Name spaces represented as a lookup table acquire read

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Unformatted text preview: ciples of Data Management Spring 2013 GFS does not have a per-directory structure that lists files in the directory CS480 Principles of Data Management Spring 2013 Each master operation acquires a set of locks before it runs •  If opera4on involves /d1/d2/…/dn/leaf! •  Name spaces represented as a lookup table –  Acquire read locks on directory names –  Maps full pathnames to metadata •  /d1, /d1/d2, …, /d1/d2/…/dn! –  Read or write lock on full pathname •  File crea4on does not require a lock on the directory structure •  /d1/d2/…/dn/leaf! •  Used to prevent opera4ons during snapshots –  No inode needs to be protected from modifica4on –  For e.g. cannot create /home/user/foo! –  While /home/user is being snapsho_ed to /save/user ! 7 Colorado State University, Sangmi Pallickara 2/14/13 CS480 Principles of Data Management Spring 2013 Locks are used to prevent operations during snapshots Colorado State University, Sangmi Pallickara 2/14/13 CS480 Principles of Data Management 8 Spring 2013 •  For e.g. cannot create /home/user/foo! –  While /home/user is being snapsho_ed to /save/user ! Deletion of Files & " Garbage Collection •  Read locks on /home and /save •  Write lock on /home/user and /save/user •  File crea4on does not require write lock on parent directory...
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This note was uploaded on 02/11/2014 for the course CS 480 taught by Professor Staff during the Spring '08 term at Colorado State.

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