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* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (33 commits) ext4: Regularize mount options ext4: fix locking typo in mballoc which could cause soft lockup hangs ext4: fix typo which causes a memory leak on error path jbd2: Update locking coments ext4: Rename pa_linear to pa_type ext4: add checks of block references for non-extent inodes ext4: Check for an valid i_mode when reading the inode from disk ext4: Use WRITE_SYNC for commits which are caused by fsync() ext4: Add auto_da_alloc mount option ext4: Use struct flex_groups to calculate get_orlov_stats() ext4: Use atomic_t's in struct flex_groups ext4: remove /proc tuning knobs ext4: Add sysfs support ext4: Track lifetime disk writes ext4: Fix discard of inode prealloc space with delayed allocation. ext4: Automatically allocate delay allocated blocks on rename ext4: Automatically allocate delay allocated blocks on close ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl ext4: Simplify delalloc code by removing mpage_da_writepages() ext4: Save stack space by removing fake buffer heads ... |
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This directory attempts to document the ABI between the Linux kernel and userspace, and the relative stability of these interfaces. Due to the everchanging nature of Linux, and the differing maturity levels, these interfaces should be used by userspace programs in different ways. We have four different levels of ABI stability, as shown by the four different subdirectories in this location. Interfaces may change levels of stability according to the rules described below. The different levels of stability are: stable/ This directory documents the interfaces that the developer has defined to be stable. Userspace programs are free to use these interfaces with no restrictions, and backward compatibility for them will be guaranteed for at least 2 years. Most interfaces (like syscalls) are expected to never change and always be available. testing/ This directory documents interfaces that are felt to be stable, as the main development of this interface has been completed. The interface can be changed to add new features, but the current interface will not break by doing this, unless grave errors or security problems are found in them. Userspace programs can start to rely on these interfaces, but they must be aware of changes that can occur before these interfaces move to be marked stable. Programs that use these interfaces are strongly encouraged to add their name to the description of these interfaces, so that the kernel developers can easily notify them if any changes occur (see the description of the layout of the files below for details on how to do this.) obsolete/ This directory documents interfaces that are still remaining in the kernel, but are marked to be removed at some later point in time. The description of the interface will document the reason why it is obsolete and when it can be expected to be removed. The file Documentation/feature-removal-schedule.txt may describe some of these interfaces, giving a schedule for when they will be removed. removed/ This directory contains a list of the old interfaces that have been removed from the kernel. Every file in these directories will contain the following information: What: Short description of the interface Date: Date created KernelVersion: Kernel version this feature first showed up in. Contact: Primary contact for this interface (may be a mailing list) Description: Long description of the interface and how to use it. Users: All users of this interface who wish to be notified when it changes. This is very important for interfaces in the "testing" stage, so that kernel developers can work with userspace developers to ensure that things do not break in ways that are unacceptable. It is also important to get feedback for these interfaces to make sure they are working in a proper way and do not need to be changed further. How things move between levels: Interfaces in stable may move to obsolete, as long as the proper notification is given. Interfaces may be removed from obsolete and the kernel as long as the documented amount of time has gone by. Interfaces in the testing state can move to the stable state when the developers feel they are finished. They cannot be removed from the kernel tree without going through the obsolete state first. It's up to the developer to place their interfaces in the category they wish for it to start out in.