mirror of
https://git.proxmox.com/git/mirror_zfs.git
synced 2024-11-17 10:01:01 +03:00
b00131d43c
The problem here is that prune_icache() tries to evict/delete both the xattr directory inode as well as at least one xattr inode contained in that directory. Here's what happens: 1. File is created. 2. xattr is created for that file (behind the scenes a xattr directory and a file in that xattr directory are created) 3. File is deleted. 4. Both the xattr directory inode and at least one xattr inode from that directory are evicted by prune_icache(); prune_icache() acquires a lock on both inodes before it calls ->evict() on the inodes When the xattr directory inode is evicted zfs_zinactive attempts to delete the xattr files contained in that directory. While enumerating these files zfs_zget() is called to obtain a reference to the xattr file znode - which tries to lock the xattr inode. However that very same xattr inode was already locked by prune_icache() further up the call stack, thus leading to a deadlock. This can be reliably reproduced like this: $ touch test $ attr -s a -V b test $ rm test $ echo 3 > /proc/sys/vm/drop_caches This patch fixes the deadlock by moving the zfs_purgedir() call to zfs_unlinked_drain(). Instead zfs_rmnode() now checks whether the xattr dir is empty and leaves the xattr dir in the unlinked set if it finds any xattrs. To ensure zfs_unlinked_drain() never accesses a stale super block zfsvfs_teardown() has been update to block until the iput taskq has been drained. This avoids a potential race where a file with an xattr directory is removed and the file system is immediately unmounted. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #266 |
||
|---|---|---|
| .. | ||
| avl | ||
| nvpair | ||
| unicode | ||
| zcommon | ||
| zfs | ||
| zpios | ||
| .gitignore | ||
| Makefile.in | ||