| Message ID | 20210928060633.349231-1-vshankar@redhat.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | ceph: add debugfs entries signifying new mount syntax support | expand |
On Tue, 2021-09-28 at 11:36 +0530, Venky Shankar wrote: > v3: > - create mount syntax debugfs entries under /<>/ceph/meta/client_features directory > - mount syntax debugfs file names are v1, v2,... (were v1_mount_sytnax,... earlier) > > [This is based on top of new mount syntax series] > > Patrick proposed the idea of having debugfs entries to signify if > kernel supports the new (v2) mount syntax. The primary use of this > information is to catch any bugs in the new syntax implementation. > > This would be done as follows:: > > The userspace mount helper tries to mount using the new mount syntax > and fallsback to using old syntax if the mount using new syntax fails. > However, a bug in the new mount syntax implementation can silently > result in the mount helper switching to old syntax. > > So, the debugfs entries can be relied upon by the mount helper to > check if the kernel supports the new mount syntax. Cases when the > mount using the new syntax fails, but the kernel does support the > new mount syntax, the mount helper could probably log before switching > to the old syntax (or fail the mount altogether when run in test mode). > > Debugfs entries are as follows:: > > /sys/kernel/debug/ceph/ > .... > .... > /sys/kernel/debug/ceph/meta > /sys/kernel/debug/ceph/meta/client_features > /sys/kernel/debug/ceph/meta/client_features/v2 > /sys/kernel/debug/ceph/meta/client_features/v1 > .... > .... > The patches look fine, technically, so I think we're down to the bikeshedding here. My minor gripe is that "v1" and "v2" are not really client features. Perhaps we should call these "mount_format_v1" or maybe "mount_syntax_v1" ? I could forsee is advertising other features in this dir in the future, and at that point "v1" and "v2" are somewhat ambiguous for names. Make sense? > Venky Shankar (2): > libceph: export ceph_debugfs_dir for use in ceph.ko > ceph: add debugfs entries for mount syntax support > > fs/ceph/debugfs.c | 41 ++++++++++++++++++++++++++++++++++++ > fs/ceph/super.c | 3 +++ > fs/ceph/super.h | 2 ++ > include/linux/ceph/debugfs.h | 2 ++ > net/ceph/debugfs.c | 3 ++- > 5 files changed, 50 insertions(+), 1 deletion(-) >
On Thu, Sep 30, 2021 at 4:58 PM Jeff Layton <jlayton@redhat.com> wrote: > > On Tue, 2021-09-28 at 11:36 +0530, Venky Shankar wrote: > > v3: > > - create mount syntax debugfs entries under /<>/ceph/meta/client_features directory > > - mount syntax debugfs file names are v1, v2,... (were v1_mount_sytnax,... earlier) > > > > [This is based on top of new mount syntax series] > > > > Patrick proposed the idea of having debugfs entries to signify if > > kernel supports the new (v2) mount syntax. The primary use of this > > information is to catch any bugs in the new syntax implementation. > > > > This would be done as follows:: > > > > The userspace mount helper tries to mount using the new mount syntax > > and fallsback to using old syntax if the mount using new syntax fails. > > However, a bug in the new mount syntax implementation can silently > > result in the mount helper switching to old syntax. > > > > So, the debugfs entries can be relied upon by the mount helper to > > check if the kernel supports the new mount syntax. Cases when the > > mount using the new syntax fails, but the kernel does support the > > new mount syntax, the mount helper could probably log before switching > > to the old syntax (or fail the mount altogether when run in test mode). > > > > Debugfs entries are as follows:: > > > > /sys/kernel/debug/ceph/ > > .... > > .... > > /sys/kernel/debug/ceph/meta > > /sys/kernel/debug/ceph/meta/client_features > > /sys/kernel/debug/ceph/meta/client_features/v2 > > /sys/kernel/debug/ceph/meta/client_features/v1 > > .... > > .... > > > > The patches look fine, technically, so I think we're down to the > bikeshedding here. > > My minor gripe is that "v1" and "v2" are not really client features. > Perhaps we should call these "mount_format_v1" or maybe > "mount_syntax_v1" ? I could forsee is advertising other features in this > dir in the future, and at that point "v1" and "v2" are somewhat > ambiguous for names. > > Make sense? Doh! I changed this from "v1_mount_syntax" to just "v1" ;P Let's call it mount_syntax_v1,.. > > > > Venky Shankar (2): > > libceph: export ceph_debugfs_dir for use in ceph.ko > > ceph: add debugfs entries for mount syntax support > > > > fs/ceph/debugfs.c | 41 ++++++++++++++++++++++++++++++++++++ > > fs/ceph/super.c | 3 +++ > > fs/ceph/super.h | 2 ++ > > include/linux/ceph/debugfs.h | 2 ++ > > net/ceph/debugfs.c | 3 ++- > > 5 files changed, 50 insertions(+), 1 deletion(-) > > > > -- > Jeff Layton <jlayton@redhat.com> >
v3: - create mount syntax debugfs entries under /<>/ceph/meta/client_features directory - mount syntax debugfs file names are v1, v2,... (were v1_mount_sytnax,... earlier) [This is based on top of new mount syntax series] Patrick proposed the idea of having debugfs entries to signify if kernel supports the new (v2) mount syntax. The primary use of this information is to catch any bugs in the new syntax implementation. This would be done as follows:: The userspace mount helper tries to mount using the new mount syntax and fallsback to using old syntax if the mount using new syntax fails. However, a bug in the new mount syntax implementation can silently result in the mount helper switching to old syntax. So, the debugfs entries can be relied upon by the mount helper to check if the kernel supports the new mount syntax. Cases when the mount using the new syntax fails, but the kernel does support the new mount syntax, the mount helper could probably log before switching to the old syntax (or fail the mount altogether when run in test mode). Debugfs entries are as follows:: /sys/kernel/debug/ceph/ .... .... /sys/kernel/debug/ceph/meta /sys/kernel/debug/ceph/meta/client_features /sys/kernel/debug/ceph/meta/client_features/v2 /sys/kernel/debug/ceph/meta/client_features/v1 .... .... Venky Shankar (2): libceph: export ceph_debugfs_dir for use in ceph.ko ceph: add debugfs entries for mount syntax support fs/ceph/debugfs.c | 41 ++++++++++++++++++++++++++++++++++++ fs/ceph/super.c | 3 +++ fs/ceph/super.h | 2 ++ include/linux/ceph/debugfs.h | 2 ++ net/ceph/debugfs.c | 3 ++- 5 files changed, 50 insertions(+), 1 deletion(-)