kernel/linux.git/include/linux/kernfs.h, branch linux-4.20.y

kernfs: update comment about kernfs_path() return value

2018-09-16T20:37:16+00:00

Now it returns the length of the full path or error code. Signed-off-by: Konstantin Khlebnikov Fixes: 3abb1d90f5d9 ("kernfs: make kernfs_path*() behave in the style of strlcpy()") Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

kernfs: allow creating kernfs objects with arbitrary uid/gid

2018-07-21T06:44:35+00:00

This change allows creating kernfs files and directories with arbitrary uid/gid instead of always using GLOBAL_ROOT_UID/GID by extending kernfs_create_dir_ns() and kernfs_create_file_ns() with uid/gid arguments. The "simple" kernfs_create_file() and kernfs_create_dir() are left alone and always create objects belonging to the global root. When creating symlinks ownership (uid/gid) is taken from the target kernfs object. Co-Developed-by: Tyler Hicks Signed-off-by: Dmitry Torokhov Signed-off-by: Tyler Hicks Signed-off-by: David S. Miller

blktrace: add an option to allow displaying cgroup path

2017-07-29T15:00:03+00:00

By default we output cgroup id in blktrace. This adds an option to display cgroup path. Since get cgroup path is a relativly heavy operation, we don't enable it by default. with the option enabled, blktrace will output something like this: dd-1353 [007] d..2 293.015252: 8,0 /test/level D R 24 + 8 [dd] Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

kernfs: add exportfs operations

2017-07-29T15:00:03+00:00

Now we have the facilities to implement exportfs operations. The idea is cgroup can export the fhandle info to userspace, then userspace uses fhandle to find the cgroup name. Another example is userspace can get fhandle for a cgroup and BPF uses the fhandle to filter info for the cgroup. Acked-by: Greg Kroah-Hartman Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

kernfs: introduce kernfs_node_id

2017-07-29T15:00:03+00:00

inode number and generation can identify a kernfs node. We are going to export the identification by exportfs operations, so put ino and generation into a separate structure. It's convenient when later patches use the identification. Acked-by: Greg Kroah-Hartman Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

kernfs: implement i_generation

2017-07-29T15:00:03+00:00

Set i_generation for kernfs inode. This is required to implement exportfs operations. The generation is 32-bit, so it's possible the generation wraps up and we find stale files. To reduce the posssibility, we don't reuse inode numer immediately. When the inode number allocation wraps, we increase generation number. In this way generation/inode number consist of a 64-bit number which is unlikely duplicated. This does make the idr tree more sparse and waste some memory. Since idr manages 32-bit keys, idr uses a 6-level radix tree, each level covers 6 bits of the key. In a 100k inode kernfs, the worst case will have around 300k radix tree node. Each node is 576bytes, so the tree will use about ~150M memory. Sounds not too bad, if this really is a problem, we should find better data structure. Acked-by: Tejun Heo Acked-by: Greg Kroah-Hartman Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

kernfs: use idr instead of ida to manage inode number

2017-07-29T15:00:03+00:00

kernfs uses ida to manage inode number. The problem is we can't get kernfs_node from inode number with ida. Switching to use idr, next patch will add an API to get kernfs_node from inode number. Acked-by: Tejun Heo Acked-by: Greg Kroah-Hartman Signed-off-by: Shaohua Li Signed-off-by: Jens Axboe

kernfs: add kernfs_ops->open/release() callbacks

2016-12-27T19:49:03+00:00

Add ->open/release() methods to kernfs_ops. ->open() is called when the file is opened and ->release() when the file is either released or severed. These callbacks can be used, for example, to manage persistent caching objects over multiple seq_file iterations. Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Acked-by: Acked-by: Zefan Li

kernfs: make kernfs_open_file->mmapped a bitfield

2016-12-27T19:49:02+00:00

More kernfs_open_file->mutex synchronized flags are planned to be added. Convert ->mmapped to a bitfield in preparation. While at it, make kernfs_fop_mmap() use "true" instead of "1" on ->mmapped. Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Acked-by: Acked-by: Zefan Li

kernfs: remove kernfs_path_len()

2016-08-10T15:23:44+00:00

It doesn't have any in-kernel user and the same result can be obtained from kernfs_path(@kn, NULL, 0). Remove it. Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Cc: Serge Hallyn