• Jan Kara's avatar
    vfs: Move waiting for inode writeback from end_writeback() to evict_inode() · 7994e6f7
    Jan Kara authored
    Currently, I_SYNC can never be set when evict_inode() (and thus
    end_writeback()) is called because flusher thread holds inode reference while
    inode is under writeback. As a result inode_sync_wait() in those places
    currently does nothing. However that is going to change and unveils problems
    with calling inode_sync_wait() from end_writeback(). Several filesystems call
    end_writeback() after they have deleted the inode (btrfs, gfs2, ...) and other
    filesystems (ext3, ext4, reiserfs, ...) can deadlock when waiting for I_SYNC
    because they call end_writeback() from within a transaction.
    
    To avoid these issues, we move inode_sync_wait() into evict_inode() before
    calling ->evict_inode(). That way we preserve the current property that
    ->evict_inode() and writeback never run in parallel and all filesystems are
    safe.
    Signed-off-by: default avatarJan Kara <jack@suse.cz>
    Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
    7994e6f7
inode.c 44.6 KB