Messages in this thread Patch in this message | | | From | Pranay Srivastava <> | Date | Wed, 19 Aug 2020 17:20:59 +0530 | Subject | mountinfo contents changed when rootfs is ramfs |
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Hello,
I'm running a system where rootfs is ramfs. For kernel version 5.2.11
# cat /proc/self/mountinfo 0 0 0:1 / / rw - rootfs rootfs rw %<---snip>%
while for kernel 5.4.58 # cat /proc/self/mountinfo 0 0 0:1 / / rw - rootfs none rw %<---snip>%
The reason for the above difference is because for kernel 5.2.11 the parse_param for rootfs was set to legacy_parse_param which handled the "source" param instead of ignoring it.
With kernel 5.4.58 this is set to ramfs_parse_param which ignores any parameters not recognized and also returns 0 instead of -ENOPARAM. This causes vfs_parse_fs_param to not set the file context source(fc->source) which results in "none" from alloc_vfs_mount(fc->source ? : "none")
The commit which introduced the above change was
commit f32356261d44d580649a7abce1156d15d49cf20f Author: David Howells <dhowells@redhat.com> Date: Mon Mar 25 16:38:31 2019 +0000
vfs: Convert ramfs, shmem, tmpfs, devtmpfs, rootfs to use the new mount API
I'm not sure if this is a regression? But if it is, do we handle it like
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c index ee179a81b3da..47a39baa0535 100644 --- a/fs/ramfs/inode.c +++ b/fs/ramfs/inode.c
@@ -200,7 +200,7 @@ static int ramfs_parse_param(struct fs_context *fc, struct fs_parameter *param) * and as it is used as a !CONFIG_SHMEM simple substitute * for tmpfs, better continue to ignore other mount options. */ - if (opt == -ENOPARAM) + if (opt == -ENOPARAM && strcmp(param->key, "source")) opt = 0; return opt; } so that mountinfo gives the same information as for earlier kernels.
Thanks! -- Regards, Pranay Srivastava
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