Editing Inode (section)

===Simplified library installation with inode file systems===

inode file systems allow a running process to continue accessing a library file even as another process is replacing that same file.

This operation should be performed [[Atomicity (programming)|atomically]], meaning it should appear as a single operation that is either entirely completed or not done at all, with no intermediate state visible to other processes.

During the [[Read–modify–write|replacement]], a new inode is created for the new [[Library (computing)|library file]], establishing an entirely new mapping. Subsequently, future access requests for that library will retrieve the newly installed version.

When the operating system is replacing the file (and creating a new inode), it places a lock<ref>{{cite web | url = https://www.kernel.org/doc/html/latest/filesystems/locking.html | title=Locking | author=The kernel development community | access-date=21 May 2023 | website=kernel.org }}</ref> on the inode<ref>{{cite web | url = https://www.kernel.org/doc/html/latest/filesystems/vfs.html#struct-inode-operations | title=struct inode_operations | author=Gooch, Richard | editor=Enberg, Pekka | access-date=21 May 2023 | website=kernel.org }}</ref> and possibly the containing directory.<ref>{{cite web | url = https://www.kernel.org/doc/html/latest/filesystems/directory-locking.html | title=Directory Locking | author=The kernel development community | access-date=21 May 2023 | website=kernel.org }}</ref> This prevents other processes from [[Readers–writer lock|reading or writing]] to the file (inode)<ref>{{cite web | url = https://www.kernel.org/doc/html/latest/locking/locktypes.html | title=Lock types and their rules | author=The kernel development community | access-date=21 May 2023 | website=kernel.org }}</ref> during the update operation, thereby avoiding data inconsistency or corruption.<ref>{{cite web | url = https://www.kernel.org/doc/html/latest/locking/lockdep-design.html | title=Runtime locking correctness validator | author-first=Molnar, I. | author-last=van de Ven, A. | access-date=21 May 2023 | website=kernel.org }}</ref>

Once the update operation is complete, the lock is released. Any subsequent access to the file (via the inode) by any processes will now point to the new version of the library. Thus, making it possible to perform updates even when the library is in use by another process.

One significant advantage of this mechanism is that it eliminates the need for a [[Booting|system reboot]] to replace libraries currently in use. Consequently, systems can update or upgrade [[software libraries]] seamlessly without interrupting running processes or operations.