse_inode(inode);
spin_lock(&fc->lock);
fi->attr_version = ++fc->attr_version;
inc_nlink(inode);
spin_unlock(&fc->lock);
fuse_invalidate_attr(inode);
} else if (err == -EINTR) {
fuse_invalidate_attr(inode);
}
return err;
}