Module Name: src Committed By: manu Date: Sat Nov 15 05:03:55 UTC 2014
Modified Files: src/sys/ufs/ufs: ufs_extattr.c Log Message: Fix UFS1 extended attribute backend autocreation deadlock UFS1 extended attribute backend autocration goes through a vn_open() to create the backend file, and this forces us to release the lock on the target node, in case the target is within the parents of the backend file. That created a window within which another thread could acquire a lock on the target vnode and deadlock awaiting for the mount extended attribute lock. We fix the problem by also releasing the mount extended attribute lock when calling vn_open(), but that lets another thread race us for backend creation. We just detect this using O_EXCL for vn_open() and by checking for EEXIST return code. If we are raced, we fail backend creation but this is not a problem since another thread succeeded on it: we just have to use the result. To generate a diff of this commit: cvs rdiff -u -r1.44 -r1.45 src/sys/ufs/ufs/ufs_extattr.c Please note that diffs are not public domain; they are subject to the copyright notices on the relevant files.