github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-24 15:12:13 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

kernfs: add warning about implementing freeze/thaw

Browse Source 
Sysfs is built on top of kernfs and sysfs provides the power management
infrastructure to support suspend/hibernate by writing to various files
in /sys/power/. As filesystems may be automatically frozen during
suspend/hibernate implementing freeze/thaw support for kernfs
generically will cause deadlocks as the suspending/hibernation
initiating task will hold a VFS lock that it will then wait upon to be
released. If freeze/thaw for kernfs is needed talk to the VFS.

Link: https://lore.kernel.org/r/20250402-work-freeze-v2-4-6719a97b52ac@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2025-04-02 16:07:34 +02:00
parent eacfbf7419
commit ef2ed04eba
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
fs/kernfs/mount.c
View File

@ -62,6 +62,21 @@ const struct super_operations kernfs_sops = {
.show_options = kernfs_sop_show_options,
.show_path = kernfs_sop_show_path,
/*
* sysfs is built on top of kernfs and sysfs provides the power
* management infrastructure to support suspend/hibernate by
* writing to various files in /sys/power/. As filesystems may
* be automatically frozen during suspend/hibernate implementing
* freeze/thaw support for kernfs generically will cause
* deadlocks as the suspending/hibernation initiating task will
* hold a VFS lock that it will then wait upon to be released.
* If freeze/thaw for kernfs is needed talk to the VFS.
*/
.freeze_fs = NULL,
.unfreeze_fs = NULL,
.freeze_super = NULL,
.thaw_super = NULL,
};
static int kernfs_encode_fh(struct inode *inode, __u32 *fh, int *max_len,