I'm going to rethink this, as the server may return arbitrarily long bitmaps. I'll probably just always allocate an extra page... -dros > On Nov 15, 2013, at 10:02 AM, "Weston Andros Adamson" <dros@xxxxxxxxxx> wrote: > > Besides storing the ACL buffer, the getacl decoder uses the inline > pages for the attr bitmap and buffer length. __nfs4_get_acl_uncached > must allocate enough page space for all of the data to be decoded. > > This bug results in getxattr() returning ERANGE when the attr buffer > length is close enough to the nearest PAGE_SIZE multiple that adding > the extra bytes leaves too little room for the ACL buffer. > > Signed-off-by: Weston Andros Adamson <dros@xxxxxxxxxx> > --- > fs/nfs/nfs4proc.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index 5ab33c0..006cba1 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -4453,7 +4453,12 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu > .rpc_argp = &args, > .rpc_resp = &res, > }; > - unsigned int npages = DIV_ROUND_UP(buflen, PAGE_SIZE); > + /* > + * extra space needed for attr bitmap and length in getacl decoder. > + * 1 word for bitmap len, 3 words for bitmaps and 1 word for attr len. > + */ > + unsigned int preamble_len = 20; > + unsigned int npages = DIV_ROUND_UP(preamble_len + buflen, PAGE_SIZE); > int ret = -ENOMEM, i; > > /* As long as we're doing a round trip to the server anyway, > -- > 1.8.3.1 (Apple Git-46) > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
