[PATCH v2 0/3] add support for drop_caches for individual filesystem

[Ye Bin <yebin@huaweicloud.com>]

From: Ye Bin <yebin10@huawei.com>

In order to better analyze the issue of file system uninstallation caused
by kernel module opening files, it is necessary to perform dentry recycling
on a single file system. But now, apart from global dentry recycling, it is
not supported to do dentry recycling on a single file system separately.
This feature has usage scenarios in problem localization scenarios.At the
same time, it also provides users with a slightly fine-grained
pagecache/entry recycling mechanism.
This patchset supports the recycling of pagecache/entry for individual file
systems.

Diff v2 vs v1:
1. Fix possible live lock for shrink_icache_sb().
2. Introduce reclaim_dcache_sb() for reclaim dentry.
3. Fix potential deadlocks as follows:
https://lore.kernel.org/linux-fsdevel/00000000000098f75506153551a1@google.com/
After some consideration, it was decided that this feature would primarily
be used for debugging purposes. Instead of adding a new IOCTL command, the
task_work mechanism was employed to address potential deadlock issues.

Ye Bin (3):
  vfs: introduce reclaim_icache_sb() and reclaim_dcache_sb() helper
  sysctl: add support for drop_caches for individual filesystem
  Documentation: add instructions for using 'drop_fs_caches sysctl'
    sysctl

 Documentation/admin-guide/sysctl/vm.rst |  34 +++++++
 fs/dcache.c                             |  22 ++++
 fs/drop_caches.c                        | 127 ++++++++++++++++++++++++
 fs/inode.c                              |  21 ++++
 fs/internal.h                           |   1 +
 include/linux/dcache.h                  |   1 +
 6 files changed, 206 insertions(+)

-- 
2.34.1