On Fri, Feb 5, 2021 at 8:52 AM Shyam Prasad N <nspmangalore@xxxxxxxxx> wrote:
>
> Looks good to me.
We do need to find out how a single client test could generate ESTALE
though (perhaps we forgot to drop a dentry on delete or rmdir).
The test is doing fsstress, so should be easy enough to shorten it
and repro and find out exactly why the ESTALE is coming.
> Maybe change the FYI in the cifs_dbg line above to VFS?
Probably safer to put a dynamic trace point there in case EACCES or other rc
becomes too common in some scenario.
> On Fri, Feb 5, 2021 at 6:42 AM Aurélien Aptel <aaptel@xxxxxxxx> wrote:
> >
> > From: Aurelien Aptel <aaptel@xxxxxxxx>
> >
> > Assuming
> > - //HOST/a is mounted on /mnt
> > - //HOST/b is mounted on /mnt/b
> >
> > On a slow connection, running 'df' and killing it while it's
> > processing /mnt/b can make cifs_get_inode_info() returns -ERESTARTSYS.
> >
> > This triggers the following chain of events:
> > => the dentry revalidation fail
> > => dentry is put and released
> > => superblock associated with the dentry is put
> > => /mnt/b is unmounted
> >
> > This patch makes cifs_d_revalidate() return the error instead of 0
> > (invalid) when cifs_revalidate_dentry() fails, except for ENOENT (file
> > deleted) and ESTALE (file recreated).
> >
> > Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
> > Suggested-by: Shyam Prasad N <nspmangalore@xxxxxxxxx>
> > CC: stable@xxxxxxxxxxxxxxx
> >
> > ---
> > fs/cifs/dir.c | 22 ++++++++++++++++++++--
> > 1 file changed, 20 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
> > index 68900f1629bff..97ac363b5df16 100644
> > --- a/fs/cifs/dir.c
> > +++ b/fs/cifs/dir.c
> > @@ -737,6 +737,7 @@ static int
> > cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
> > {
> > struct inode *inode;
> > + int rc;
> >
> > if (flags & LOOKUP_RCU)
> > return -ECHILD;
> > @@ -746,8 +747,25 @@ cifs_d_revalidate(struct dentry *direntry, unsigned int flags)
> > if ((flags & LOOKUP_REVAL) && !CIFS_CACHE_READ(CIFS_I(inode)))
> > CIFS_I(inode)->time = 0; /* force reval */
> >
> > - if (cifs_revalidate_dentry(direntry))
> > - return 0;
> > + rc = cifs_revalidate_dentry(direntry);
> > + if (rc) {
> > + cifs_dbg(FYI, "cifs_revalidate_dentry failed with rc=%d", rc);
> > + switch (rc) {
> > + case -ENOENT:
> > + case -ESTALE:
> > + /*
> > + * Those errors mean the dentry is invalid
> > + * (file was deleted or recreated)
> > + */
> > + return 0;
> > + default:
> > + /*
> > + * Otherwise some unexpected error happened
> > + * report it as-is to VFS layer
> > + */
> > + return rc;
> > + }
> > + }
> > else {
> > /*
> > * If the inode wasn't known to be a dfs entry when
> > --
> > 2.29.2
> >
>
>
> --
> Regards,
> Shyam
--
Thanks,
Steve
