| Message ID | 4E5807A8.2020600@netapp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Aug 26, 2011, at 4:52 PM, Bryan Schumaker wrote: > nfsiostat was failing to find mounted filesystems on recent kernels due > to changes in the VFS that resulted in a missing "device" tag in the > /proc/self/mountstats file. What was the commit ID that changed this formal kernel API? I'd like to see the justification. > This patch re-adds the "device" tag for NFS > mount data in /proc/self/mountstats. The purpose of mountstats is to be an interface that all file systems can use. If we can't add "device" back to all mounts listed in /proc/self/mountstats, it might be better to adjust nfsiostats to cope. > Signed-off-by: Bryan Schumaker <bjschuma@netapp.com> > --- > fs/nfs/super.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/fs/nfs/super.c b/fs/nfs/super.c > index b961cea..e6a0317 100644 > --- a/fs/nfs/super.c > +++ b/fs/nfs/super.c > @@ -766,8 +766,10 @@ static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt) > devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE); > if (IS_ERR(devname)) > err = PTR_ERR(devname); > - else > + else { > + seq_puts(m, "device "); > seq_escape(m, devname, " \t\n\\"); > + } > free_page((unsigned long)page); > return err; > } > -- > 1.7.6
On 08/27/2011 07:52 PM, Chuck Lever wrote: > > On Aug 26, 2011, at 4:52 PM, Bryan Schumaker wrote: > >> nfsiostat was failing to find mounted filesystems on recent kernels due >> to changes in the VFS that resulted in a missing "device" tag in the >> /proc/self/mountstats file. > > What was the commit ID that changed this formal kernel API? I'd like to see the justification. It was changed by this commit: commit c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9 Author: Al Viro <viro@zeniv.linux.org.uk> Date: Wed Mar 16 06:59:40 2011 -0400 vfs: new superblock methods to override /proc/*/mount{s,info} a) ->show_devname(m, mnt) - what to put into devname columns in mounts, mountinfo and mountstats b) ->show_path(m, mnt) - what to put into relative path column in mountinfo Leaving those NULL gives old behaviour. NFS switched to using those. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> > >> This patch re-adds the "device" tag for NFS >> mount data in /proc/self/mountstats. > > The purpose of mountstats is to be an interface that all file systems can use. If we can't add "device" back to all mounts listed in /proc/self/mountstats, it might be better to adjust nfsiostats to cope. > >> Signed-off-by: Bryan Schumaker <bjschuma@netapp.com> >> --- >> fs/nfs/super.c | 4 +++- >> 1 files changed, 3 insertions(+), 1 deletions(-) >> >> diff --git a/fs/nfs/super.c b/fs/nfs/super.c >> index b961cea..e6a0317 100644 >> --- a/fs/nfs/super.c >> +++ b/fs/nfs/super.c >> @@ -766,8 +766,10 @@ static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt) >> devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE); >> if (IS_ERR(devname)) >> err = PTR_ERR(devname); >> - else >> + else { >> + seq_puts(m, "device "); >> seq_escape(m, devname, " \t\n\\"); >> + } >> free_page((unsigned long)page); >> return err; >> } >> -- >> 1.7.6 > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Aug 29, 2011, at 9:46 AM, Bryan Schumaker wrote: > On 08/27/2011 07:52 PM, Chuck Lever wrote: >> >> On Aug 26, 2011, at 4:52 PM, Bryan Schumaker wrote: >> >>> nfsiostat was failing to find mounted filesystems on recent kernels due >>> to changes in the VFS that resulted in a missing "device" tag in the >>> /proc/self/mountstats file. >> >> What was the commit ID that changed this formal kernel API? I'd like to see the justification. > > It was changed by this commit: > > commit c7f404b40a3665d9f4e9a927cc5c1ee0479ed8f9 > Author: Al Viro <viro@zeniv.linux.org.uk> > Date: Wed Mar 16 06:59:40 2011 -0400 > > vfs: new superblock methods to override /proc/*/mount{s,info} > > a) ->show_devname(m, mnt) - what to put into devname columns in mounts, > mountinfo and mountstats > b) ->show_path(m, mnt) - what to put into relative path column in mountinfo > > Leaving those NULL gives old behaviour. NFS switched to using those. > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> It looks like dropping the "device" tag from /proc/self/mountstats was not intentional, so this is a kernel API regression. At a guess, 2.6.39 probably works right, but 3.0 is broken. Whatever solution we come up with might need to be cc:d to stable@kernel.org. Be sure to verify which released kernels are broken. Does changing nfs_show_devname() to add a "device" tag have any effect on the other two /proc files (mounts and mountinfo)? I suspect you do want to fix show_vfsstat() instead of nfs_show_devname(). This should add "device" only where it is needed, and would work for all file systems. > > >> >>> This patch re-adds the "device" tag for NFS >>> mount data in /proc/self/mountstats. >> >> The purpose of mountstats is to be an interface that all file systems can use. If we can't add "device" back to all mounts listed in /proc/self/mountstats, it might be better to adjust nfsiostats to cope. >> >>> Signed-off-by: Bryan Schumaker <bjschuma@netapp.com> >>> --- >>> fs/nfs/super.c | 4 +++- >>> 1 files changed, 3 insertions(+), 1 deletions(-) >>> >>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c >>> index b961cea..e6a0317 100644 >>> --- a/fs/nfs/super.c >>> +++ b/fs/nfs/super.c >>> @@ -766,8 +766,10 @@ static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt) >>> devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE); >>> if (IS_ERR(devname)) >>> err = PTR_ERR(devname); >>> - else >>> + else { >>> + seq_puts(m, "device "); >>> seq_escape(m, devname, " \t\n\\"); >>> + } >>> free_page((unsigned long)page); >>> return err; >>> } >>> -- >>> 1.7.6 >> >
diff --git a/fs/nfs/super.c b/fs/nfs/super.c index b961cea..e6a0317 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -766,8 +766,10 @@ static int nfs_show_devname(struct seq_file *m, struct vfsmount *mnt) devname = nfs_path(&dummy, mnt->mnt_root, page, PAGE_SIZE); if (IS_ERR(devname)) err = PTR_ERR(devname); - else + else { + seq_puts(m, "device "); seq_escape(m, devname, " \t\n\\"); + } free_page((unsigned long)page); return err; }
nfsiostat was failing to find mounted filesystems on recent kernels due to changes in the VFS that resulted in a missing "device" tag in the /proc/self/mountstats file. This patch re-adds the "device" tag for NFS mount data in /proc/self/mountstats. Signed-off-by: Bryan Schumaker <bjschuma@netapp.com> --- fs/nfs/super.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-)